O-UC12-FEB23-3
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•
Listen for any possible leaks and check all joints with
bubble spray. If any leaks are discovered, release
pressure slowly from system until empty, repair leak and
then restart pressure testing procedure. Never attempt to
repair a leak on a pressurized system.
A strength test should also be incorporated according to local
regulations.
Once testing has been completed satisfactorily, release the
pressure from the system gradually and safely to external
atmosphere.
Evacuation and Charging
Moisture prevents proper functioning of the
compressor and the refrigeration system.
Ensure that a good quality vacuum pump is
used to pull a minimum vacuum of 250
microns (0.25 torr).
Once pressure testing has been completed, the system can
now be evacuated to remove air and any moisture from the
piping. This can be done as follows:
•
Ensure any nitrogen charge is safely released from the
system.
•
Connect a gauge manifold to the schrader connection of
the unit.
•
Connect a vacuum pump and vacuum gauge to the
system.
•
Evacuate the system until vacuum is below 250 microns
(0.25 torr).
Note: A triple evacuation procedure is recommended for all
new systems or where moisture is suspected.
Once the system is isolated and the vacuum pump is switched
off, any rise in pressure indicates that either there may be a
leak in the system or moisture is still present. In this case,
recheck the system for leaks, repair as necessary, and then
restart the evacuation procedure. Once completed
satisfactorily, the vacuum pump and vacuum gauge can be
removed.
Drainage
The evaporator drain pan fitting is supplied
loose and must be fitted on site.
Correct fitting is vital to ensure leak
–
free operation. The
lock nut on the drain fitting
MUST
be fitted the right way
around; otherwise, it will not tighten against the drip tray.
One side of the nut has an angled recess
–
this must be facing
towards the drip tray. The fitting does not require any
sealant, but a small amount of silicon sealant can be applied
between the flared face of the fitting and the drip tray if so
desired.
The fitting
is tied to the indoor unit’s fan guard and consists of:
•
1pcs aluminum alloy drain fitting
3/4” BSP male thread
and
•
1pcs hexagon locknut.
To install the drain fitting, firstly unscrew the drain pan from
the indoor unit. Locate the drain fitting into drain pan,
followed with locknut to secure the drain fitting to the drain
pan. Then refit the drain pan to the unit. Follow diagram
below to install the drain fitting in the correct way.
The locknut only requires hand tightening and then pinching
up with a spanner. Do not over tighten, else the threads may
strip from the nut and damage the tray.
Recommended minimum drainpi
pe diameter is 20mm or 3/4”.
The drainpipe material could be either copper or plastic. It is
not recommended to use flexible hose as it tends to kink
easily which might cause blockage and water to back up in
the unit.
Drainpipe must be leveled to permit free draining of
condensate from unit cooler.
Drain traps need to be installed for trouble free operation.
If the unit cooler is operated without the
drain trap
, warm
air with higher temperature will draw from outside to the
cold room. Thus, warm air will significantly reduce the cooler
capacity and may lead to ice formation in the drain pan.
If the temperature surrounding the drain line and trap is
below freezing (0
o
C), it must be wrapped with a drain line
heater. Drain pan coupling and drainpipe must be insulated
up to the external wall surface of the cool room. Make sure
the drain pan and drain line is free from debris to avoid
clogging and cause overflowing.
