Danfoss KPU Series Installation Manual page 2

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 dual pressure
switch on LP side is higher than the refrigeration line as
that will prevent liquid migration and accumulation in
the bellows.
Mount the KPU pressure switch on a bracket or on a completely
flat surface. Mounting to an uneven surface might cause
improper switch operation.
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.
2 | 520H11521 | DKRCC.PI.CD0.C6.02
Recommended
mounting position
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.
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 should not protrude into the
switch more than 1/8 in).
Screws for
bracket mounting
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.
8. Do not over tighten flare nuts as it may damage the threads
causing leaks.
9. Protect the capillary tube from damage caused by vibrations
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.
– when the switch is mounted remote from the compressor,
make the pressure connections away from the compressor.
– when the switch is mounted remote 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.
Mounting holes
for flat surfaces
© Danfoss | DCS (jmn) | 2017.01