Danfoss Hints and tips for the installer Service guide

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

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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.

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Al0_0012

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

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

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

+ 182 hidden pages

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