Installation guide
Pressure switch
KPU
Application
KPU pressure switches are for use on commercial
refrigeration and air conditioning systems to give protection
060R9767
against excessively low suction pressure or excessively
high discharge pressure.
They are also used for starting and stopping refrigeration
Refrigerants:
R22, R134a, R404A, R407A, R407C, R407F, R410A*), R422B,
R422D, R438A, R448A, R449A, R450A, R452A, R507A, R513A
For complete list of approved refrigerants, go to
http://products.danfoss.com/all-products/
*) R410A only for KPU 6W and KPU 6B
compressors and fans on air-cooled condensers.
KPU pressure switches are fitted with the Single-Pole SingleThrow (SPST) or Single-Pole Double-Throw (SPDT) switches,
suitable for direct as well as indirect (with a contactor) control.
KPU pressure switches are available in several pressure ranges
and are compatible with refrigerants listed below. KPU 6W and
KPU 6B are fail safe switches for high pressure refrigerants.
Standard enclosure is ~NEMA 1.
Product Specification
Code number
Application Typ e
KPU 1 060-52 31 060- 5233 Auto. SPDT — 6 in. – 108 10 – 60 250 290
Low Pressure
Switch Cut O ut
on pressure
fall
Fan switch KPU 5 060 -5241 060-5242 Auto. SPST(NO) close High open Low 100 – 465 25 – 85 510 530
High Pressure
Switch
Cut Out on
pressure rise
* 610psig - MWP for products used according to 2014/68/EU PED directive.
KPU 1 060- 5236 — Auto. SPST(NO) close High open Low 6 in. – 108 10 – 60 250 290
KPU 2 060-5237 060 -5235 Auto. SPST(NO) close High open Low 6 in. – 73 6 – 30 250 290
KPU 2 060-5239 060 -5240 Auto. SPDT — 6 in. – 73 6 – 30 250 290
KPU1B 060 -5232 060-52 34 Man (Min.) SPDT — 28 in. – 100 10 fixed 250 290
KPU 6W
KPU
6B
¼ in
male flare
060 -5243 060-5245 Auto. SPDT — 100 – 600 58 – 145 675 / 610* 725
060 -5244 060-5246 Man. (Max.) SPDT — 100 – 600 60 fixed 675 / 610* 725
36 in. cap.
tube w. ¼
in flare nut
Reset
Contact system
Typ e
Switch
action
Regulating
range
[inHg] [psig]
Differential
∆p
[psi]
Max.
working
pressure
[psig]
Max.
testing
pressure
[psig]
060R9767
Ambient
temp.
[°F]
-40 – 122
(175 for
max.
2 hours)
Installation
Select an accessible location, where the switch and pressure connection line will not be subject to damage.
IMPORTANT:
Mount the pressure switch in a position that
will allow drainage of liquids away from switch
bellows. Pressure connection of the switch
must always be located on the top side of the
refrigerant line.
This reduces the possibility of oil, liquids, or
sediment collecting in the bellows, which could
cause the switch malfunction.
IMPORTANT:
Ensure the ambient temperature for the pressure
switch is higher than the refrigeration line as that
will prevent liquid migration and accumulation in
the bellows.
© Danfoss | DCS (sb) | 2019.12
AN212086434305en-000101 | 520H11543 | 1
Mount the KPU pressure switch on a bracket
or on a completely flat surface.
Mounting to an uneven surface might cause improper switch
operation.
For bracket mounting use only the 10-32x3/16 screws provided
with the switch. If other screws are used function of the
pressure switch might be disturbed (they may not protrude
into the switch more than 1/8 in.).
Use only the mounting holes provided; no other holes are to
be added to the switch.
IMPORTANT:
Pressure pulsations in the refrigeration system
reduce life time of the bellows and might disturb
switch function. Pressure pulsations should always be
effectively damped e.g. by connection the pressure
switches to the refrigeration system through a capillary
tube.
Recommendations for capillary tube and flare connections:
1. Ensure self-draining of the capillary tube to minimize
clogging.
2. Coil excess capillary tube into smooth, circular coils (approx.
3 inch diameter). The coiled tube should be securely fastened
in order to prevent possible damage due to vibration.
3. Leave a little slack in the capillary tube as it helps to damp
mechanical vibrations.
4. Avoid sharp bends as well as re-bending of the capillary tube
on the same point as it weakens the material, increasing the
risk of crack.
5. Never allow for contact between the capillary tube and sharp
or abrasive objects as during vibrations the tube could be
damaged due to friction.
6. Purge the piping before connecting pressure switches.
7. Always use two wrenches
tightening the flare nut on
the pressure switch. One
wrench should support the
connector while the second
wrench is used to tighten the
nut.
8. Do not over tighten flare nuts as it may damage the threads
9. Protect the capillary tube from damage caused by vibrations
–
– when the switch is mounted remote from the compressor,
– when the switch is mounted remote from the compressor
Screws for
bracket mounting
Mounting holes
for flat surfaces
causing leaks.
from compressor:
when the switch unit is mounted directly on the compressor,
the capillary must be secured to the compressor so that
everything vibrates as a whole.
make the pressure connections away from the compressor.
and the pressure connections have to be on the compressor,
then damping coils must be used between the compressor
and the pressure switch.
NOTE:
After installing the pressure switch, evacuate the plant in
accordance with applicable EPA and other regulations,
to remove air, moisture, and other contaminants.
Wiring
Electrical ratings according to UL regulations
120 V AC 24 FLA, 144 LRA – make only
240 V AC 24 FLA, 144 LRA – make only
240 V DC 12 W pilot duty
European electrical ratings according to EN 60947
AC1 AC3 AC15 LR DC13
16 A 16 A 10 A 112 A 12 W
400 V 220 V
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CAUTION:
Disconnect power supply before wiring connections
are made or service to avoid possible electrical shock or
damage to equipment.
Do never touch live parts with your fingers or with
any tool.
NOTE:
All wiring should conform to the National Electrical Code
and local regulations.
Use copper wire only.
Use terminal screws furnished in the contact block.
Do not exceed tightening torque 20 lb. in (2.3 Nm).
Do not exceed electrical ratings for the switch.
The terminal block as well as grounding screw
are accessible after dismounting of the front cover.
© Danfoss | DCS (sb) | 2019.12
Wiring Option A:
– Low Pressure Switch Cut Out on pressure fall
– Condenser Fan Cycling
Wiring Option B:
– High Pressure Switch Cut Out on pressure rise
Load ~Line
Wire dimensions: 10 AWG max.
Cable entry: 7/8 in. cable entry for ½ in. male pipe thread
connection (conduit boss) or similar (Pg13.5 or Pg16) screwed
cable entry.
Contact function test (Manual trip)
When the electrical leads are connected the contact function
can be manually tested regardless of pressure condition in
the system. The manual trip lever is located in the left side
of the KPU. It must be operated with fingers only. Do not use
screwdriver as it will damage the switch.
B
A
C
D
Load ~Line
Adjustment
Before adjustment, loosen the locking plate.
For setting use the Universal Refrigeration Wrench.
A
B
C
D
A: Manual trip. Press the lever up. USE FINGERS ONLY!
B: Manual reset button
(available only for contols with manual reset function)
C: Terminal block
D: Grounding screw
NOTE:
While operating the manual trip on KPU
switches with manual reset it is necessary
to push the reset knob.
© Danfoss | DCS (sb) | 2019.12
A: Differential adjusting screw
B: Locking plate
C: Range adjusting screw
D: Cover screw
NOTE:
Adjust the pressure switch with settings specified by the
manufacturer of the controlled quipment.
Do not exceed the pressure ratings of the controlled
equipment or any of its components when checking
pressure switch operation or operating the controlled
equipment.
Do not adjust pointers beyond the highest or lowest
indicator marks on the scale plate, as this may cause
inaccurate switch operation.
AN212086434305en-000101 | 520H11543 | 3
IMPORTANT:
The scale plate is only for reference and for more
precise setting a pressure gauge should be used.
IMPORTANT:
After installing and adjusting pressure switch run the
controlled equipment several times (at least three
cycles) at normal operating conditions.
Adjustment:
Low Pressure Switch
Cut out on pressure fall
with automatic reset.
Scale plate directly indicates
the Cut In and the Differential
set points.
Adjustment:
Low Pressure Switch
Cut out on pressure fall
with manual reset.
Scale plate directly indicates the Cut
Out set point. There is no pointer for
the Differential.
The Differential pressure value is
fixed and printed on the scale plate.
Adjustment:
Condenser Fan Cycling
Scale plate directly indicates
the Cut In and the Differential
set points.
1 2
1
1
1. Set Cut In by adjusting range screw.
Turn the screw clockwise to lower the set point.
2. Then set Differential by adjusting differential screw. Turn the
screw clockwise to increase the Differential.
3. The Cut Out setting equals the Cut In
less the Differential: CUT OUT = CUT IN - DIFFERENTIAL
NOTE:
Cut Out set point must be above absolute vacuum!
If the Differential is set too high then the switch
will not stop the compressor.
1. Set Cut Out by adjusting range screw.
Turn the screw clockwise to lower the set point.
2. The Cut In setting equals the Cut Out plus
the Differential: CUT IN = CUT OUT + 10 psi
2
1. Set Cut In by adjusting range screw.
Turn the screw clockwise to lower the set point.
2. Then set Differential by adjusting differential screw. Turn the
screw clockwise to increase the Differential.
3.The Cut Out setting equals the Cut In less
the Differential: CUT OUT = CUT IN - DIFFERENTIAL
Adjustment:
High Pressure Switch
Cut Out on pressure
rise with automatic reset.
Scale plate directly indicates
the Cut Out and the Differential
set points.
Adjustment:
High Pressure Switch
Cut Out on pressure
rise with manual reset.
Scale plate directly indicates
the Cut Out set point.
There is no pointer for the
Differential.
The Differential pressure value is
fixed and printed on the scale plate.
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1 2
1
1. Set Cut Out by adjusting range screw.
Turn the screw clockwise to lower the set point.
2. Then set Differential by adjusting differential screw. Turn the
screw clockwise to decrease the Differential.
3. The Cut In setting equals the Cut Out
less the Differential: CUT IN = CUT OUT - DIFFERENTIAL
1. Set Cut Out by adjusting range screw.
Turn the screw clockwise to lower the set point.
2. The Cut In setting equals the Cut Out
less the Differential: CUT IN = CUT OUT - 60 psi
© Danfoss | DCS (sb) | 2019.12
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