Danfoss Hints and tips for the installer Service guide

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MAKING MODERN LIVING POSSIBLE

Fitters Notes

Hints and tips for the installer

REFRIGERATION & AIR CONDITIONING DIVISION

Manual

This Fitters Notes, gives practical hints about Danfoss commercial refrigeration controls (mechanical) and Danfoss compressors.

If you need further information about the Danfoss product range please contact your dealer or local Danfoss agency. You can also ﬁnd some very useful information on our web site:

www.danfoss.com

We hope that this book will help you in your daily work.

Danfoss A/S

Fitters notes

Chapter 1 . . . . . . . . . . . . . . . . . . Thermostatic expansion valves . . . . . . . . . . . . . . . . . . . . . . . . . . .page 3

Chapter 2 . . . . . . . . . . . . . . . . . . Solenoid valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page 13

Chapter 3 . . . . . . . . . . . . . . . . . . Pressure controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page 19

Chapter 4 . . . . . . . . . . . . . . . . . . Thermostats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page 27

expansion valves Solenoid valves Pressure controls Thermostats

Thermostatic

Chapter 5 . . . . . . . . . . . . . . . . . . Pressure regulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page 35

Chapter 6 . . . . . . . . . . . . . . . . . . Water valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page 45

Chapter 7 . . . . . . . . . . . . . . . . . . Filter driers & sight glasses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page 51

Chapter 8 . . . . . . . . . . . . . . . . . . Danfoss compressors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page 61

regulators Water valves

Pressure

Filter driers &

sight glasses

compressors Practical tips Trouble shooting

Danfoss

Chapter 9 . . . . . . . . . . . . . . . . . . Practical tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 125

Chapter 10 . . . . . . . . . . . . . . . . . Trouble shooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 145

Fitters notes Thermostatic expansion valves

Contents Page

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Superheat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Subcooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

External pressure equalization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Charges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Universal charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

MOP charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

MOP ballast charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Thermostatic expansion valve selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Identiﬁcation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Oriﬁce assembly replacement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Danfoss product range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

expansion valves

Thermostatic

Notes

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Fitters notes Thermostatic expansion valves

Thermostatic

expansion valves

A thermostatic expansion valve is built up around a thermostatic element (1) separated from the valve body by a diaphragm.

A capillary tube connects the element to a bulb (2) and a valve body with valve seat (3) and a spring (4).

A thermostatic expansion valve works like this:

The function of a thermostatic expansion valve is determined by three fundamental pressures: P1: Bulb pressure which acts on the upper surface of the diaphragm, in the valve opening direction. P2: Evaporating pressure which acts on the underside of the diaphragm, in the valve closing direction. P3: Spring pressure which also acts on the underside of the diaphragm, in the valve closing direction.

When the expansion valve regulates, balance is created between bulb pressure on one side of the diaphragm and evaporating pressure plus spring force on the other side.

The spring is used to set superheat.

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Introduction

Superheat is measured at the point where the bulb is located on the suction line and is the diﬀ erence between the temperature at the bulb and the evaporating pressure/evaporating temperature at the same point.

Superheat is measured in Kelvin (K) and is used as a signal to regulate liquid injection through the expansion valve.

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Superheat

Subcooling Subcooling is deﬁ ned as the diﬀ erence between

condensing pressure/temperature and liquid temperature at the expansion valve inlet.

Subcooling is measured in Kelvin (K). Subcooling of the refrigerant is necessary to avoid vapour bubbles in the refrigerant ahead of the expansion valve.

Vapour bubbles in the refrigerant reduce capacity in the expansion valve and thereby reduce liquid supply to the evaporator.

Subcooling of 4-5K is adequate in most cases.

Fitters notes Thermostatic expansion valves

External pressure equalization

Expansion valves with external pressure equalization must always be used if liquid distributors are installed.

Typically, the use of distributors gives a pressure drop of 1 bar across distributor and distribution tubes.

Expansion valves with external pressure equalization should always be used in refrigeration systems with heavy evaporators or plate exchangers, where normally the pressure drop will be greater than pressure corresponding to 2K.

Charges Thermostatic expansion valves can contain one

of three diﬀerent types of charge:

1. Universal charge

2. MOP charge

3. MOP charge with ballast, standard for Danfoss expansion valves with MOP.

Universal charge

Expansion valves with Universal charge are used in most refrigeration systems where there is no pressure limitation requirement and where the bulb can be located warmer than the element or at high evaporating temperature/evaporating pressure.

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MOP charge

Universal charge means that there is liquid charge in the bulb. The amount of charge is so large that charge remains in the bulb irrespective of whether the element is colder or warmer than the bulb.

Expansion valves with MOP charge are typically used on factory-made units where suction pressure limitation on starting is required, e.g. in the transport sector and in air conditioning systems.

All expansion valves with MOP have a very small charge in the bulb.

This means that the valve or the element must be located warmer than the bulb. If it is not, charge can migrate from the bulb to the element and prevent the expansion valve from functioning.

MOP charge means limited liquid charge in the bulb.

“MOP” stands for Maximum Operating Pressure and is the highest suction pressure/ evaporating pressure permissible in the evaporator/suction line.

The charge will have evaporated when the temperature reaches the MOP point. Gradually, as the suction pressure rises, the expansion valve begins to close at approx. 0.3/0.4 bar below the MOP point. It becomes completely closed when the suction pressure is the same as the MOP point.

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MOP is often called “Motor Overload Protection”.

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Fitters notes Thermostatic expansion valves

MOP ballast charge

Thermostatic expansion valve selection

Expansion valves with MOP ballast charges are used mainly in refrigeration systems with “highdynamic” evaporators, e.g. in air conditioning systems and plate heat exchangers with high heat transfer.

With MOP ballast charge, up to 2 - 4 K less superheat can be obtained than with other types of charge.

The bulb in a thermostatic expansion valve contains a material of high porosity and large surface area in relation to weight.

MOP charge with ballast has a damping eﬀect on expansion valve regulation.

The valve opens slowly as bulb temperature rises and closes quickly as bulb temperature fails.

The thermostatic expansion valve can be selected when the following are known:

Refrigerant Evaporator capacity Evaporating pressure Condensing pressure

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Subcooling Pressure drop across valve Internal or external pressure equalization

expansion valves

Thermostatic

Identiﬁcation The thermostatic element is ﬁtted with a laser

engraving on top of the diaphragm. The code refers to the refrigerant for which the

valve is designed: L = R410A N = R134a S = R404A/ R507 X = R22 Z = R407C

This engraving gives valve type (with code number), evaporating temperature range, MOP point, refrigerant, and max. working pressure, PS/MWP.

With TE 20 and TE 55 the rated capacity is stamped on a band label fastened to the valve.

The oriﬁce assembly for T2 and TE2 is marked with the oriﬁce size (e.g. 06) and week stamp + last number in the year (e.g. 279). The oriﬁce assembly number is also given on the lid of its plastic container.

On TE 5 and TE 12 the upper stamp (TE 12) indicates for which valve type the oriﬁce can be used. The lower stamp (01) is the oriﬁce size.

On TE 20 and TE 55 the lower stamp (50/35 TR N/B) indicates the rated capacity in the two evaporating temperature ranges N and B, and the refrigerant. (50/35 TR = 175 kW in range N and 123 kW in range B).

The upper stamp (TEX 55) refers to the valve type for which the assembly can be used.

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Fitters notes Thermostatic expansion valves

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The bulb is best mounted on a horizontal suction line tube and in a position corresponding to between 1 o’clock and 4 o’clock.

Location depends on the outside diameter of the tube.

Note: The bulb must never be located at the bottom of the suction line due to the possibility of oil laying in the bottom of the pipe causing false signals.

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Installation The expansion valve must be installed in the

liquid line, ahead of the evaporator, with its bulb fastened to the suction line as close to the evaporator as possible.

If there is external pressure equalization, the equalizing line must be connected to the suction line immediately after the bulb.

The bulb must not be installed after a heat exchanger because in this position it will give false signals to the expansion valve.

The bulb must not be installed close to components of large mass as this also will give rise to false signals to the expansion valve

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The bulb must be able to sense the tem pe ra tu re of the superheated suction vapour and must therefore not be located in a position that will expose it to extraneous heat/cold.

If the bulb is exposed to a warm air current, insulation of the bulb is recommended.

The Danfoss bulb strap allows a tight and secure ﬁ tting of the bulb to the tube, thereby securing that the bulb has ultimate thermal contact to the suction tube. The TORX design of the screw makes it easy for the ﬁ tter to transfer the torque from the tool to the screw without having to press the tool into the screw slot. Furthermore, with the TORX slot design, there is no risk of damaging the screw slot.

Fitters notes Thermostatic expansion valves

Installation (cont.)

As previously mentioned, the bulb must be installed to the horizontal part of the suction line immediately after the evaporator. It must not be installed to a collection tube or a riser after an oil pocket.

The expansion valve bulb must always be installed ahead of any liquid lock.

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expansion valves

Thermostatic

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Setting The expansion valve is supplied with a factory

setting suitable for most applications. If necessary, readjustment can be made using the

setting spindle on the valve. Turning the spindle clockwise increases the

expansion valve superheat and turning it counterclock-wise reduces it.

For T /TE 2, one turn of the spindle produces a change of approx. 4K in the superheat at 0°C evaporating temperature.

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Fitters notes Thermostatic expansion valves

Setting (cont.)

For TE 5 and following sizes, one turn of the spindle produces a change of approx. 0.5K in the superheat at 0°C evaporating temperature.

For TUA and TUB, one turn of the spindle produces a change of approx. 3K in the superheat at 0°C evaporating temperature.

Hunting in the evaporator can be eliminated by the following procedure: Increase the superheat by turning the expansion valve setting spindle well to the right (clockwise) so that hunting stops. Then turn the setting spindle in counter-clockwise steps so that hunting again occurs.

From this position, turn the spindle about once clockwise (but only 1/4 turn for T /TE 2 valves).

On this setting the refrigeration system will not hunt and the evaporator is fully utilized. A variation of 1 K in superheat is not regarded as hunting.

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Oriﬁce assembly replacement

If the superheat in the evaporator is too high, the reason might be an inadequate supply of liquid refrigerant.

The superheat can be reduced by turning the expansion valve setting spindle counterclockwise in steps until hunting is observed.

From this setting, the spindle must be turned about once clockwise (but only 1/4 turn for T/TE

2). This setting fully utilizes the evaporator. A variation of 1 K in superheat is not regarded as hunting.

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If the evaporator continues to hunt, regardless of the superheat setting, the valve capacity might be too high and the oriﬁce assembly, or the valve, needs replacing with a smaller one.

If the evaporator superheat is too high the valve capacity is too low and the oriﬁce assembly must be replaced with a larger one.

TE, T2, TUA, TCAE valves are supplied with an interchangeable oriﬁce.

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Fitters notes Thermostatic expansion valves

Danfoss product range Thermostatic expansion valves

Danfoss oﬀers a comprehensive range of thermostatic expansion valves with capacities from 0.4 to 1083 kW (R134a).

T/TE 2 valves have a brass housing and ﬂare/ ﬂare or solder/ﬂare connections.

Rated capacity: 0.4 - 10.5 kW (R134a).

TUA, TUB, TUC valves have a stainless steel housing and stainless steel/copper bimetal solder connections.

Rated capacity: 0.5 - 12 kW (R134a).

The valves can be supplied with or without external pressure equalization.

TUA has an interchangeable oriﬁce assembly and adjustable superheat.

TUB has a ﬁxed oriﬁce and adjustable superheat.

TUC has a ﬁxed oriﬁce and factory set superheat.

TUB and TUC are primarily for OEM customers. All TUB and TUC valves can be replaced by TUA valves.

TCAE, TCBE, TCCE valves have a stainless steel housing and stainless steel/copper bimetal solder connections.

Rated capacity: 12 - 18 kW (R134a).

The valves are designed as the TU valves but with a higher capacity.

TDE valves have a brass housing and copper solder connections.

Rated capacity: 10.5 - 140 kW (R407C)

The valves are supplied with a ﬁxed oriﬁce and adjustable superheat.

TE 5 - TE 55 valves have a brass housing. The valves are supplied as a part programme consisting of valve housing, oriﬁce and thermostatic element.

The valve housing is available in a straightway or angleway version with solder, ﬂare and ﬂange connections.

Rated capacity: 12.9 - 220 kW (R134a).

The valves are supplied with external pressure equalization.

PHT 85 - 300 valves are supplied as a part programme consisting of valve housing, ﬂanges, oriﬁce and thermostatic element.

Rated capacity: 55 - 1083 kW (R134a).

For further information consult the internet or the catalogue material.

expansion valves

Thermostatic

The valves are supplied with external pressure equalization.

TRE valves have a brass housing and stainless steel/copper bimetal connections.

Rated capacity: 18 - 196 kW (R134a).

The valves are supplied with a ﬁxed oriﬁce and adjustable superheat.

Fitters notes Solenoid valves

Contents Page

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

EVRA 32 & 40 precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

When pressure testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

The coil. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

The correct product. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Solenoid valves

Notes

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Fitters notes Solenoid valves

Installation

All EVR/EVRA, and EVH types solenoid valves operate only when installed correctly in the direction of ﬂow, i.e. in the direction indicated by the arrow.

Normally, solenoid valves installed ahead of a thermostatic expansion valve must be close to that valve.

This avoids liquid hammer when the solenoid valve opens.

Ensure that pipes around the valve are properly installed so that no fracture can occur.

Solenoid valves

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EVRA 32 & 40 precautions

Brazing/welding EVR/EVRA and EVH solenoid valves does not normally necessitate dismantling, provided steps are taken to avoid heating the valve.

Note! Always protect the armature tube against weld spatter.

After tacking the valve to the pipe, remove the valve body to protect O-rings and gaskets against heat. In installations with welded steel pipe, a FA type strainer or similar mounted ahead of the solenoid valve is recommended. (On new plant, ﬂushing out before starting up is recommended).

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Fitters notes Solenoid valves

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All solenoid valves in the system must be open, either by applying voltage to the coils or by opening the valves manually (provided a manual operation spindle is ﬁ tted).

Remember to screw the spindle back before starting up, otherwise the valve will be unable to close.

When pressure testing

Always use counter force when ﬁ nally tightening the solenoid valve on pipes, i.e. two spanners on the same side of the valve.

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Fitters notes Solenoid valves

The coil

When ﬁtting the coil, it has merely to be pressed down over the armature tube until a click is heard. This means that the coil has been correctly ﬁtted.

Note: Remember to ﬁt an O-ring between valve body and coil.

Be sure that the O-ring is smooth, not damaged and that the surface is free from paint or any other material.

Note: The O-ring must be changed at service.

The coil can be removed by inserting a screwdriver between valve body and coil. The screwdriver can then be used as a lever to loosen the coil.

Solenoid valves

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Be careful with cable entries. It must not be possible for water to enter the terminal box. The cable must be led out via a drip loop.

The entire cable circumference must be retained by the cable entry.

Therefore, always use round cable (which is the only type of cable that can be sealed eﬀectively).

Be aware of the colour of leads in the cable. Yellow/green is always earth. Leads of one colour are either phase or neutral.

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Fitters notes Solenoid valves

The coil (cont.)

The correct product

(The “old” coil type)

When removing a coil it might be necessary to use hand tools, e.g. two screwdrivers.

Make sure that coil data (voltage and frequency) and supply voltage correspond. If they do not, the coil might burn out. Always ensure that valve and coil match each other.

When replacing a coil in an EVR 20 NC (NC = normally closed) note:

- A valve body using an a.c. coil has a square armature.

- A valve body using a d.c. coil has a round armature.

Fitting the wrong coil results in a lower MOPD. See data on the top nut. As far as possible, always choose single-frequency coils. These give oﬀ less heat than double-frequency coils. Use NC (normally closed) solenoid valves for systems in which the valve must remain closed (de-energised) for most of the operating time. Use NO (normally open) solenoid valves for systems in which the valve must remain open (de-energised) for most of the operating time. Never replace an NO (normally open) solenoid valve with an NC (normally closed) valve - or vice versa.

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(The new “clip-on” coil type)

Two labels are supplied with each clip-on coil (see illustration).

The adhesive label is for attaching to the side of the coil, while the other, perforated label should be placed over the armature tube before the coil is clicked into position.

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Fitter notes Pressure controls

Contents Page

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Placing of surplus capillary tube. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Low-pressure control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

High-pressure control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Example with four compressors in parallel (R404A). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Setting LP for outdoor location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Indicative evaporating pressures (pe) for diﬀerent types of systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Test of contact function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

The correct pressure control for your system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Pressure controls

Notes

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Fitter notes Pressure controls

Installation

Mount the KP pressure control on a bracket or on a completely ﬂat surface.

The pressure control can also be mounted on the compressor itself.

In unfavourable conditions, an angle bracket could amplify vibration in the mounting plane. Therefore, always use a wall bracket where strong vibration occurs.

If the risk of water droplets or water spray is present, the accompanying top plate should be used. The plate increases the grade of enclosure to IP 44 and is suitable for all KP pressure controls. To obtain IP 44, the holes in the backplate of the control must be covered by mounting on either an angle bracket (060-105666) or a wall plate (060-105566).

The top plate is supplied with all units incorporating automatic reset. It can also be used on units with manual reset, but in that case must be purchased separately (code no.: for single unit, 060-109766; for dual unit, 060-109866).

If the unit is to be used in dirty conditions or where it might be exposed to heavy spray - from above or from the side - it should be ﬁtted with a protective cap. The cap can be used together with either an angle bracket or a wall bracket.

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Pressure controls

Al0_0008

If the unit risk being exposed to heavy water inﬂuence a better grade of enclosure can be achieved when mounting the product in a special IP 55 enclosure.

The IP 55 enclosure is available for both single unit (060-033066) and dual unit (060-035066).

Ak0_0020

Fitter notes Pressure controls

Installation (cont.)

Placing of surplus capillary tube

The pressure connection of the control must always be ﬁtted to the pipe in such a way that liquid cannot collect in the bellows. This risk is present especially when:

the unit is located in a low ambient condition, e.g. in an air current,

the connection is made on the underside of the pipe.

Such liquid could damage the high-pressure control.

Consequently, compressor pulsation would not be damped and might give rise to contact chatter.

Surplus capillary tube can fracture if vibration occurs and might lead to complete loss of system charge. It is therefore very important that the following rules are observed:

When mounting direct on compressor: Secure the capillary tube so that the compressor/control installation vibrates as a whole. Surplus capillary tube must be coiled and bound.

Note:

According to EN rules it is not allowed to use capillary tube for connecting safety pressure controles. In such case a 1/4 inch tube is prescribed.

Al0_0009

Al0_0010

Setting

Low-pressure control

High-pressure control

Other types of mounting: Coil surplus capillary tube into a loose loop. Secure the length of capillary tube between compressor and loop to the compressor.

Secure the length of capillary tube between loop and pressure control to the base on which the pressure control is mounted.

In case of very strong vibrations, Danfoss steel capillary tubes with ﬂare connection are recommended: Code no. 0.5 m = 060-016666 Code no. 1.0 m = 060-016766 Code no. 1.5 m = 060-016866

KP pressure controls can be preset using a compressed air cylinder. Ensure that the change-over contacts are correctly connected for the required function.

Set the start pressure (CUT IN) on the range scale (A). Then set the diﬀerential on the diﬀerential scale (B). Stop pressure = CUT IN minus DIFF.

Set the stop pressure (CUTOUT) on the range scale (A). The set the diﬀerential on the diﬀerential scale (B). Start pressure = CUT OUT minus DIFF.

Remember: The scales are indicative only.

Al0_0011

Al0_0012

22 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitter notes Pressure controls

Example with four compressors in parallel (R404A)

Setting LP for outdoor location

Indicative evaporating pressures (pe) for diﬀerent types of systems

Medium: ice cream at –25°C, t0 ≈ –37°C,

Compressor CUT OUT CUT IN

p0 ≈ –0.5 bar, ∆p suction line corresponding to 0.1 bar.

Each pressure control (e.g. KP 2) must be set individually in accordance with the following table.

The pressure control must be mounted in such a way that liquid cannot collect in the bellows.

If the compressor, condenser and receiver are situated outdoors, KP low pressure must be set to a “CUT IN” setting lower than the lowest occurring pressure (temperature around compressor) during winter operation. In this case, after longer standstill periods the pressure in the receiver determines the suction pressure.

Example:

Lowest occurring temperature around the compressor –20°C means, for R404A, a pressure of 1 bar. CUT IN must be set at –24°C (corresponding to 1.6 bar).

Al0_0013

Room temp. (tr) System type Diﬀerence

+0.5°/+2°C Fan-cooled

meat cold room

+0.5°/+2°C Meat cold room with

natural air circulation

–1°/0°C Refrigeration meat

counter (open)

+2°/+6°C Milk cold room 14K 1.0 bar

0°/+2°C Fruit cold room

Vegetable chiller

–24°C Freezer 10K 1.6 bar

–30°C Ventilated deep

freeze room

–26°C Ice cream freezer 10K 1.4 bar

between te and t

media

10K 1.0 - 1.1 bar

12K 0.8 - 0.9 bar

14K 0.6 bar

6K 1.3 - 1.5 bar

10K 1 bar

Evaporating pressure (pe)

(air)

(R134a)

(R404A)

1 –0.05 bar 0.35 bar 2 0.1 bar 0.5 bar 3 0.2 bar 0.6 bar 4 0.35 bar 0.75 bar

Setting of KP2/KP1

[%]

(cut in - cut out) D = Operating press. cont. S = Safety press. cont.

85 0.9 - 2.1 bar (D)

85 0.7 - 2.1 bar (D)

85 0.5 - 1.8 bar (D)

85 0.7 - 2.1 bar (D)

90 1.2 - 2.1 bar (D)

90 0.7 - 2.2 bar (S)

90 0.3 - 2.7 bar (S)

90 0.5 - 2.0 bar (S)

Pressure controls

Al0_0015

Fitter notes Pressure controls

Test of contact function

When the electrical leads are connected and the system is under normal operating pressure, the contact function can be tested manually.

Depending on the bellows pressure and setting, the test device must be pressed up or down.

Any reset mechanism becomes inoperative during the test.

On single units:

Use the test device at top left.

On dual units:

Use the test device on the left for low-pressure testing and the one at bottom right for highpressure testing.

Al0_0018

Warning! The contact function on a KP Pressure Control must never be tested by activating the device at top right. If this warning is ignored, the control may go out of adjustment. In the worst case function can be impaired.

Al0_0019

On the KP 15 dual pressure control with optional automatic or manual reset on low-pressure and high-pressure side, automatic reset must be set when servicing is being carried out. The pressure control can then automatically restart. Remember, the original reset function must be set after servicing.

The pressure control can be protected against being set on automatic reset: Simply remove the washer controlling the reset function! If the unit is to be protected against tampering, the washer can be sealed with red lacquer.

Al0_0020

Low pressure Manual reset *) Automatic reset Automatic reset Manual reset

High pressure Manual reset *) Manual reset Automatic reset Automatic reset

*) Factory setting

Al0_0021

24 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitter notes Pressure controls

The correct pressure control for your system

KP with solder connections can be used instead of ﬂare connections on hermetic systems.

In ammonia plant where KP pressure controls are used, they must be type KP-A. A connector with M10 × 0.75 – 1/ no. 060- 014166).

- 18 NPT (code

Al0_0006

Pressure controls

For refrigerating systems containing a large quantity of charge medium and where extra safety is desired/demanded (Fail-safe): Use KP 7/17 with double bellows. The system will stop if one of the bellows ruptures - without loss of charge.

For systems operating with low pressure on the evaporator side, and where the pressure control must regulate (not just monitor): Use KP 2 with a small diﬀerential. An example where pressure control and thermostat are in series:

KP 61 regulates the temperature via compressor stop/start. KP 2 stops the compressor when suction pressure becomes too low.

KP 61: CUT IN = 5°C (2.6 bar) CUT OUT = 1°C (2.2 bar)

KP 2 low pressure: CUT IN = 2.3 bar CUT OUT = 1.8 bar

Al0_0002

Al0_0003

Al0_0004

Fitter notes Pressure controls

The correct pressure control for your system (cont.)

For systems where KP is activated occasionally (alarm) and for systems where KP is the signal source for PLC, etc.: Use KP with gold contacts; these give good contact at low voltages.

Al0_0005

26 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Thermostats

Contents Page

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

KP thermostat with air sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Thermostats with automatic reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Thermostats with maximum reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Thermostats with minimum reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Setting example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Test of contact function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

KP 98 dual thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

The correct thermostat for your refrigeration system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Vapour charge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Absorption charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Low voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Placing of surplus capillary tube. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Thermostats with vapour charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Thermostats

Notes

28 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Thermostats

Installation

If the risk of water droplets or water spray is present, ﬁt a top plate. The plate increases the grade of enclosure to IP 44 and is suitable for all KP thermostats. The top plate must be purchased separately (Code no.: for single unit, 060-109766; for dual unit, 060-109866).

To obtain IP 44, cover all holes in the backplate of the thermostat.

If the unit is to be used in dirty conditions or where it might be exposed to heavy spray it should be ﬁtted with a protective cap. The cap can be used together with either an angle bracket (060-105666) or a wall bracket (060-

105566).

Aj0_0001

Thermostats

KP thermostat with air sensor

Aj0_0002

If the unit risk being exposed to heavy water inﬂuence a better grade of enclosure can be achieved when mounting the product in a special IP 55 enclosure The IP 55 enclosure is available for both single unit (060-033066) and dual unit (060-035066).

Ak0_0020

Remember that the diﬀerential is aﬀected by air circulation around the sensor. Insuﬃcient air circulation can increase the diﬀerential by 2-3°C.

Place the room thermostat so that air is able to ﬂow freely around the sensor. At the same time, ensure that the sensor is not exposed to draughts from doors or radiation from the evaporator surface.

Never place the thermostat directly on a cold wall; this increases the diﬀerential. Instead, mount the unit on an insulating plate.

Aj0_0003

Fitters notes Thermostats

KP thermostat with air sensor (cont.)

Setting

Thermostats with automatic reset

When placing the sensor: Remember that air must be able to circulate freely around the sensor. With control from, for example, return air temperature, the sensor must not touch the evaporator.

KP thermostat with cylindrical sensor

There are three ways of securing the sensor:

1) The pipe.

2) Between evaporator ﬁns.

3) In a pocket.

Always set the highest temperature on the range scale. Then set the diﬀerential on the DIFF scale.

The temperature setting on the range scale then corresponds to the temperature at which a refrigeration compressor will be started on rising temperature. The compressor will stop when the temperature corresponds to the value set on the DIFF scale.

For pre-setting of vapour charged thermostats, the graph curves stated in the customer instruction sheet should be used. If the compressor will not stop when it is set for low stop temperatures: Check to see whether the diﬀerential has been set at too high a value.

Ah0_0006

When using a pocket: Always use heat-conductive compound (code no. 041E0110) to ensure good contact between sensor and medium.

Aj0_0004

Aj0_0005

Thermostats with maximum reset

Set the highest temperature = stop temperature on range scale.

The diﬀerential setting is ﬁxed. When the temperature on the thermostat sensor corresponds to the diﬀerential setting, the system can be restarted by pressing the "Reset" button.

Thermostats with minimum reset

Set the lowest temperature = stop temperature on range scale. The diﬀerential setting is ﬁxed. When the temperature around the thermostat sensor has risen to the diﬀerential setting, the compressor can be restarted by pressing the “Reset” button.

Aj0_0006

30 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Thermostats

Setting example

Test of contact function

The temperature in a deep freeze room is to be controlled by a thermostat that closes a solenoid valve. The system is of the pump-down type and is stopped via a low-pressure control. Here, the pressure control must not be set to cut out at a pressure lower than necessary. At the same time, it must cut in at a pressure corresponding to the cut-in temperature of the thermostat.

Example:

Deep freeze room with R404A Room temperature: –20°C Thermostat cut out temperature: –20°C Thermostat cut in temperature: –18°C Pressure control cut out pressure: 0.9 bar (–32°C) Pressure control cut in pressure: 2.2 bar (–18°C)

Thermostats

Aj0_0007

When the electrical leads are connected, the contact function can be tested manually. Depending on the sensor temperature and the thermostat setting, the test device must be pressed up or down. Any reset mechanism becomes inoperative during the test.

Use the test device at top left.

KP 98 dual thermostat

Aj0_0009

Warning! The contact function on a KP single thermostat must never be tested by activating the device on the righthand side. If this warning is ignored, the thermostat might go out of adjustment. In the worst case, function can be impaired.

Use the test device on the lefthand side to test function on rising oil temperature and the test device at bottom right to test function on rising pressure gas temperature.

Aj0_0010

Fitters notes Thermostats

The correct thermostat for your refrigeration system

Vapour charge

Absorption charge

A thermostat must contain the correct charge, as described below.

Low temperatures, coldest bellows, not enclosure-sensitive. Thermostat with air coil: On gradual temperature rise and fall (less than 0.2K/min), e.g. in large, sluggish cold rooms containing many items, KP 62 with vapour charge is recommended.

High temperatures, enclosure-sensitive. Bellows colder or warmer. Thermostat with air coil: On fast changes in temperature (more than 0.2K/ min), e.g. in smaller cold rooms where the produce turnover rate is high, KP 62 with absorption charge is recommended.

Straight capillary tube

60I8012

Remote air coil

60I8032

Vapour charge

Air coil (integral with thermostat)

60I8013

Double contact remote bulb

60I8017

Cylindric remote bulb

60I8008

Low voltage

For systems where KP is activated occasionally (alarm) and for systems where KP is the signal source for PLC, etc. (low voltage): Use KP with gold contacts; these give good contact at low voltages.

Absorption charge

Aj0_0012

Air coil (integral with thermostat)

60I8013

Remote air coil (for duct mounting)

60I8018

32 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Thermostats

Placing of surplus capillary tube

Thermostats with vapour charge

Dual thermostat KP 98:

Surplus capillary tube can fracture if vibration occurs and might lead to loss of thermostat charge. It is therefore very important that the following rules be observed:

When mounting direct on compressor: Secure the capillary tube so that the compressor/thermostat installation vibrates as a whole. Surplus capillary tube must be coiled and bound.

Other types of mounting: Coil surplus capillary tube into a loose loop. Secure the length of capillary tube between compressor and loop to the compressor. Secure the length of capillary tube between loop and thermostat to the base on which the thermostat is mounted.

Never locate a KP thermostat with vapour charge in a room where the temperature is or can be lower than that in the cold room.

Aj0_0017

Thermostats

Never allow the capillary tube from a KP thermostat to run alongside of a suction line in a wall entry.

Aj0_0014

Aj0_0015

Fitters notes Pressure regulators

Contents Page

Application. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

KVP evaporating pressure regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

KVR condensing pressure regulator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

KVL crankcase pressure regulator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

KVC capacity regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

KVD receiver pressure regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Identiﬁcation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Soldering/brazing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Pressure testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Evacuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

KVP evaporating pressure regulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

KVL crankcase pressure regulators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

KVR + NRD condensing pressure regulators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

KVR + KVD condensing pressure regulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Danfoss pressure regulators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

regulators

Pressure

Notes

36 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Pressure regulators

Application

KVP evaporating pressure regulator

Type KV pressure regulators will control the low and high pressure sides of the system under varying load conditions:

KVP is used as an evaporating pressure regulator. KVR is used as a condensing pressure regulator. KVL is used as a crankcase pressure regulator. KVC is used as a capacity regulator. NRD is used as a diﬀerential pressure regulator and as a receiver pressure regulator. KVD is used as a receiver pressure regulator. CPCE is used as a capacity regulator.

The evaporating pressure regulator is installed in the suction line after the evaporator to regulate the evaporating pressure in refrigeration systems with one or more evaporators and one compressor.

In such refrigeration systems (operating on diﬀerent evaporating pressures) KVP is installed after the evaporator with the highest evaporating pressure.

Each evaporator is activated by a solenoid valve in the liquid line. The compressor is contolled by a pressure switch in a pump down function. The maximum pressure on the suction side corresponds to the lowest room temperature.

Ak0_0031

Ak0_0025

regulators

Pressure

In refrigeration systems with parallel coupled evaporators and common compressors, and where the same evaporating pressure is required, KVP must be installed in the common suction line.

The KVP evaporating pressure regulator has a pressure gauge connection for use when setting the evaporating pressure. KVP maintains constant pressure in the evaporator.

KVP opens on rising inlet pressure (evaporating pressure).

Ak0_0019

Ak0_0023

Fitters notes Pressure regulators

KVR condensing pressure regulator

KVR is normally installed between the air-cooled condenser and the receiver. KVR maintains constant pressure in air-cooled condensers. It opens on rising inlet pressure (condensing pressure).

KVR together with a KVD or an NRD ensures a suﬃciently high liquid pressure in the receiver during varying operating conditions. The KVR condensing pressure regulator has a pressure gauge connection for use when setting the condensing pressure.

Ak0_0026

In situations where both the air-cooled condenser and the receiver are located outdoors in very cold surroundings it can be diﬃcult to start the refrigeration system after a long standstill period.

In such conditions, KVR is installed ahead of the air-cooled condenser, with an NRD in a bypass line around the condenser.

NRV prevent back ﬂow during start up process.

Ak0_0027

KVR is also used in heat recovery. In this application, KVR is installed between the heat recovery vessel and condenser.

It is necessary to install an NRV between condenser and receiver in order to prevent backcondensation of the liquid in the condenser.

Ak0_0028

KVR can be used as a relief valve in refrigeration systems with automatic defrosting. Here, KVR is installed between the outlet tube from evaporator and receiver.

Note!

KVR must never be used as a safety valve.

Ak0_0029

KVL crankcase pressure regulator

KVL crankcase pressure regulator limits compressor operation and start-up if the suction pressure becomes too high.

It is installed in the refrigeration system suction line immediately ahead of the compressor.

KVL is often used in refrigeration systems with hermetic or semihermetic compressors designed for low-temperature ranges.

KVL opens on falling outlet pressure (suction pressure).

Ak0_0024

38 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Pressure regulators

KVC capacity regulator

KVC is used for capacity regulation in refrigeration systems where low-load situations occur and where it is necessary to avoid low suction pressure and “compressor cycling”. Too low a suction pressure will also cause vacuum in the refrigeration system and thus create the risk of moisture ingress in refrigeration systems with open compressor. KVC is normally installed in a bypass line between compressor discharge tube and suction tube. KVC opens on falling outlet pressure (suction pressure).

Ak0_0030

A CPCE capacity regulator can be used as an alternative to KVC if the requirement is greater accuracy in the regulation, low suction pressure or if higher pressure drop is given between CPCE outlet and the suction pressure.

KVD receiver pressure regulator

KVC can also be installed in a bypass line from the compressor discharge pipe, with valve outlet led to a point between expansion valve and evaporator.

This arrangement can be used on a liquid cooler with several parallelcoupled compressors and where no liquid distributor is used.

KVD is used to maintain suﬃciently high receiver pressure in refrigeration systems with or without heat recovery.

KVD is used together with a KVR condensing pressure regulator.

The KVD receiver pressure regulator has a pressure gauge connection for use when setting receiver pressure.

KVD opens on falling outlet pressure (receiver pressure).

Ak0_0002

Ak0_0003

regulators

Pressure

Ak0_0004

Fitters notes Pressure regulators

Identiﬁcation

All KV pressure regulators carry a label giving the valve function and type, e.g. CRANKCASE PRESS. REGULATOR type KVL.

The label also gives the operating range of the valve and its max. permissible working pressure (PS/MWP).

A double-ended arrow (“+” and “-“) is printed on the bottom of the label. Direction “+” (plus) means higher pressure and “–“ (minus) means lower pressure.

KV pressure regulators can be used with all existing refrigerants except ammonia (NH3), provided valve pressure ranges are respected.

The valve body is stamped with the valve size, e.g. KVP 15, with an arrow to indicate valve ﬂow direction.

Ak0_0032

Ak0_0005

Installation

Soldering/brazing

Ensure that piping around KV valves is clean and well-secured. This will protect valves against vibration.

All KV pressure regulators must always be installed so that ﬂow is in the direction of the arrow.

KV pressure regulators can otherwise be installed in any position, but they must never be able to create an oil or liquid lock.

Ak0_0006

During soldering, it is important to wrap a wet cloth around the valve.

Always point the gas ﬂame away from the valve so that the valve is never subjected to direct heat. When soldering, be careful not to leave soldering material in the valve as this can impair function.

Before soldering a KV valve, be sure that any pressure gauge insert has been removed. Always use inert gas when soldering KV valves.

Ak0_0007

Warning! Alloys in soldering materials and ﬂux give oﬀ smoke which can be hazardous to health. Please read

gases. It is a good idea to use safety goggles. Soldering while refrigerant is present in the

system is not recommended. suppliers’ instructions and follow their safety precautions. Keep the head away from the smoke during soldering. Use good ventilation and/or an extract at the ﬂame and do not inhale smoke and

Aggressive gases might be created which can, for

example, break down the bellows in KV valves or

other parts in the refrigeration system.

40 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Pressure regulators

Pressure testing

Evacuation

KV pressure regulators can be pressure-tested after they have been installed, provided the test pressure does not exceed the maximum permissible pressure on the valves.

The maximum test pressure for KV valves is shown in the table.

During evacuation of the refrigeration system, all KV valves must be open.

Factory-set KV valves will have the following positions when supplied: KVP, closed KVR, closed KVL, open KVC, open KVD, open

It is therefore necessary to screw the setting spindle of KVP and KVR right back counterclockwise during system evacuation.

In individual cases it can be necessary to evacuate from both discharge side and lowpressure side in the refrigeration system.

Evacuation through the pressure gauge connections of KVP, KVR and KVD is not advisable because the oriﬁce in these ports are very small.

Type Test pressure, bar

KVP 12 - 15 - 22 28 KVP 28 - 35 25 KVL 12 - 15 - 22 28 KVL 28 - 35 25 KVR 12 - 15 - 22 31 KVR 28 - 35 31 KVD 12 - 15 31 KVC 12 - 15 - 22 31

regulators

Pressure

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Fitters notes Pressure regulators

Setting

KVP evaporating pressure regulators

When setting KV pressure regulators in refrigeration systems it can be a good idea to use the factory setting as the starting-out point.

The factory setting for individual pressure regulators can be found again by measuring from the top of the valve to the top of the setting screw.

The table shows the factory setting, the distance “x” and the pressure change per revolution of the setting screw for all KV types.

KVP evaporating pressure regulators are always supplied with a factory setting of 2 bar. Turning clockwise gives higher pressure and turning counterclockwise gives lower pressure.

After the system has been in normal operation for a time, ﬁne adjustment is necessary. Always use a pressure gauge when making ﬁne adjustments.

If KVP is used for frost protection, ﬁne adjustment must be made when the system is operating under minimum load.

Remember to always replace the protective cap on the setting screw after ﬁnal setting.

Type

KVP 12 - 15 - 22 2 bar 13 0.45 KVP 28 - 35 2 bar 19 0.30 KVL 12 - 15 - 22 2 bar 22 0.45 KVL 28 - 35 2 bar 32 0.30 KVR 12 - 15 -22 10 bar 13 2.5 KVR 28 - 35 10 bar 15 1.5 KVD 12 - 15 10 bar 21 2.5 KVC 12 - 15 - 22 2 bar 13 0.45

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Factory

setting

X mm bar/rev.

KVL crankcase pressure regulators

KVR + NRD condensing pressure regulators

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KVL crankcase pressure regulators are always supplied with a factory setting of 2 bar.

Turning clockwise gives higher pressure and turning counterclockwise gives lower pressure.

The factory setting is the point at which KVL begins to open or where it just closes. Since the compressor must be protected, the KVL setting is the max. permissible suction pressure of the compressor.

The setting must be made using the compressor suction pressure gauge.

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In refrigeration systems with KVR + NRD, the setting of KVR must give a suitable receiver pressure.

Pressure in the condenser of between 1.4 and 3.0 bar (pressure drop across NRD) higher than the pressure in the receiver should be acceptable. If it cannot be accepted, an arrangement with KVR + KVD must be used.

This setting is best made during operating in a winter period.

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42 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Pressure regulators

KVR + KVD condensing pressure regulators

In refrigeration systems with KVR + KVD, the condensing pressure must ﬁrst be set with KVR while KVD is closed (setting screw turned back fully counterclockwise).

Then, KVD must be set to a receiver pressure, e.g. about 1 bar lower than condensing pressure. A pressure gauge must be used for this setting which is best made during operation in a winter period.

If the condensing pressure is set during summer operation, one of two procedures can be used:

1) In a newly-installed refrigeration system with a KVR/KVD setting of 10 bar as the starting out point, the system can be set by counting the number of turns on the setting screw.

2) In an existing refrigeration system, where the KVR/KVD setting is not known, the

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starting-out point must ﬁrst be established. The number of turns on the setting screw can then be counted.

Danfoss pressure regulators

Product Used as Opens Pressure range

KVP Evaporating pressure regulator on a rise in pressure on the inlet side 0 - 5.5 bar

KVR Condensing pressure regulator on a rise in pressure on the inlet side 5 - 17.5 bar

regulators

Pressure

KVL Crankcase pressure regulator at a fall in pressure on the outlet side 0.2 - 6 bar

KVC Capacity regulator at a fall in pressure on the outlet side 0.2 - 6 bar

CPCE Capacity regulator at a fall in pressure on the outlet side 0 - 6 bar

NRD Diﬀerential pressure regulator Begins to open when the pressure drop in the

3 - 20 bar valve is 1.4 bar, and is fully open when the pressure drop is 3 bar.

KVD Receiver pressure regulator at a fall in pressure on the outlet side 3 - 20 bar

Fitters notes Water valves

Contents Page

Application. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Identiﬁcation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Spare parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Water valves

Notes

46 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Water valves

Application

Identiﬁcation

WV pressure-operated water valves are used in refrigeration systems with water-cooled condensers to maintain constant condensing pressure under varying loads.

The water valves can be used for common refrigerants provided the operating range of the valves is not exceeded. The WVS can be used for R717 (ammonia)

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Danfoss water valve type WVFM consists of a valve body and bellows housing. The bellows housing carries a label giving valve type, operating range and max. permissible working pressure.

The label also indicates the max. permissible working pressure on the water side, given as PN 10 in accordance with IEC 534-4. The direction in which the setting spindle must be turned for greater or lesser water quantity is given at the bottom of the valve.

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Water valve type WVFX consists of a valve body with setting unit on one side and a bellows housing on the other.

The bellows housing carries a label giving valve type, operating range and permissible working pressure.

All pressures given apply to the condenser side. Moulded in on one side of the valve body are PN 16 (nom. pressure) and, for example, DN 15 (nom. diameter), together with kvs 1.9 (valve capacity in m3/h at a pressure drop of 1 bar).

RA and DA are moulded in on the opposite side of the valve body.

RA means “reverse acting” and DA means “direct acting”.

When WVFX is used as a condensing pressure valve the bellows housing must always be mounted nearest the DA marking.

Water valves

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Fitters notes Water valves

Installation

WVFM and WVFX are installed in the water line, normally ahead of the condenser, with ﬂow in the direction of the arrow.

It is a good idea to always install an FV ﬁlter ahead of the water valve to exclude dirt from the moving parts of the valve.

To prevent vibrations from being transmitted to the bellows housing the housing must be connected to the discharge line after the oil separator, via a capillary tube.

The capillary tube must be connected to the top side of the discharge line to prevent the backﬂow of oil and perhaps dirt.

WVFM and WVFX 32-40 water valves are normally installed with bellows housing upwards.

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Setting

WVFX 10-25 water valves can be installed in any position.

WVFM and WVFX water valves must be set to obtain the required condensing pressure. Turning the setting spindle clockwise gives lower pressure, turning it counterclockwise gives higher pressure.

The scale marks 1 - 5 can be used for coarse setting. Scale mark 1 corresponds to about 2 bar, and scale mark 5 corresponds to about 17 bar.

Note that the valve setting range is given for when the valve begins to open. The condensing pressure must increase by 3 bar to fully open the valve.

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48 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Water valves

Maintenance

It is a good idea to include water valves in preventive maintenance because dirt (sludge) can collect around the moving parts of the valves.

The maintenance routine can include ﬂushing the water valves, partly to wash out impurities and partly to be able to “sense” whether the reaction of valves has become slower.

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Flushing a WVFM water valve is easiest to perform if two screwdrivers are inserted under the setting screw.

The screw can then be levered up to give greater water ﬂow.

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WVFX valves can be ﬂushed similarly using two screwdrivers inserted in the slots on each side of the setting unit (spring housing) and under the spring cup.

Levering the screwdrivers down towards the piping gives greater water ﬂow.

If operating irregularities appear in a water valve, or if leakage occurs across the valve seat, dismantle the valve and clean it.

Before dismantling a valve, the pressure must always be relieved from the bellows housing, i.e. it must be disconnected from the refrigeration system condenser.

Before dismantling, screw the setting spring fully clockwise towards the lowest pressure setting. The O-ring and remaining seals must always be replaced after dismantling.

Water valves

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Ag0_0012

Fitters notes Water valves

Spare parts

Spare parts for WVFM and WVFX water valves can be obtained from Danfoss:

one bellows housing. one service kit (containing spare parts,

gaskets and grease for the water side of the valve).

A gasket set is also supplied as a spare part for type WVFM.

The code numbers of spare parts and gasket sets are given in the spare parts catalogue*.

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*) Find spare part documentation on http://www.danfoss.com

50 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Filter driers & sight glasses

Contents Page

Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Filter drier selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Location in refrigeration system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Soldering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Replace the ﬁlter drier when . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

DCR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Using gaskets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Mounting gaskets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Disposal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Filter drier replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Special ﬁlters from Danfoss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Combidriers type DCC and DMC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Burn-out ﬁlter, type 48-DA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Special application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

DCL/DML ﬁlter driers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Dimensioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

EPD (Equilibrium Point Dryness) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Drying capacity (water capacity). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Liquid capacity (ARI 710*) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Recommended system capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Filter driers from Danfoss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Filter driers &

sight glasses

Notes

52 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Filter driers & sight glasses

Function

To ensure optimum function the refrigeration system must be internally clean and dry.

Before starting the system, moisture must be removed by evacuation at a max. pressure of 0.05 mbar abs.

During operation, dirt and moisture must be collected and removed. This is performed by a ﬁlter drier containing a solid core consisting of:

Molecular Sieves Silica gel (low eﬀectiveness - not used in

Danfoss driers) Activated aluminium oxide and a polyester

mesh A inserted in the ﬁlter outlet.

DML: 100% Molecular Sieves DCL: 80% Molecular Sieves 20% Activated aluminium

The solid core can be compared to a sponge’s ability to soak up water and retain it.

Molecular Sieves retain water, whereas activated aluminium oxide retains water and acids.

The solid core B together with the polyester mat A also acts as a dirt ﬁlter.

The solid core retains large dirt particles and the polyester mat small ones.

The ﬁlter drier is thus able to collect all dirt particles larger than 25 micron.

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Filter drier selection

The ﬁlter drier must be selected to suit the connections and the capacity of the refrigeration system.

If a ﬁlter drier with solder connections is required, a Danfoss type DCL/DML ﬁlter drier can be used to advantage. It has an extra-high drying capacity which prolongs the interval between replacements.

A collar on the connector A indicates that the connection is a mm size. If the connector A is plain, i.e. no collar, the connector is an inch size. Type DCL can be used for CFC/HCFC refrigerants. Type DML can be used for HFC refrigerants. See page 60 for more details.

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Ah0_0018

Filter driers &

sight glasses

Fitters notes Filter driers & sight glasses

Location in refrigeration system

The ﬁlter drier is normally installed in the liquid line where its primary function is to protect the expansion valve.

The velocity of the refrigerant in the liquid line is low and therefore contact between the refrigerant and the solid core in the ﬁlter drier is good. At the same time, the pressure drop across the ﬁlter drier is low.

A ﬁlter drier can also be installed in the suction line where its task is to protect the compressor against dirt and dry the refrigerant.

Suction ﬁlters, so-called “burn-out” ﬁlters, are used to remove acids after motor damage. To ensure low pressure drop, a suction ﬁlter must normally be larger than a liquid line ﬁlter.

A suction ﬁlter must be replaced before the pressure drop exceeds the following values:

A/C systems: 0.50 bar Refrigeration systems: 0.25 bar Freezing systems: 0.15 bar

A sight glass with moisture indicator is normally installed after the ﬁlter drier, where the sight glass indication means: Green: No dangerous moisture in the refrigerant. Yellow: Moisture content too high in the refrigerant ahead of the expansion valve.

Bubbles:

1) Pressure drop across the ﬁlter drier too high.

2) No subcooling.

3) Insuﬃcient refrigerant in whole system.

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If the sight glass is installed ahead of the ﬁlter drier the indication is: Green: No dangerous moisture in the refrigerant. Yellow: Moisture content in the whole refrigeration system too high.

The changeover point from green to yellow in the sight glass indicator is determined by the water solubility of the refrigerant.

Note:

The changeover points in Danfoss sight glasses are very small. This ensures that a switch to green in the indicator only occurs when the refrigerant is dry.

Bubbles:

1) No subcooling.

2) Insuﬃcient refrigerant in whole system.

Note!

Do not replenish refrigerant solely because of bubbles in the sight glass. First ﬁnd out the cause of the bubbles!

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Ah0_0031

Ah0_0006

54 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Filter driers & sight glasses

Installation

The ﬁlter drier must be installed with ﬂow in the direction of the arrow on the ﬁlter drier label.

The ﬁlter drier can have any orientation, but the following must be remembered:

Vertical mounting with downward ﬂow means rapid evacuation/emptying of the refrigeration system.

With vertical mounting and upward ﬂow, evacuation/emptying takes longer because refrigerant must be evaporated out of the ﬁlter drier.

The ﬁlter core is ﬁrmly ﬁxed in the ﬁlter housing. Danfoss ﬁlter driers are therefore able to resist vibration up to 10 g*).

Find out whether the tubing will support the ﬁlter drier and resist vibration. If not, the ﬁlter drier must be installed using a clamping band or similar secured to a rigid part of the system.

*) 10 g = Ten times the gravitational force of the earth.

For DCR: Install with the inlet connector upwards or horizontal.

This avoids collected dirt running out into the tubing when the core is replaced.

When installing a new DCR, remember that there must always be suﬃcient space for core replacement.

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Do not unpack ﬁlter driers or cores until immediately before installation. This will safe-guard the items in the best possible way.

There is neither vacuum nor overpressure in ﬁlters or cans.

Plastic union nuts, capsolutes and the hermetically sealed can guarantee completely “fresh” desiccants.

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Filter driers &

sight glasses

Fitters notes Filter driers & sight glasses

Soldering

Operation

Protective gas, e.g. N2, should be used when soldering the ﬁlter drier.

Ensure that the protective gas ﬂows in the direction of ﬁlter ﬂow. This avoids heat from soldering being damaging the polyester mesh.

Soldering alloys and ﬂux give oﬀ fumes that can be hazardous. Read supplier instructions and observe their safety stipulations. Keep your head away from the fumes during soldering.

Moisture enters the system:

1) When the refrigeration system is being built up.

2) When the refrigeration system is opened for servicing.

3) If leakage occurs on the suction side, if it is under vacuum.

4) When the system is ﬁlled with oil or refrigerant containing moisture.

5) If leakage occurs in a water-cooled condenser. Moisture in the refrigeration system can cause:

a) Blockage of the expansion device because of ice formation. b) Corrosion of metal parts. c) Chemical damage to the insulation in hermetic and semihermetic compressors. d) Oil breakdown (acid formation).

The ﬁlter drier removes moisture that remains after evacuation or that subsequently enters the refrigeration system.

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Use strong ventilation and/or extraction at the ﬂame so that you do not inhale fumes and gases. Use protective goggles. Use wet cloth around ﬁlter driers with pure copper connectors.

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Warning! Never use “antifreeze liquids” like methyl alcohol together with a ﬁlter drier. Such liquid can damage the ﬁlter so that it is unable to absorb water and acid.

Replace the ﬁlter drier when

1. The sight glass indicates that the moisture content is too high (yellow).

2. Pressure drop across the ﬁlter is too high (bubbles in sight glass during normal operation).

3. A main component in the refrigerant system has been replaced, e.g. the compressor.

4. Each time the refrigeration system is otherwise opened, e.g. if the oriﬁce assembly in an expansion valve is replaced.

Never re-use a used ﬁlter drier. It will give oﬀ moisture if it is used in a refrigeration system with low moisture content, or if it becomes heated.

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56 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Filter driers & sight glasses

DCR

Using gaskets

Mounting gaskets

Note, there can be overpressure in the ﬁlter. Therefore be careful when opening the ﬁlter.

Never re-use the ﬂange gasket in the DCR ﬁlter. Fit a new gasket and smear it with a little refri-

geration machine oil before tightening.

Only use undamaged gaskets. Flange surfaces that are to form the seal must

be faultless, clean and dry before mounting. Do not use adhesive ﬁller, rust remover

or similar chemicals when mounting or dismantling.

1. Moisten gasket surfaces with a drop of refrigerant oil.

2. Put gasket in place.

3. Mount bolts and tighten slightly until all bolts have made good contact.

4. Cross-tighten bolts.

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Use suﬃcient oil for lubricating bolts and screws during mounting.

Do not use bolts which are dry, corroded or defective in any other way (defective bolts can give incorrect tightening which may result in leaking ﬂange joints).

Tighten bolts in at least 3-4 steps, e.g. as follows: Step 1: to approx. 10% of required torque.

Step 2: to approx. 30% of required torque. Step 3: to approx. 60% of required torque. Step 4: to 100% of required torque.

Finally, check that the torque is correct in the same order as used when tightening.

Disposal

Filter drier replacement

Always seal used ﬁlter driers. They contain small amounts of refrigerant and oil residue.

Observe authority requirements when scrapping used ﬁlter driers.

Close valve no. 1. Suck the ﬁlter empty. Close valve no. 4. Close valve no. 2.

The system will now operate, bypassing the ﬁlter.

Replace ﬁlter or ﬁlter core. Evacuate the ﬁlter drier via a schrader valve

(no. 3). Restart the system by opening/closing the

valves in the reverse order. Remove any levers/handwheels from the

valves.

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Ah0_0014

Filter driers &

sight glasses

Fitters notes Filter driers & sight glasses

Special ﬁlters from Danfoss

Combidriers type DCC and DMC

Burn-out ﬁlter, type 48-DA

Combidriers type DCC and DMC are used in smaller systems with expansion valve where the condenser cannot contain the entire quantity of refrigerant.

The receiver in the combidrier increases liquid subcooling and creates the possibility of automatic defrost on pumpdown. The receiver takes up varying refrigerant volume (from varying condensing temperature) and must be able to contain the whole refrigerant quantity during service and repair.

In the interests of safety, the volume of the receiver must be at least 15% greater than the refrigerant volume.

Burn-out ﬁlter, type 48-DA, is for use after a hermetic or semihermetic compressor has suﬀered damage.

Compressor damage that gives rise to acid formation will be revealed by oil odour and perhaps discolouration. Damage can occur because of:

moisture, dirt or air defective starter refrigerant failure because of too small a

refrigerant charge, hot gas temperature higher than 175°C

Ah0_0012

Ah0_0013

After replacing the compressor and cleaning the remainder of the system, two burn-out ﬁlters are installed; one in the liquid line and one in the suction line.

The acid content is then checked regularly and the ﬁlters replaced as necessary.

When an oil check shows that the system no longer contains acid, the burn-out ﬁlter in the liquid line can be replaced by an ordinary ﬁlter drier. The burn-out ﬁlter core in the

suction line can be removed.

Ah0_0010

Special application

DCL/DML ﬁlter driers

Type DCL/DML 032s, DCL/DML 032.5s and DCL/DML 033s are manufactured specially for capillary tube systems and are therefore used in refrigeration systems where expansion is through

a capillary tube.

Ah0_0017

DCL/DML ﬁlter driers can also be used when reparing refrigerators and freezers, etc. Both time and money can be saved by installing a DCL/DML ﬁlter drier in the suction line.

The advantage of doing so can best be illustrated by comparing the normal repair procedure for a defective compressor with a method that exploits the good characteristics of the DCL/DML ﬁlter in retaining moisture, acid and dirt.

NOTE: The „DCL/DML method“ can only be used when the oil is not discoloured and when the pencil ﬁlter is not clogged.

Ah0_0015

58 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Filter driers & sight glasses

Special application

DCL/DML ﬁlter driers (cont.)

Dimensioning

The advantages gained by installing a DCL/DML ﬁlter in the suction line are:

1. Faster repair.

2. Increased drying and acid capacity.

3. Protection of the compressor against impurities of every kind.

4. Better quality of repair.

5. Cleaner working environment. The acid and moisture bound in the old oil will be

absorbed by the DCL/DML ﬁlter. Therefore it is not necessary to remove remaining

oil from the refrigeration system.

A DCL/DML in the suction line retains impurities from condenser, evaporator, tubing, etc. and thereby prolongs the life of the new compressor.

DCL/DML ﬁlters having the same connections as the compressor can be used. The Danfoss range of hermetic compressors can also be recommended.

When choosing ﬁlter driers from catalogues there are several expressions each of which can form the basis of selection.

Procedure with pencil ﬁlter Procedure with

Recover refrigerant and evaluate for re-use

Remove compressor + pencil ﬁlter

Remove oil residue in system Nothing

Dry system with nitrogen Nothing

Connect new compressor and ﬁt new pencil ﬁlter

Evaluate and change refrigerant

DCL/DML ﬁlter

Recover refrigerant and evaluate for re-use

Remove compressor

Connect new compressor and ﬁt DCL/DML ﬁlter in suction line

Evaluate and change refrigerant

Example:

Compressor type Suction tube

TL Ø6.2 DCL/DML 032s NL 6-7 Ø6.2 DCL/DML 032s

[mm]

Filter type

EPD (Equilibrium Point Dryness)

Drying capacity (water capacity)

Liquid capacity (ARI 710*)

Deﬁnes the least possible water content in a refrigerant in its liquid phase, after it has been in contact with a ﬁlter drier.

EPD for R22 = 60 ppmW *) EPD for R410A = 50 ppmW *) EPD for R134a = 50 ppmW *) EPD for R404A / R507 / R407C = 50 ppmW *)

As stipulated by ARI 710, in ppmW (mg

/kg

water

*) ARI: Air-conditioning and Refrigeration Institute, Virginia, USA

refrigerant

)

The quantity of water the ﬁlter drier is able to absorb at 24°C and 52°C liquid temperature, as stipulated by the ARI 710* standard.

The drying capacity is given in grams of water, drops of water or kg refrigerant on drying out.

R22: 1050 ppmW to 60 ppmW R410A: 1050 ppmW to 50 ppmW R134a: 1050 ppmW to 50 ppmW R404A / R507 / R407C: 1020 ppmW to 50 ppmW

1000 ppmW = 1 g water in 1 kg refrigerant 1 g water = 20 drops.

Gives the quantity of liquid able to ﬂow through a ﬁlter with a pressure drop of 0.07 bar at tc = +30°C, te = -15°C.

The liquid capacity is stated in l/min or in kW. Conversion from kW to litres/minute:

R22 / R410A 1kW = 0.32 l/min R134a 1kW = 0.35 l/min R404A / R507 / R407C 1kW = 0.52 l/min

*) ARI: Air-conditioning and Refrigeration Institute, Virginia, USA

Ah0_0025

Ah0_0016

Ah0_0024

Filter driers &

sight glasses

Fitters notes Filter driers & sight glasses

Recommended system capacity

Filter driers from Danfoss

Operating conditions:Stated in kW for diﬀerent types of refrigeration systems on the basis of a liquid capacity of ∆p = 0.14 bar and typical operating conditions.

Refrigeration and freezing systems

A/C systems A/C units

te = evaporating temperature

tc = condensing temperature

te = -15°C, tc = +30°C

te = -5°C, tc = +45°C te = +5°C, tc = +45°C

Warning:

With the same system capacity in kW for A/C units and for refrigeration/freezing systems, smaller ﬁlter driers can be installed in A/C units because of higher evaporating temperature (te) and the assumption that factory produced units contain less moisture than systems built up „on site“.

Product type Function Refrigerant Core Oil type

DML Standard ﬁlter drier HFC, compatible with

DCL Standard ﬁlter drier CFC/HCFC 80% molecular sieves

DMB Bi-ﬂow ﬁlter drier HFC, compatible with

DCB Bi-ﬂow ﬁlter drier CFC/HCFC 80% molecular sieves

DMC Combi ﬁlter drier HFC, compatible with

DCC Combi ﬁlter drier CFC/HCFC 80% molecular sieves

DAS Burn-out ﬁlter drier R22, R134a,

DCR Filter drier with ex-

48-DU/DM for DCR

48-DN/DC for DCR

48-DA for DCR

48-F for DCR

changeable core

Exchangeable core for DCR: std. ﬁlter drier

Exchangeable core for DCR with exchangeable ﬁlter insert

R22

R404A, R507

See core description below

HFC, compatible with R22

CFC/HCFC 80% molecular sieves

R22, R134a, R404A, R507

All - All

100% molecular sieves Polyolester (POE)

20% activated alumina

100% molecular sieves Polyolester (POE)

20% activated alumina

100% molecular sieves Polyolester (POE)

20% activated alumina

30% molecular sieves 70% activated alumina

48-DU/DM, 48-DN DC, 48-DA, 48-F

100% molecular sieves Polyolester (POE)

20% activated alumina

Polyalkyl (PAG)

Mineral oil (MO) Alkyl benzene (BE)

Polyalkyl (PAG)

Mineral oil (MO) Alkyl benzene (BE)

Polyalkyl (PAG)

Mineral oil (MO) Alkyl benzene (BE)

Polyalkyl (PAG)

Mineral oil (MO) Alkyl benzene (BE)

60 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Danfoss compressors

Page

This chapter is divided into four sections:

Mounting instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Condensing units in general . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Repair of hermetic refrigeration systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Practical application of refrigerant R290 propane in small hermetic systems . . . . . . . . . . . . . . . . . . . . . . . 115

compressors

Danfoss

Fitters notes Danfoss compressors - Mounting Instructions

Contents Page

1.0 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

2.0 Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

2.1 Denomination. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

2.2 Low and High starting torque. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

2.3 Motor protector and winding temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

2.4 Rubber grommets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

2.5 Minimum ambient temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

3.0 Fault ﬁnding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

3.1 Winding protector cut-out. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

3.2 PTC and protector interaction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

3.3 Check of winding protector and resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

4.0 Opening the refrigeratingsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

4.1 Flammable refrigerants. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

5.0 Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

5.1 Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

5.2 Drifting out connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

5.3 Tube adapters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

5.4 Solders. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

5.5 Soldering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

5.6 Lokring connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

5.7 Driers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

5.8 Driers and refrigerants. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

5.9 Capillary tube in drier. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

6.0 Electrical equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

6.1 LST starting device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

6.2 HST starting equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

6.3 HST CSR starting equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

6.4 Equipment for SC twincompressors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

6.5 Electronic unit for variable speed compressors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

7.0 Evacuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

7.1 Vacuum pumps. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

8.0 Charging of refrigerant. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

8.1 Maximum refrigerant charge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

8.2 Closing the process tube. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

9.0 Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

9.1 Testing of the appliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

compressors

Danfoss

Notes

64 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Danfoss compressors - Mounting Instructions

1.0 General

2.0 Compressor

When a compressor has to be installed in new appliances normally suﬃcient time is available to choose the right compressor type from datasheets and make suﬃcient testing. Contrary when a faulty compressor has to be replaced it can in many cases be impossible to get the same compressor type as the original. In such cases it is necessary to compare relevant compressor catalogue data.

Long lifetime for a compressor can be expected if the service work is done in the right way and cleanness and dryness of the components are taken into consideration.

The programme of Danfoss compressors consists of the basic types P, T, N, F, SC and SC Twin.

Danfoss 220 V compressors have a yellow label with information of the type designation, voltage and frequency, application, starting conditions, refrigerant and code number.

The 115 V compressors have a green label. LST/HST mentioned both means that the starting

characteristics are depending on the electrical equipment.

The service technician has to observe the following when choosing a compressor. Type of refrigerant, voltage and frequency, application range, compressor displacement/ capacity, starting con-ditions and cooling conditions.

If possible use the same refrigerant type as in the faulty system.

2.1 Denomination

If the type label has been destroyed, the compressor type and the code number can be found in the stamping on the side of the compressor. See ﬁrst pages in collection of datasheets for the compressor.

Example of compressor denomination

T L E S 4 F K

Basic design (P, T, N, F, S)

L, R, C = int. motor protection T, F = ext. motor protection LV = variable speed

E = energy optimization Y = High energy optimization

S = semi direct suction

Nominal displacement in cm

A = LBP / (MBP) R12 AT = LBP (tropical) R12 B = LBP / MBP / HBP R12 BM = LBP (240 V) R22 C = LBP R502 / (R22) CL = LBP R404A/ R507 CM = LBP R22 / R502 CN = LBP R290 D = HBP R22

DL = HBP R404A/ R507 F = LBP R134a FT = LBP (tropical) R134a G = LBP/MBP/HBP R134a GH = Heat pumps R134a GHH = Heat pumps (optimized) R134a H = Heat pumps R12 HH = Heat pumps (optimized) R12 K = LBP/(MBP) R600a KT = LBP (tropical) R600a MF = MBP R134a ML = MBP R404A/R507

Am0_0024

Am0_0025

empty = LST / HST K = Capillary tube (LST) X = Expansion valve (HST)

compressors

Danfoss

Fitters notes Danfoss compressors - Mounting Instructions

3327-

Com

ressor bas

ommet sleeve

Washer

Nut M6

Cabinet base

Screw M6 x 25

Rubber grommet

2.1 Denomination (cont.)

2.2 Low and High starting torque

The ﬁrst letter of the denomination (P, T, N, F or S) indicates compressor series whereas the second letter indicates motor protection placing.

E, Y and X mean diﬀerent energy optimization steps. S means semi direct suction. V means variable speed compressors. On all these mentioned types the indicated suction connector has to be used. Using the wrong connector as suction connector will lead to reduced capacity and eﬃciency.

A number indicates the displacement in cm3, but for PL compressors the number indicates the nominal capacity.

The letter after the displacement indicates which refrigerant must be used as well as the ﬁeld of application for the compressor. (See example) LBP (Low Back Pressure) indicates the range of low evaporating temperatures, typically -10°C down to -35°C or even -45°C,for use in freezers and refrigerators with freezer compartments.

MBP (Medium Back Pressure) indicates the range of medium evaporating temperatures, typically

Description of the diﬀerent electrical equipments shown can be found in the datasheets for the compressors. See also section 6.0.

Low starting torque (LST) compressors must only be used in refrigerating systems having capillary tube throttling device where pressure equalization is obtained between suction and discharge sides during each standstill period.

A PTC starting device (LST) requires that the standstill time is at least 5 minutes, since this is the time necessary for cooling the PTC.

The HST starting device, which gives the compressor a high starting torque, must always

-20°C up to 0°C, such as in cold cabinets, milk

coolers, ice machines and water coolers.

HBP (High Back Pressure) indicates high

evaporating temperatures, typically -5°C up to

+15°C, such as in dehumidiﬁers and some liquid

coolers.

T as extra character indicates a compressor

intended for tropical application. This means high

ambient temperatures and capability of working

with more unstable power supply.

The ﬁnal letter in the compressor denomination

provides information on the starting torque. If,

as principal rule, the compressor is intended for

LST (Low Starting Torque) and HST (High Starting

Torque), the place is left empty. The starting

characteristics are depending on the electrical

equipment chosen.

K indicates LST (capillary tube and pressure

equalization during standstill) and X

indicates HST (expansion valve or no pressure

equalization).

be used in refrigeration systems with expansion

valve, and for capillary tube systems without full

pressure equalization before each start.

High stating torque (HST) compressors are

normally using a relay and starting capacitor as

starting device.

The starting capacitors are designed for short

time cut-in.

“1.7% ED”, which is stamped onto the starting

capacitor, means for instance max. 10 cut-ins per

hour each with a duration of 6 seconds.

2.3 Motor protector and winding temperature

2.4 Rubber grommets

Most of the Danfoss compressors are equipped with a built-in motor protector (winding protector) in the motor windings. See also section 2.1.

Stand the compressor on the base plate until it is ﬁtted.

This reduces the risk of oil coatings inside the connectors and associated brazing problems.

Place the compressor on its side with the connectors pointing upwards and then ﬁt the rubber grommets and grommet sleeves on the base plate of the compressor.

Do not turn the compressor upside down. Mount the compressor on the baseplate of the

appliance.

At peak load the winding temperature must

not exceed 135°C and at stable conditions the

winding temperature must not exceed 125°C.

Speciﬁc information on some special types can

be found in the collection of data sheets.

Am0_0026

Am0_0027

66 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Danfoss compressors - Mounting Instructions

M S

Start winding

Winding protector

Main winding

2.5 Minimum ambient temperature

3.0 Fault ﬁnding

3.1 Winding protector cut-out

3.2 PTC and protector interaction

3.3 Check of winding protector and resistance

Allow the compressor to reach a temperature above 10°C before starting the ﬁrst time to avoid starting problems.

If the compressor does not operate, it could have many reasons. Before replacing the compressor, it should be made sure, that it is defect.

If the winding protector cuts out while the compressor is cold, it can take approx 5 minutes for the protector to reset.

The PTC starting unit requires a cooling time of 5 minutes before it can restart the compressor with full starting torque.

Short time power supply cut oﬀs, not long enough to allow the PTC to cool down, can result in start failure for up to 1 hour.

The PTC will not be able to provide full action during the ﬁrst protector resets, as they typically

In the event of compressor failure a check is made by means of resistance measurement directly on the current lead-in to see whether the defect is due to motor damage or simply a temporarily cut out of the winding protector.

If tests with resistance measurement reveal a connection through the motor windings from point M to S of the current lead-in, but broken circuit between point M and C and S and C this indicates that the winding protector is cut out. Therefore, wait for resetting.

For easy failure location, please see the section “Trouble shooting”.

If the winding protector cuts out while the compressor is warm (compressor housing above 80°C) the resetting time is increased. Up to approx 45 minutes may pass before reset.

do not allow pressure equalization also. Thus the protector trips until the reset time is long enough.

This mismatch condition can be solved by unplugging the appliance for 5 to 10 minutes typically.

Am0_0028

4.0 Opening the refrigerating system

Never open a refrigerating system before all components for the repair are available.

Compressor, drier and other system components must be sealed oﬀ until a continuous assembly can occur.

Opening a defect system must be done in diﬀerent ways depending on the refrigerant used.

Fit a service valve to the system and collect the refrigerant in the right way.

If the refrigerant is ﬂammable it can be released outside in the open air through a hose if the amount is very limited.

Then ﬂush the system with dry nitrogen.

compressors

Danfoss

Fitters notes Danfoss compressors - Mounting Instructions

TLS

4.1 Flammable refrigerants

R600a and R290 are hydrocarbons. These refrigerants are ﬂammable and are only allowed for use in appliances which fulﬁl the requirements laid down in the latest revision of EN/IEC 603352-24. (To cover potential risk originated from the use of ﬂammable refrigerants).

Consequently, R600a and R290 are only allowed

to be used in household appliances designed for

this refrigerant and fulﬁl the above-mentioned

standard. R600a and R290 are heavier than air

and the concentration will always be highest at

the ﬂoor. The ﬂammability limits are approx. as

follows:

Refrigerant R600a R290 Lower limit 1.5% by vol. (38 g/m3) 2.1% by vol. (39 g/m3) Upper limit 8.5% by vol. (203 g/m3) 9.5% by vol. (177 g/m3) Ignition temperature 460°C 470°C

In order to carry out service and repair on R600a and R290 systems the service personnel must be properly trained to be able to handle ﬂammable refrigerants.

This includes knowledge on tools, transportation of compressor and refrigerant, and the relevant regulations and safety precautions when carrying out service and repair.

Do not use open ﬁre when working with refrigerants R600a and R290!

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Danfoss compressors for the ﬂammable refrigerants R600a and R290 are equipped with a yellow warning label as shown.

The smaller R290 compressors, types T and N, are LST types. These often need a timer to ensure suﬃcient pressure equalization time.

For further information, please see the section “Practical Application of Refrigerant R290 Propane in Small Hermetic Systems”.

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5.0 Mounting

Soldering problems caused by oil in the connectors can be avoided by placing the compressor on its base plate some time before

The compressor must never be placed upside

down. The system should be closed within 15

minutes to avoid moisture and dirt penetration. soldering it into the system.

5.1 Connectors

The positions of connectors are found in the sketches. “C” means suction and must always be connected to the suction line. “E” means discharge and must be connected to the discharge line. “D” means process and is used for processing the system.

68 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

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Fitters notes Danfoss compressors - Mounting Instructions

5.1 Connectors (cont.)

Most Danfoss compressors are equipped with tube connectors of thick-walled, copper-plated steel tube which have a solderability which comes up to that of conventional copper connectors.

The connectors are welded into the compressor housing and weldings cannot be damaged by overheating during soldering.

The connectors have an aluminium cap sealing (capsolut) which gives a tight sealing. The sealing secures that the compressors have not been opened after leaving Danfoss’ production lines. In addition to that, the sealing makes a protecting charge of nitrogen superﬂuous.

The capsoluts are easily removed with an ordinary pair of pliers or a special tool as shown. The capsolut cannot be remounted. When the seals on the compressor connectors are removed the compressor must be mounted in the system within 15 minutes to avoid moisture and dirt penetration.

Capsolut seals on connectors must never be left in the assembled system.

Oil coolers, if mounted (compressors from 7 cm3 displacement), are made of copper tube and the tube connectors are sealed with rubber plugs. An oil-cooling coil must be connected in the middle of the condenser circuit.

SC Twin compressors must have a non-return valve in the discharge line to compressor no. 2. If a change in the starting sequence between compressor no.1 and no. 2 is wanted a non-return valve has to be placed in both discharge lines.

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In order to have optimum conditions for soldering and to minimize the consumption of soldering material, all tube connectors on Danfoss compressors have shoulders, as shown.

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compressors

Danfoss

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70 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Danfoss compressors - Mounting Instructions

5.2 Drifting out connectors

It is possible to drift out the connectors having inside diameters from 6.2 mm to 6.5 mm which suit 1⁄4” (6.35 mm) tube, but we advise against drifting out the connectors by more than 0.3 mm.

During drifting it is necessary to have a suitable counterforce on the connectors so that they don’t break oﬀ .

A diﬀ erent solution to this problem would be to reduce the diameter of the end of the connector tube with special pliers.

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5.3 Tube adapters

Instead of drifting out the connectors or reducing the diameter of the connection tube, copper adapter tubes can be used for service. A 6/6.5 mm adapter tube can be used where a compressor with millimetre connectors (6.2 mm) is to be connected to a refrigerating system with 1⁄4” (6.35 mm) tubes.

A 5/6.5 mm adapter tube can be used where a compressor with a 5 mm discharge connector is to be connected to a 1⁄4” (6.35 mm) tube.

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5 ø ±

1 .

3 ø

± 1

. 0

. 6

ø ±

9 0

. 0

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5.4 Solders

For soldering the connectors and copper tubes solders having a silver content as low as 2% can be used. This means that the so-called phosphor solders can also be used when the connecting tube is made of copper.

If the connecting tube is made of steel, a solder with high silver content which does not contain phosphor and which has a liquidus temperature below 740°C is required. For this also a ﬂ ux is needed.

Danfoss

compressors

Fitters notes Danfoss compressors - Mounting Instructions

5.5 Soldering

The following are guidelines for soldering of steel connectors diﬀ erent from soldering copper connectors.

During heating, the temperature should be kept as close to the melting point of the solder as possible.

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Use the “soft” heat in the torch ﬂ ame when heating the joint.

Distribute the ﬂ ame so at least 90% of the heat concentrates around the connector and approx. 10% around the connecting tube.

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When the connector is cherry-red (approx. 600°C) apply the ﬂ ame to the connecting tube for a few seconds.

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Continue heating the joint with the “soft” ﬂ ame and apply solder.

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Overheating will lead to surface damage, so decreasing the chances of good soldering.

Draw the solder down into the solder gap by slowly moving the ﬂ ame towards the compressor; then completely remove the ﬂ ame.

Fitters notes Danfoss compressors - Mounting Instructions

5.6 Lokring connections

System containing the ﬂammable refrigerants R600a or R290 must not be soldered. In such cases a Lokring connection as shown can be used.

Newly made systems can be soldered as usual, as long as they have not been charged with ﬂammable refrigerant.

Assembly jaws

Bolt

Tool

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Charged systems are never to be opened by use

of the ﬂame. Compressors from systems with

ﬂammable refrigerant have to be evacuated to

remove the refrigerant residues from the oil.

Tube LOKRING LOKRING Joint

Before the assembly

Tube LOKRING LOKRING TubeJoint

LOKRING union joint

After the assembly

5.7 Driers

Danfoss compressors are expected used in welldimensioned refrigerant systems including a drier containing an adequate amount and type of desiccant and with a suitable quality.

The refrigerating systems are expected to have a dryness corresponding to 10 ppm. As a max limit 20 ppm is accepted.

The drier must be placed in a way ensuring that the direction of ﬂow of the refrigerant follows gravitation.

Thus the MS beads are prevented from moving among themselves and in this way making dust and possible blockage at the inlet of the capillary tube. At capillary tube systems this also ensures a minimal pressure equalizing time.

Especially pencil driers should be chosen carefully to ensure proper quality. In transportable systems only driers approved for mobile application are to be used.

A new drier must always be installed when a refrigeration system has been opened.

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Fitters notes Danfoss compressors - Mounting Instructions

5.8 Driers and refrigerants

Water has a molecular size of 2.8 Ångström. Accordingly, Molecular Sieves with a pore size of 3 Ångström will be suitable for normally used refrigerants.

MS with a pore size of 3 Ångström can be supplied by the following,

UOP Molecular Sieve Division (former Union Carbide) 25 East Algonquin Road, Des Plaines Illinois 60017-5017, USA 4A-XH6 4A-XH7 4A-XH9

R12, R22, R502 × × × R134a × × HFC/HCFC blends × R290, R600a × ×

Grace Davison Chemical W.R.Grace & Co, P.O.Box 2117, Baltimore Maryland 212203 USA “574” ”594”

R12, R22, R502 × × R134a × × HFC/HCFC blends × R290, R600a ×

CECA S.A La Defense 2, Cedex 54, 92062 Paris-La Defense France NL30R Siliporite H3R

R12, R22, R502 × × R134a × × HFC/HCFC blends × R290, R600a ×

5.9 Capillary tube in drier

Driers with the following amount of desiccants are recommended.

Compressor Drier PL and TL 6 gram or more FR and NL 10 gram or more SC 15 gram or more

Special care should be taken when soldering the capillary tube. When mounting the capillary tube it should not be pushed too far into the drier, thus touching the gaze or ﬁlter disc, causing a blockage or restriction. If, on the other hand, the tube is only partly inserted into the drier, blockage could occur during the soldering.

This problem can be avoided by making a “stop” on the capillary tube with a pair of special pliers as shown.

In commercial systems larger solid core driers are often used. These are to be used for the refrigerants according to the manufacturers instructions. If a burn-out ﬁlter is needed in a repair case, please contact the supplier for detail information.

compressors

Danfoss

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Fitters notes Danfoss compressors - Mounting Instructions

Winding protector

Star t winding

Main winding

1312

Main winding

Star t winding

Winding protector

Star t winding

Main winding

6.0 Electrical equipment

6.1 LST starting device

For information on the right starting devices, please see Datasheets for the compressor. Never use a starting device of and old compressor, because this may cause a compressor failure.

No attempt must be made to start the compressor without the complete starting

Compressors with internal motor protector.

The below drawings show three types of devices with PTC starters.

Mount the starting device on the current lead-in of the compressor.

Pressure must be applied to the centre of the starting device so that the clips are not deformed.

Mount the cord relief on the bracket under the starting device.

equipment. For safety reasons the compressor

must always be earthed or otherwise additionally

protected. Keep away inﬂammable material from

the electrical equipment.

The compressor must not be started under

vacuum.

On some energy optimized compressors a run

capacitor is connected across the terminals N and

S for lower power consumption.

Pressure must be applied to the centre of the

starting device when dismantling so that the

clips are not deformed.

Place the cover over the starting device and

screw it to the bracket.

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Fitters notes Danfoss compressors - Mounting Instructions

10 12

11 13

1 2

6.1 LST starting device (cont.)

Compressors with external motor protector.

The below drawings show equipment with relay and motor protector.

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Mounting of the relay is also done by applying pressure on the center of the relay. The cover is ﬁxed with a clamp.

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The below drawing shows equipment with PTC and external protector.

The protector is placed on the bottom terminal pin and the PTC on the 2 on the top.

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The cover is ﬁxed with a clamp. No cord relief is available for this equipment.

compressors

Danfoss

6.2 HST starting equipment

The next drawings show ﬁve types of devices with relays and starting capacitor.

Mount the starting relay on the current lead-in on the compressor. Apply pressure to the centre of the starting relay to avoid deforming the clips. Fasten the starting capacitor to the bracket on the compressor.

Mount the cord relief in the bracket under the starting relay. (Fig. A and B only).

Place the cover over the starting relay and screw it to the bracket or lock it in position with the locking clamp, or the integrated hooks.

Fitters notes Danfoss compressors - Mounting Instructions

1312

10 121113

1 1

2 2

6.2 HST starting equipment (cont.)

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Fitters notes Danfoss compressors - Mounting Instructions

2 N L

1 2

1 1

2 2 N N L

2 1

C D E

1 1

2 2 N N L L

2 N N L

2 1

C D E

6.3 HST CSR starting equipment

6.4 Equipment for SC twin compressors

Mount the terminal box on the current lead-in. Note that the leads must face upwards. Mount the cord relief in the bracket under terminal box. Place the cover. (See ﬁg. F).

The use of a time delay (e.g. Danfoss 117N0001) is recommended for starting the second section (15 seconds time delay).

If time delay is used, the connection on the terminal board between L and 1 must be removed from the compressor no. 2 connection box.

If thermostat for capacity control is used, the connection on the terminal board between 1 and 2 must be removed.

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A: Safety pressure control B: Time delay relay C: Blue D: Black E: Brown F: Remove wire L-1 if time delay is used Remove wire 1-2 if thermostat 2 is used

compressors

Danfoss

Fitters notes Danfoss compressors - Mounting Instructions

6.5 Electronic unit for variable speed compressors

7.0 Evacuation

The electronic unit provides the TLV and NLV compressors with a high starting torque (HST) which means that a pressure-equalization of the system before each start is not necessary.

The variable speed compressor motor is electronically controlled. The electronic unit has built-in overload protection as well as thermal protection. In case of activation of the protection the electronic unit will protect the compressor motor as well as itself. When the protection has

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After brazing, evacuation of the refrigeration system is started.

When a vacuum below 1 mbar is obtained the system is pressure equalized before the ﬁnal evacuation and charging of refrigerant.

If a pressure test has been performed directly before evacuation, the evacuation process is to be started smoothly, with low pumping volume, to avoid oil loss from the compressor.

Many opinions exist how evacuation can be carried out in the best way.

Dependent on the volume conditions of the suction and the discharge side in the refrigeration system, it might be necessary to choose one of the following procedures for evacuation.

One-sided evacuation with continuous evacuation until a suﬃciently low pressure in the condenser has been obtained. One or more short evacuation cycles with pressure equalization in between is necessary.

Two-sided evacuation with continuous evacuation until a suﬃciently low pressure has been obtained.

been activated, the electronic unit automatically will restart the compressor after a certain time.

The compressors are equipped with permanent magnet rotors (PM motor) and 3 identical stator windings. The electronic unit is mounted directly on the compressor and controls the PM motor.

Connecting the motor directly to AC mains, by fault, will damage the magnets and lead to drastically reduced eﬃciency, or even no functioning.

These procedures naturally require a good uniform quality (dryness) of the components used.

The below drawing shows a typical course of a one-sided evacuation from the process tube of the compressor. It also shows a pressure diﬀerence measured in the condenser. This can be remedied by increasing the numbers of pressure equalizations.

The dotted line shows a procedure where two sides are evacuated simultaneously.

When the time is limited, the ﬁnal vacuum to be obtained is only dependent on the capacity of the vacuum pump and the content of non condensable elements or refrigerant residues in the oil charge.

The advantage of a two-sided evacuation is that it is possible to obtain a considerably lower pressure in the system within a reasonable process time.

This implies that it will be possible to build a leak check into the process in order to sort out leaks before charging the refrigerant.

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Fitters notes Danfoss compressors - Mounting Instructions

7.0 Evacuation (cont.)

7.1 Vacuum pumps

8.0 Charging of refrigerant

The below drawing is an example of a preevacuation process with built-in leak test. The level of vacuum obtained depends on the process chosen. Two-sided evacuation is recommended.

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An explosion-safe vacuum pump must be used for systems with the ﬂammable refrigerants R600a and R290.

Always charge the system with type and amount of refrigerant recommended by the manufacturer. In most cases the refrigerant charge is indicated on the type label of the appliance.

The same vacuum pump can be used for all refrigerants if it is charged with Ester oil.

Charging can be done according to volume or by weight. Use a charging glass for charging by volume. Flammable refrigerants must be charged by weight.

8.1 Maximum refrigerant charge

8.2 Closing the process tube

If the max refrigerant charge is exceeded the oil in the compressor may foam after a cold start and the valve system could be demaged.

The refrigerant charge must never be too large to be contained on the condenser side of the refrigeration system. Only the refrigerant amount necessary for the system to function must be charged.

Compressor Maximum refrigerant charge

R134a R600a R290 R404A P 300 g 150 g T 400 g* 150 g 150 g 400 g N 400 g* 150 g 150 g 400 g F 900 g 150 g 850 g SC 1300 g 150 g 1300 g SC-Twin 2200 g

*) Single types with higher limits available, see data sheets.

For the refrigerants R600a and R290 the closing of the process tube can be done by means of a Lokring connection.

Soldering is not allowed on systems with ﬂammable refrigerants.

compressors

Danfoss

Fitters notes Danfoss compressors - Mounting Instructions

9.0 Testing

9.1 Testing of the appliance

Hermetic refrigerating systems must be tight. If a household appliance shall function over a reasonable lifetime, it is necessary to have leak rates below 1 gram per year. So leak test equipment of a high quality is required.

All connections must be tested for leaks with a leak testing equipment. This can be done with an electronic leak testing equipment.

The discharge side of the system (from discharge connector to the condenser and to the drier) must be tested with the compressor running.

Before leaving a system it must be checked that cooling down of the evaporator is possible and that the compressor operates satisfactory on the thermostat.

For systems with capillary tube as throttling device it is important to check that the system is able to pressure equalize during standstill periods and that the low starting torque compressor is able to start the system without causing trips on the motor protector.

The evaporator, the suction line and the compressor must be tested during standstill and equalized pressure.

If refrigerant R600a is used, leak test should be done with other means than the refrigerant, e.g. helium, as the equalizing pressure is low, so often below ambient air pressure. Thus leaks would not be detectable.

Fitters notes Danfoss compressors - Condensing units in general

Contents Page

General information on operating Danfoss condensing units. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Equipment conﬁguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Power supply and electrical equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Hermetic compressors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Condensers and fans. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Stop valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

ReceiverPressure container ordinance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Terminal box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Safety pressure monitors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Protective weather-resistant housing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Careful installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Contamination and foreign particles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Doing the pipe work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Tubing layout of the condensing units with 1-cylinder compressors

types TL, FR, NL,SC and SC-TWIN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Tubing layout of the condensing units with hermetic Maneurop®

reciprocating piston compressors, 1 -2-4 cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Leak check. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Soldering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Protective gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Evacuating and ﬁlling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Exceeding the max.allowable operational ﬁlling capacity and setting up outdoors. . . . . . . . . . . . . . . . . . 91

General information: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

“Pump-down switching“ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Max. allowable temperatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

compressors

Danfoss

Notes

Fitters notes Danfoss compressors - Condensing units in general

Danfoss

compressors

General information on operating Danfoss condensing units

In the following you will ﬁ nd general information and practical tips for using Danfoss condensing units. Danfoss condensing units represent an integrated range of units with Danfoss reciprocating piston compressors. The versions and conﬁ gurations of this series correspond to the requirements of the market. To give an overview of the program, the individual subsections are generally divided into the various hermetic compressors mounted on the condensing units.

Condensing units with 1-cylinder compressors (types TL, FR, NL, SC and SC-TWIN).

Condensing units with hermetic 1 -2 and 4 cylinder Maneurop® reciprocating piston compressors MTZ, NTZ and MPZ.

Programme:

Equipment conﬁ guration Danfoss condensing units are delivered with a

compressor and condenser mounted on rails or a base plate. Terminal boxes are prewired. In addition, stop valves, solder adaptors, collectors, dual pressure switches and power cables with 3-pin grounded plugs complete the delivery

kit. Please consult the corresponding Danfoss documentation or the current price list for details and ordering numbers. The Danfoss sales company responsible for your area will be glad to help you make your selection.

Power supply and electrical equipment

Condensing units with 1-cylinder compressors (types TL, FR, NL,SC and SC-TWIN) These condensing units are equipped with hermetic compressors and fans for 230 V 1-, 50 Hz power supply. The compressors are equipped with an HST starting device consisting of a starting relay and a starting capacitor. The components can also be delivered as spare parts. The starting capacitor is designed for short activation cycles (1.7 % ED). In practice, this means that the compressors can perform up to 10 starts per hour with an activation duration of 6 seconds.

Condensing units with hermetic 1 -2 and 4 cylinder Maneurop® reciprocating piston compressors MTZ and NTZ.

These condensing units are equipped with hermetic compressors and fan(s) for diﬀ erent voltage supplies:

400V-3ph-50 Hz for compressor and for fan(s). 400V-3ph-50Hz for compressor and 230V1ph-50Hz for fan(s) (the capacitor(s) of the fans are included inside the electrical box). 230V-3ph-50Hz for compressor and 230V1ph-50Hz for fan(s) (the capacitor(s) of the fans are included inside the electrical box). 230V-1ph-50Hz for compressor (the starting device (capcitors, relay) is included into the electrical box) and 230V-1ph-50Hz for fan(s)

The starting current of the Maneurop® threephase compressor can be reduced through the use of a soft starter. CI-tronicTM soft start, type MCI-C is recommended for use with this type of compressor. The starting current can be reduced up to 40 % depending on the compressor model and the model of soft start used. The mechanical load that occurs at start-up is also reduced, which increases the lifespan of the internal components.

For details on the CI-tronicTM MCI-C soft start, please contact your local Danfoss dealer. The number of compressor starts is limited to 12 per hour in normal conditions. Pressure equalisation is recommended when MCI-C is used.

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Fitters notes Danfoss compressors - Condensing units in general

Hermetic compressors The fully hermetically sealed compressor

types TL, FR, NL, SC and SC TWIN have a built-

in winding protector. When the protector is activated, a switch-oﬀ time of up to 45 minutes can occur as the result of heat storage in the motor.

The single-phase Maneurop® compressors MTZ and NTZ are internally protected by a

temperature/current sensing bimetallic protector, which senses the main and start winding currents and also the winding temperature.

The three-phase Maneurop® reciprocating piston compressors MTZ and NTZ are equipped against over-current and over-temperature by internal motor protection. The motor protection is located in the star point of the windings and opens all 3 phases simultaneously via a bimetallic disk. After the compressor has switched oﬀ via the bimetallic disc, reactivation can take up to 3 hours.

Condensers and fans Highly eﬀective condensers allow a broader

range of usage at higher ambient temperatures. One or two fan motors are used per condensing unit depending on the output value.

In addition, the fans can be equipped, e.g. with a Danfoss Saginomiya fan speed regulator, type RGE. This allows good condensing pressure control and reduces the noise level. The fans are provided with self-lubricating bearings, which ensures many years of maintenance-free operation.

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If the motor does not work, you can determine by means of resistance measurement whether the cause is a switched oﬀ winding protection switch or a possible broken winding.

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Stop valves Danfoss condensing units are provided with stop

valves on the suction and liquid side.

The stop valves of the condensing units with the 1-cylinder compressors (types TL, FR, NL, SC and SC TWIN) are closed by turning the

spindle clockwise to the soldered piece. This opens the ﬂow between the pressure gauge connection and the ﬂare connection. If you turn the spindle counter-clockwise to the rear stop, the pressure gauge connection is closed. The ﬂow between the soldered and the ﬂare connection is free. In the centre position, the ﬂow through the three connections is free. The accompanying soldered adapters help prevent ﬂare connections and to make the system hermetic.

The stop valves of the condensing units with Maneurop® reciprocating piston compressors MTZ and NTZ are directly ﬁtted into the suction

and discharge rotalock ports of the compressor and on the receiver. The suction valve is provided with long, straight tube pieces in such a manner that soldered connections can be carried out without disassembling the Rotalock valve.

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Fitters notes Danfoss compressors - Condensing units in general

Stop

Diﬀ.

Start

Diﬀ.

Stop

A B

Receiver

Pressure container ordinance

Liquid receiver is standard on Danfoss condensing units for use with expansion valves.

The expansion valve is regulating the level in the receiver buﬀer (the de- or increasing ﬂow of the refrigerant). The receivers from an internal volume of 3 l onwards are equipped with a Rotolock Valve.

Terminal box The Danfoss condensing units are electrically pre-

wired and equipped with a terminal box. Thus the power supply and additional electrical wiring can be easily ﬁtted. The terminal box of the condensing units with Maneurop® compressors is equipped with screw type connector blocks for both power

Safety pressure monitors Danfoss condensing units can be ordered

with safety pressure switches KP 17 (W, B…). Condensing units that do not come equipped with pressure switches from the factory must be equipped with a pressure switch at least the high-pressure side in systems with thermostatic expansion valves as per EN 378.

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and controls. The electrical connections of each component (compressor, fan(s), PTC, pressure switch) are centralised into this box. A wiring diagram is available in the cover of the electrical box. These terminal boxes are protected to a degree of IP 54.

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The following settings are recommended:

Refrigerant Low pressure side High pressure side

Cut in (bar) Cut oﬀ (bar) Cut in (bar) Cut oﬀ (bar) R407 2 1 21 25 R404A/R507 MBP 1.2 0.5 24 28 R404A/R507 LBP 1 0.1 24 28 R134a 1.2 0.4 14 18

Setup Danfoss condensing units must be set up in a

well ventilated location. You must ensure that there is suﬃcient fresh air

for the condenser at the intake end. In addition, you must ensure that no cross-ﬂow

The ventilator motor is connected in such a way that the air is drawn in via the condenser in the direction of the compressor.

For optimal operation of the condensing unit, the condenser must be cleaned regularly.

occurs between the fresh air and the exhaust air.

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compressors

Danfoss

Fitters notes Danfoss compressors - Condensing units in general

Evaporator

Condenser

Compressor

Protective weatherresistant housing

Careful installation

Contamination and foreign particles

Danfoss condensing units that are set up outside must be provided with a protective roof or with protective weather-resistant housing. The scope of delivery includes optional, high-quality protective weather-resistant housings. You can ﬁnd the order numbers in the current price list or you can contact your nearest Danfoss representative

More and more commercial cooling and air-conditioning systems are installed with condensing units that are equipped with

Contamination and foreign particles are among the most frequent causes that negatively impact the reliability and lifespan of cooling systems. During the installation, the following types of contamination can enter the system:

Scaling during soldering (oxidations) Flux residue from soldering Humidity and outside gasses Shavings and copper residues from deburring

the tubing

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hermetic compressors. High demands are put on the quality of the installation work and the alignment of such a cooling system.

For this reason, Danfoss recommends the following precautions:

Use only clean and dry copper tubing and

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components that satisfy standard DIN 8964. Danfoss oﬀers a comprehensive and integral

range of products for the necessary cooling automation. Please contact your Danfoss dealer for additional information.

Doing the pipe work When laying the tubing, you should try to make

the shortest and most compact pipe work possible. Low-lying areas (oil traps), where oil might accumulate should be avoided.

Tubing layout of the condensing units with 1-cylinder compressors (types TL, FR, NL,SC and SC-TWIN)

1. Condensing unit and evaporator are located on the same level.

The suction line should be arranged slightly downward from the compressor. The max. permissible distance between the condensing unit and the cooling position (vaporizer) is 30 m.

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Suction Line Liquid Line

Diameter copper pipe [mm] TL 8 6 FR 10 6 NL 10 6 SC 10 8

SC-TWIN 16 10

Fitters notes Danfoss compressors - Condensing units in general

Tubing layout of the condensing units with 1-cylinder compressors (types TL, FR, NL,SC and SC-TWIN) (cont.)

To ensure the oil return, the following crosssections are recommended for the intake and liquid lines:

2. The condensing unit is arranged above the

evaporator.

The ideal height diﬀerence between the condensing unit and the evaporator position is a max. of 5 m. The tube length between the condensing unit and the evaporator should not exceed 30 m. The suction lines must be laid out with double arcs in the form of oil traps above and below. This is done using a U-shaped arc at the lower end and a P-shaped arc at the upper end of the vertical riser. The max. distance between the arcs is 1 to 1.5 m. To ensure the oil return, the

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following pipe diameters are recommended for the suction and liquid lines:

Suction Line Liquid Line

Diameter copper pipe [mm] TL 8 6 FR 10 6 NL 10 6 SC 12/15 10 8 All other SCs 12 8 SC TWIN 16 10

3. The condensing unit is arranged under the

evaporator.

The ideal height diﬀerence between the condensing unit and the evaporator is a max. of 5 m. The tube length between the condensing unit and the evaporator should not exceed 30 m. The suction lines must be laid out with double arcs in the form of oil traps above and below. This is done using a U-shaped arc at the lower end and a P-shaped arc at the upper end of the vertical riser. The max. distance between the arcs is 1 to 1.5 m. To ensure the oil return, the following pipe diameters are recommended for the suction

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and liquid lines:

Suction Line Liquid Line

Diameter copper pipe [mm] TL 8 6 FR 10 6 NL 10 6 SC 12 8 SC TWIN 16 10

compressors

Danfoss

Fitters notes Danfoss compressors - Condensing units in general

Evaporator

Compressor

As short as possible

To condenser

0.5 fall, 4 m/s or more

To condenser

U shaped arc

U shaped arc as short as possible

8 to 12 m/s

Evaporator

0.5 fall, 4 m/s or more

U shaped arc as short as possible

max. 4 m

To compressor

8 to 12 m/s at lowest capacity

From evaporator

8 to 12 m/s at highest capacity

U shaped arc as short as possible

Tubing layout of the condensing units with hermetic Maneurop® reciprocating piston compressors, 1 -2-4 cylinder

The tubes should be laid out to be ﬂexible (dispersible in three planes or with “AnaConda”). When laying the tubing, you should try to make the shortest and most compact tubing network possible.

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Low-lying areas (oil traps), where oil might accumulate should be avoided. Horizontal lines should be laid inclined slightly downward toward the compressor. To guarantee the oil return, the suction speed at the risers must be at least 8-12 m/s.

For horizontal lines, the suction speed must not fall below 4 m/s. The vertical suction lines must be laid out with double arcs in the form of oil traps above and below. This is done using a U-shaped arc at the lower end and a P-shaped arc at the upper end of the vertical tubing. The maximum height of the riser is 4 m, unless a second U-shaped arc is attached.

If the evaporator is mounted above the condensing unit, you must ensure that no liquid refrigerant enters the compressor during the work-stoppage phase. To avoid condensation droplets from forming and to prevent an unwanted rise of the intake gas over-heating, the suction line must generally be insulated. Adjusting the intake gas over-heating is done individually for each use. You can ﬁnd more detailed information in the following sections under “max. permitted temperatures.“

Leak check Danfoss condensing units are checked in the

factory for leaks using helium. They are also ﬁlled with a protective gas and must therefore be evacuated from the system. In addition, the added refrigerant circuit must be leak-checked using nitrogen. The suction and liquid valves of the condensing unit remain closed during this. The use of coloured leak-checking agents will void the warranty.

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Fitters notes Danfoss compressors - Condensing units in general

Danfoss

compressors

Soldering The most common solders are alloys of 15% silver

and with copper, zinc and tin, i.e. “silver solder“. The melting point is between approx. 655°C and 755°C. The coated silver solder contains the ﬂ ux needed for soldering. This should be removed after soldering.

Silver solder can be used to solder together various materials, e.g. steel/copper. Ag 15% solder is suﬃ cient to solder copper to copper.

Protective gas

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At the high soldering temperatures under the inﬂ uence of ambient air, oxidation products form (scaling).

The system must therefore have protective gas ﬂ owing through it when soldering. Supply a weak stream of a dry, inactive gas through the tubes.

Only begin soldering when there is no atmospheric air left in the aﬀ ected component. Initiate the work procedure with a strong stream of protective gas, which you can reduce to a minimum when you start soldering.

This weak ﬂ ow of protective gas must be maintained during the entire soldering process.

The soldering must be done using nitrogen and gas with a gentle ﬂ ame. Only add the solder when the melting point temperature has been reached.

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Fork burner:

Fitters notes Danfoss compressors - Condensing units in general

Evacuating and ﬁlling

The vacuum pump should be able to suction oﬀ the system pressure to approx. 0.67 mbar, in two stages if possible.

Humidity, ambient air and protective gas should be removed. If possible, provide for a two-ended evacuation, from the suction and the liquid side of the condensing unit.

Use the connections at the suction and discharge valves of the condensing units.

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For ﬁlling the system, a ﬁlling level indicator, ﬁlling cylinder and/or a scale is used for smaller condensing units. The refrigerant can be fed into the liquid line in the form of a liquid if a ﬁlling valve is installed.

Otherwise, the refrigerant must be fed into the system in gaseous form via the suction stop valve while the compressor is running (break the vacuum beforehand).

Please observe that the refrigerants R404A, R507 and R407C are mixtures.

The refrigerant manufacturers recommend ﬁlling R507 as a liquid or gas, whereas R404A and especially R407C should be ﬁlled in liquid form. Therefore we must recommend that R404A, R507 and R407C are ﬁlled as described using a ﬁlling valve.

If the amount of refrigerant to be ﬁlled is unknown, continue ﬁlling until no bubbles are visible in the inspection glass. During this, you need to keep a constant watch on the condensing and suction gas temperature in order to guarantee normal operating temperatures.

Please observe the following procedures for evacuating and ﬁlling the Danfoss condensing units with the 1-cylinder compressors, types

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TL, FR, NL, SC and SC TWIN.

For evacuating, both external hoses are connected to a service battery aid and the condensing unit is evacuated with stop-valves 1 and 2 open (spindle in the center position).

After evacuation, both valves (4 and 5) are connected to the service battery. Only then is the vacuum pump switched oﬀ.

The refrigerant bottle is connected at the centre connection of the service battery aid 3, and the ﬁlling piece is brieﬂy vented.

The corresponding valve of service battery aid 4 is opened and the system is ﬁlled via the manometer connection of the suction stop valve with the maximum allowable refrigerant operating ﬁlling for a compressor that is in operation.

Fitters notes Danfoss compressors - Condensing units in general

Time (minutes)

Pressure (10

-3

mm QS)

Evacuating and ﬁlling (cont.) Please observe the following recommendation

for evacuating and ﬁlling the Danfoss condensing units with condensing units with hermetic Maneurop® reciprocating piston compressors MTZ and NTZ.

We recommend that you carry out the evacuation as described in the following:

1. The service valves of the condensing unit must be closed.

2. After the leak check, if possible, a two-ended evacuation should be carried out using a vacuum pump to 0.67 mbar (abs.)

It is recommended that you use coupling lines with a large through-put and that you connect them to the service valves.

3. Once a vacuum of 0.67 is reached, the system is separated from the vacuum pump. During the next 30 minutes, the system must not rise. If the pressure rises quickly, the system has a leak.

A new leak check and evacuation (after 1) must be carried out. If the pressure rises slowly, this is an indication that humidity is present. If this is the case, perform a new evacuation (after 3).

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Exceeding the max. allowable operational ﬁlling capacity and setting up outdoors

4. Open the service valves of the condensing unit and break the vacuum with nitrogen. Repeat procedures 2 and 3.

General information:

The compressor should only be switched on if the vacuum has been broken.

For compressor operation with a vacuum in the compressor housing, there is a risk of voltage spark-over in the motor winding.

If the refrigerant is ﬁlled beyond the max. allowable operational ﬁlling capacity or when setting up outdoors, protective precautions must be taken.

You can ﬁnd the max. allowable operational ﬁlling capacities in the technical information and/or installation instructions for the Danfoss compressors. If there are any questions, your local Danfoss sales company will be glad to assist you.

One quick and easy solution for preventing refrigerant displacements during the shut-down phases is the use of a crank case heater.

compressors

Danfoss

Fitters notes Danfoss compressors - Condensing units in general

Exceeding the max. allowable operational ﬁlling capacity and setting up outdoors (cont.)

For Danfoss condensing units that are equipped with 1-cylinder compressors, types TL, FR, NL,SC and SC TWIN, following size of

crank case heaters can be used:

Crank case heater for TL/FR/NL 35 W, order no. 192H2096

Crank case heater for SC and SC-TWIN 55 W, order no. 192H2095

Housing heaters must be mounted directly above the welded seam. For TWIN compressors, both compressors must have a housing heater. The electrical connection can be carried out as follows:

For activated main switches, the change-over contact of the regulating thermostat (e.g. KP 61) takes over the switching function, i.e. compressor oﬀ – heater on, and vice versa. The housing heater should also be switched on approx. 2-3 hours before startup after a long down-time of the cooling system. For setting up the condensing units outdoors, it is generally recommended to use housing heaters. Please observe the following wiring recommendations.

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The Danfoss condensing units with hermetic 1, 2 or 4-cylinder Maneurop® reciprocating piston compressors MTZ and NTZ come

standard equipped with a self-regulating PTC 35 W crank case heater.

The self-regulating PTC heater protects against refrigerant displacement during the shutdown phase. However, reliable protection is only aﬀorded when the oil temperature is 10 K above the saturation temperature of the refrigerant.

It is advisable to check by means of tests that a suﬃcient oil temperature is reached for both low and high ambient temperatures.

For condensing units that are set up outdoors and exposed to low ambient temperatures or for cooling applications with larger amounts of

refrigerant, an additional belt crank case heater is often required for the compressor.

The heater should be mounted as close to the oil sump as possible in order to ensure eﬃcient transfer of heat to the oil. Belt crank case heaters are not self-regulating.

The regulating is supposed to be achieved by the heater being switched on when the compressor is stopped and switched oﬀ when the compressor is running.

These measures prevent the refrigerant from condensing in the compressor. You must observe that the crank case heater is switched on at least 12 hours prior to the compressor startup whenever the condensing units are being restarted after a long down-time.

Fitters notes Danfoss compressors - Condensing units in general

Thermostat

Solenoid valve

Expansion valve

Sight glass

Filter drier

Evaporator

“Pump-down switching“ If it is not possible to keep the oil temperature

at 10 K over the saturation temperature of the refrigerant using the crank case heater during compressor down-time or when liquid refrigerant ﬂows back, a pump-down switching process on the low pressure end must be used to prevent the further possibility of refrigerant displacement during shutdown phases.

The solenoid valve in the liquid line is controlled by a thermostat. If the solenoid valve closes, the compressor provides suction on the low pressure end until the low pressure switch switches oﬀ the compressor at the set switching point.

With “pump-down switching,“ the activation point of the low pressure switch must be set lower than the saturation pressure of the refrigerant at the lowest ambient temperature of the condensing unit and the evaporator.

A liquid separator provides protection against refrigerant displacement at the start-up, during operation or after the hot gas defrosting process.

The liquid separator protects against refrigerant displacement during the shut-down period while the internal free volume of the suction end of the system is increased.

The liquid separator should be laid out according to the manufacturer’s recommendations.

As a rule, Danfoss recommends that the holding capacity of the liquid separator not be less than 50% of the entire system’s ﬁlling capacity.

A liquid separator should not be used in systems with zeotropic refrigerants such as R407C, for example.

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compressors

Danfoss

Fitters notes Danfoss compressors - Condensing units in general

Max. allowable temperatures For the Danfoss condensing units with 1-

cylinder compressors (types TL, FR, NL,SC and SC TWIN), the evaporator superheat (measured

at the sensor of the expansion valve meaning the temperature at pressure gauge) should be between 5 and 12 K.

The max. return gas temperature is measured at the compressor intake: 45°C. Impermissibly high intake gas over-heating leads inevitably to a quick rise in the discharge temperature.

This must not exceed 135°C for the SC compressor and 130°C for the TL, NL and FR compressors.

The pressure tube temperature is measured 50 mm away from the pressure connector of the compressor.

For condensing units with hermetic Maneurop® reciprocating piston compressors MTZ and NTZ, the evaporator superheat (E-valve

sensor) should be between 5 and 12 K. The max. return gas temperature, measured at

the compressor suction connector is 30°C. Impermissibly high intake gas superheat

inevitably leads to a rapid rise in the pressure gas temperature, the maximum value of which must not be exceeded (130°C).

For special applications (multi-evaporator systems), the use of an oil separator is recommended in the pressure line.

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Fitters notes Danfoss compressors - Repair of hermetic refrigeration systems

Contents Page

1.0 General .............................................................................................................................................................................. 97

1.1 Fault location ............................................................................................................................................................ 97

1.2 Replacement of thermostat ................................................................................................................................. 98

1.3 Replacement of electrical equipment ..............................................................................................................99

1.4 Replacement of compressor ............................................................................................................................... 99

1.5 Replacement of refrigerant ................................................................................................................................. 99

2.0 Rules for repair work ...................................................................................................................................................101

2.1 Opening of the system .........................................................................................................................................101

2.2 Brazing under an inertprotective gas .............................................................................................................102

2.3 Filter drier .................................................................................................................................................................102

2.4 Moisture penetration duringrepair ................................................................................................................. 103

2.5 Preparation of compressorand electrical equipment ..............................................................................103

2.6 Soldering ..................................................................................................................................................................104

2.7 Evacuation ................................................................................................................................................................105

2.8 Vacuum pump and vacuum gauge ................................................................................................................ 105

3.0 Handling of refrigerants .............................................................................................................................................106

3.1 Charging with refrigerant .................................................................................................................................... 106

3.2 Maximum refrigerant charge ............................................................................................................................106

3.3 Test .............................................................................................................................................................................. 107

3.4 Leak test .....................................................................................................................................................................107

4.0 Replacement of defective compressor .................................................................................................................108

4.1 Preparation of components .............................................................................................................................108

4.2 Removal of charge ................................................................................................................................................ 108

4.3 Removal of defective compressor ...................................................................................................................108

4.4 Removal of refrigerantresidues ........................................................................................................................108

4.5 Removal of ﬁlter drier ..........................................................................................................................................108

4.6 Cleaning of solder joints andreassembly .....................................................................................................108

5.0 From R12 to other refrigerants ................................................................................................................................109

5.1 rom R12 to alternativerefrigerant ....................................................................................................................109

5.2 From R12 to R134a .................................................................................................................................................109

5.3 From R134a to R12 ................................................................................................................................................109

5.4 From R502 to R404A .............................................................................................................................................109

6.0 Systems contaminated with moisture ..................................................................................................................110

6.1 Low degree ofcontamination ........................................................................................................................... 110

6.2 High degree ofcontamination ...........................................................................................................................110

6.3 Drying of compressor ...........................................................................................................................................111

6.4 Oil charge .................................................................................................................................................................. 111

7.0 Lost refrigerant charge ...............................................................................................................................................112

8.0 Burnt compressor motor ...........................................................................................................................................113

8.1 Oil acidity .................................................................................................................................................................113

8.2 Burnt system ...........................................................................................................................................................113

compressors

Danfoss

Notes

Fitters notes Danfoss compressors - Repair of hermetic refrigeration systems

1.0 General

Repairs of refrigerators and freezers demand skilled technicians who are to perform this service on a variety of diﬀerent refrigerator types. Previously service and repair were not as heavily regulated as now due to the new refrigerants, some of which are ﬂammable.

Fig. 1: Hermetic refrigeration system with capillary tubes

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Fig. 1 shows a hermetic refrigeration system with capillary tube as expansion device. This system type is used in most household refrigerators and in small commercial refrigerators, ice cream freezers and bottle coolers. Fig. 2. shows a refrigeration system using a thermostatic expansion valve. This system type is mainly used in commercial refrigeration systems.

Fig. 2: Hermetic refrigeration system with expansion valve

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Repair and service is more diﬃcult than new assembly, since working conditions “in the ﬁeld” are normally worse than in a production site or in a workshop. A precondition for satisfactory service work is that the technicians have the right qualiﬁcations, i.e. good workmanship, thorough knowledge of the product, precision and intuition. The purpose of this guide is to increase the knowledge of repair work by going through the basic rules. The subject matter is primarily dealt with reference to repair of refrigeration systems for household refrigerators “in the ﬁeld“ but many of the procedures may also be transferred to commercial hermetic refrigeration installations.

1.1 Fault location

Before performing any operations on a refrigeration system the progress of the repair should be planned, i.e. all necessary replacement components and all resources must be available. To be able to make this planning the fault in the system must ﬁrst be known. For fault location tools must be available as shown in ﬁg. 3. Suction and discharge manometer, service valves, multimeter (voltage, current and resistance) and a leak tester. In many cases it can be concluded from the user’s

Fig. 3: Pressure gauges, service valve, multimeter and leak tester

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Main switch released

One potential fault may be a defective fuse, and the reason may be a fault in the motor windings or in the motor protector, a short circuit or a burnt current lead-in on the compressor. These faults require the compressor to be replaced.

Compressor

Starting device and compressor motor may be a wrong choice. Compressor motor or winding protector may be defective, and the compressor

statements which faults could be possible, and for most faults a relatively accurate diagnosis can be made. However, a precondition is that the service technician has the necessary knowledge of the functioning of the product and that the right resources are available. An elaborate fault location procedure will not be gone through here, however, the most common faults where the compressor does not start or run are mentioned in the following.

Frequent reasons for reduced refrigeration capacity are coking or copper platings due to moisture or non-condensable gases in the system.

Blown gaskets or broken valve plates are due to too high peak pressures and short-time pressure peaks as a result of liquid hammering in the compressor, which may be due to a too high refrigerant charge in the system or a blocked capillary tube.

may be mechanically blocked.

compressors

Danfoss

Fitters notes Danfoss compressors - Repair of hermetic refrigeration systems

1.1 Fault location (cont.)

The voltage may be too low or the pressure too high for the compressor. Non equalized pressure causes the motor protector to cut out after each start and will eventually result in a burnt motor winding. A defective fan will also aﬀect the compressor load and may cause motor protector cut outs or blown gaskets.

In case of unsuccessful start and cold compressor up to 15 minutes may pass until the winding protector cuts the compressor out. If the winding protector cuts out when the compressor is hot up to 45 minutes may pass until the protector cuts the compressor in again. Before starting a systematic fault location it is a good rule to cut oﬀ the voltage to the compressor for 5 minutes. This ensures the PTC starting device, if any, to be cooled suﬃciently to be able to start the compressor.

Should a brief power failure occur within the ﬁrst minutes of a refrigeration process, a conﬂict situation (interlocking) may arise between the protector and the PTC. A compressor with a PTC starting device cannot start in a system that is not pressure-equalized, and the PTC cannot cool so quickly. In some cases it will take up to 1 hour until the refrigerator runs normally again.

High and low pressure switches

Cut out of the high pressure switch may be due to too high condensing pressure, probably caused by lack of fan cooling. A cut-out low pressure switch may be due to insuﬃcient refrigerant charge, leakage, evaporator frost formation or partial blockage of the expansion device.

The cut out may also be due to a mechanical failure, wrong diﬀerence setting, wrong cut-out pressure setting or irregularities in pressure.

Thermostat

A defective or incorrectly set thermostat may have cut out the compressor. If the thermostat loses sensor charge or if the temperature setting is too high, the compressor will not start. The fault may also be caused by a wrong electrical connection. Too low a diﬀerential (diﬀerence between cut in and cut out temperature) will cause too short compressor standstill periods, and in connection with a LST compressor (low starting torque) this might lead to starting problems. See also point 1.2 “ Replacement of thermostat”.

For further details please refer to “Fault location and prevention in refrigeration circuits with hermetic compressors”.

A careful fault determination is necessary before opening the system, and especially before removing the compressor from the system. Repairs requiring operations in a refrigeration system are rather costly. Before opening old refrigeration systems it may therefore be appropriate to make sure that the compressor is not close to breaking down though it is still functional. An estimation can be made by checking the compressor oil charge. A little oil is drained in to a clean test glass and is compared with a new oil sample. If the drained oil is dark, opaque and containing impurities, the compressor should be replaced.

1.2 Replacement of thermostat

Before replacing the compressor it is a good idea to check the thermostat.

A simple test can be made by short-circuiting the thermostat so the compressor gets power directly. If the compressor can operate like this the thermostat must be replaced.

For replacement it is essential to ﬁnd a suitable type, which may be diﬃcult with so many thermostat types in the market. To make this choice as easy as possible several manufacturers, i.e. Danfoss, have designed so-called “service thermostats” supplied in packages with all accessories necessary for thermostat service. With eight packages, each covering one type of

Fig. 4: Service thermostat package

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refrigerator and application, service can be made on almost all common refrigerators. See ﬁg. 4. The application area of each thermostat covers a wide range of thermostat types. Moreover, the thermostats have a temperature diﬀerential between cut in and cut out suﬃcient to ensure satisfactory pressure equalization in the system standstill periods.

In order to achieve the requested function the thermostat sensor (the last 100 mm of the capillary tube) must always be in close contact with the evaporator.

When replacing a thermostat it is important to check whether the compressor operates satisfactorily both in warm and cold position, and whether the standstill period is suﬃcient for the system pressure equalization when using a LST compressor.

With most thermostats it is possible to obtain a higher temperature diﬀerential by adjusting the diﬀerential screw. Before doing this it is recommended to seek advice in the thermostat data sheet which way the screw must be turned. Another way of obtaining a higher diﬀerential is to place a piece of plastic between the sensor and the evaporator, since 1 mm plastic results in approx. 1°C higher diﬀerential.

Danfoss Hints and tips for the installer Service guide

Specifications and Main Features

Frequently Asked Questions

User Manual

Introduction

Superheat

Subcooling Subcooling is deﬁ ned as the diﬀ erence between

External pressure equalization

Charges Thermostatic expansion valves can contain one

Universal charge

MOP charge

MOP ballast charge

Thermostatic expansion valve selection

Installation The expansion valve must be installed in the

Setting The expansion valve is supplied with a factory

Installation

Setting

Low-pressure control

High-pressure control

Setting LP for outdoor location

Test of contact function

The correct pressure control for your system

Installation

Setting

Setting example

Test of contact function

KP 98 dual thermostat

Vapour charge

Absorption charge

Low voltage

Application

KVC capacity regulator

Installation

Pressure testing

Evacuation

Fitters notes Pressure regulators

Setting

Danfoss pressure regulators

Application

Installation

Setting

Maintenance

Spare parts

Function

Filter drier selection

Installation

Soldering

Operation

Using gaskets

Mounting gaskets

Disposal

Filter drier replacement

Combidriers type DCC and DMC

Special application

Dimensioning

EPD (Equilibrium Point Dryness)

Drying capacity (water capacity)

Liquid capacity (ARI 710*)

Recommended system capacity

Filter driers from Danfoss