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

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

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

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

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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

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Notes

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Fitters notes	Thermostatic expansion valves
Introduction	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.

Ad0-0001

Superheat	Superheat is measured at the point where the
	bulb is located on the suction line and is the
	difference 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.

Ad0-0012

Subcooling	Subcooling is defined as the difference 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.

Ad0-0015

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Fitters notes	Thermostatic expansion valves
External pressure		Expansion valves with external pressure equali-
equalization		zation 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 equali-
		zation 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.	Ad0-0016
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.
		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.

MOP charge	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.

Ad0-0017

Ad0-0018

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.

MOP is often called “Motor Overload Protection”.

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Fitters notes	Thermostatic expansion valves

MOP ballast charge	Expansion valves with MOP ballast charges are
	used mainly in refrigeration systems with “high-
	dynamic” 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.

Ad0-0021

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.

Thermostatic expansion	The thermostatic expansion valve can be selec-
valve selection	ted when the following are known:
		Refrigerant		Subcooling
		Evaporator capacity		Pressure drop across valve
		Evaporating pressure		Internal or external pressure equalization
		Condensing pressure

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.
				Ad0-0019
	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.			Ad0-0023

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.

Ad0-0020

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Fitters notes

Thermostatic expansion valves

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 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.

The bulb must be able to sense the temperature 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 fitting 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 fitter 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.

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

Ad0-0002

Ad0-0003

Ad0-0004

Ad0-0005

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

Ad0-0006

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Fitters notes	Thermostatic expansion valves

Installation (cont.)	As previously mentioned, the bulb must be	<![if ! IE]> <![endif]>valvesexpansion	<![if ! IE]> <![endif]>Thermostatic
	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.
		Ad0-0007

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

Ad0-0008

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.

Ad0-0009

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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.

Ad0-0010

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.	Ad0-0011

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.

		Ad0-0013
Orifice assembly	If the evaporator continues to hunt, regardless of
replacement	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.
		Ad0-0014
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Fitters notes	Thermostatic expansion valves
Danfoss product range	Danfoss offers a comprehensive range of
Thermostatic expansion	thermostatic expansion valves with capacities
valves	from 0.4 to 1083 kW (R134a).
	T/TE 2 valves have a brass housing and flare/		TDE valves have a brass housing and copper
	flare or solder/flare connections.		solder connections.
	Rated capacity: 0.4 - 10.5 kW (R134a).		Rated capacity: 10.5 - 140 kW (R407C)
	TUA, TUB, TUC valves have a stainless steel		The valves are supplied with a fixed orifice and
			adjustable superheat.
	housing and stainless steel/copper bimetal
	solder connections.		TE 5 - TE 55 valves have a brass housing.
	Rated capacity: 0.5 - 12 kW (R134a).
			The valves are supplied as a part programme
	The valves can be supplied with or without		consisting of valve housing, orifice and thermo-
	external pressure equalization.		static element.
		TUA has an interchangeable orifice	The valve housing is available in a straightway
		assembly and adjustable superheat.	or angleway version with solder, flare and flange
		TUB has a fixed orifice and adjustable	connections.
		superheat.	Rated capacity: 12.9 - 220 kW (R134a).
		TUC has a fixed orifice and factory set
			The valves are supplied with external pressure
		superheat.
			equalization.
	TUB and TUC are primarily for OEM customers.
	All TUB and TUC valves can be replaced by TUA
	valves.		PHT 85 - 300 valves are supplied as a part
			programme consisting of valve housing, flanges,
	TCAE, TCBE, TCCE valves have a stainless steel		orifice and thermostatic element.
			Rated capacity: 55 - 1083 kW (R134a).
	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.

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.

For further information consult the internet or the catalogue material.

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Fitters notes	Solenoid valves

Contents						Page
Installation . . . . . . . . .	. . . . . . . . . . . . . . . . . . . .	. . . . . . . . . .		. . .		.	. 15
EVRA 32 & 40 precautions	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . .	.	. . . . .	.	. .	. 15
When pressure testing . .	. . . . . . . . . . . . . . . . . . . .	. . . . . . . . .	.	. .	.	.	16
The coil . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . .	. . . . . . . . .	.	. .	.	.	17
The correct product . . . . .	. . . . . . . . . . . . . . . . . . . .	. . . . . . . . .	.	. .	.	.	18
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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.
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	This avoids liquid hammer when the solenoid
	valve opens.
			Af0_0001
	Ensure that pipes around the valve are properly
	installed so that no fracture can occur.
			Af0_0003
	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.
EVRA 32 & 40 precautions	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).
		Af0_0004

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Fitters notes

Solenoid valves

When pressure testing	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 fitted).
	Remember to screw the spindle back before
	starting up, otherwise the valve will be unable to
	close.

Af0_0005

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

Af0_0006

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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		<![if ! IE]> <![endif]>Solenoid
and that the surface is free from paint or any
other material.
Note: The O-ring must be changed at service.		<![if ! IE]> <![endif]>valves
	Af0_0018
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.
	Af0_0019

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.

Af0_0009

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).

Af0_0010

Be aware of the colour of leads in the cable.

Yellow/green is always earth.

Leads of one colour are either phase or neutral.

Af0_0011

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Fitters notes	Solenoid valves

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

Af0_0012

The correct product	Make sure that coil data (voltage and frequency)
(The “old” coil type)	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	Af0_0013
	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	Af0_0014
	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.
(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.
		Af0_0015

Af0_0020

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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
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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.

Al0_0001

	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 incor-
	porating 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
		Al0_0007
	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.

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

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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.

Al0_0009

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.

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

Al0_0010

Al0_0011

Setting	KP pressure controls can be preset using a com-
	pressed air cylinder. Ensure that the change-over
	contacts are correctly connected for the required
	function.
Low-pressure control	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.
High-pressure control	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.
		Al0_0012
	Remember: The scales are indicative only.

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Fitter notes	Pressure controls

Example with four compressors	Medium: ice cream at –25°C,
in parallel (R404A)	t0 ≈ –37°C,
	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.

Compressor	CUT OUT	CUT IN
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

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

Setting LP for outdoor location 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

Indicative evaporating pressures (pe) for different types of systems

Room temp. (tr)	System type	Difference		Evaporating	RH	Setting of KP2/KP1
		between te		pressure (pe)	[%]	(cut in - cut out)
		and tmedia (air)				D = Operating press. cont.
						S = Safety press. cont.
+0.5°/+2°C	Fan-cooled	10K		1.0 - 1.1 bar	85	0.9	- 2.1 bar (D)
	meat cold room			(R134a)
+0.5°/+2°C	Meat cold room with	12K		0.8 - 0.9 bar	85	0.7	- 2.1 bar (D)
	natural air circulation			(R134a)
–1°/0°C	Refrigeration meat	14K		0.6 bar	85	0.5	- 1.8 bar (D)
	counter (open)			(R134a)
+2°/+6°C	Milk cold room	14K		1.0 bar	85	0.7	- 2.1 bar (D)
				(R134a)
0°/+2°C	Fruit cold room	6K		1.3 - 1.5 bar	90	1.2	- 2.1 bar (D)
	Vegetable chiller			(R134a)
–24°C	Freezer	10K		1.6 bar	90	0.7	- 2.2 bar (S)
				(R404A)
–30°C	Ventilated deep	10K		1 bar	90	0.3	- 2.7 bar (S)
	freeze room			(R404A)
–26°C	Ice cream freezer	10K		1.4 bar	90	0.5	- 2.0 bar (S)
				(R404A)

Al0_0015

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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 high-
	pressure 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

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Fitter notes	Pressure controls
The correct pressure control	KP with solder connections can be used instead
for your system	of flare connections on hermetic systems.

Al0_0006

In ammonia plant where KP pressure controls are used, they must be type KP-A.

A connector with M10 × 0.75 – 1/4 - 18 NPT (code no. 060014166).

Al0_0002

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.

Al0_0003

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_0004

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Fitter notes	Pressure controls

The correct pressure control For systems where KP is activated occasionally for your system (cont.) (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

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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
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Notes

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