Carrier 30HH - Manual (Page 21)

Carrier
INSTALLATION
30HH,HJ
Liquid Charging Method
Liquid charge the units thru the condenser liquid
line shut-off valves.
1. Backseat condenser liquid line shut-off valve.
2. Connect a refrigerant cylinder loosely to the
gage connection of the condenser liquid line
shut-off valve. Purge the charging line and
tighten the connections.
3. Weigh the refrigerant cylinder (if possible).
4. Front seat the condenser liquid shut-off valve.
5. if the system has been dehydrated and is
under vacuum, break vacuum with refriger­
ant (Gas charge). Build system pressure to
58 psi for R 22 (32 F). Invert refrigerant
cylinder
so that liquid refrigerant will be
charged.
6. Allow the compressor to cycle on the low
pressure cut-out until sufficient pounds of
refrigerant have been added (Table 6).
7. When the unit is sufficiently charged, close
the cylinder valve, backseat the liquid line
shut-off valve, and remove the charging ap­
paratus. Replace the cap in the liquid line
shut-off valve.
NOTE: Where it is impossible to weigh
the refrigerant cylinder, the initial re­
frigerant
charge must be an approxi­
mation. After it has been added, back­
seat the liquid line shut-off valve and
allow the unit to operate. A clear flow
of liquid in the liquid-moisture indica­
tor, indicates a satisfactory charge.
If the charge is not sufficient, add re­
frigerant until a clear flow of liquid
show in the glass.
CAUTION: Be careful not to overcharge
the system. Overcharging results in:
(a) Higher discharge pressure with
higher cooling water consumption.
(b) Possible compressor damage.
(c) Higher power consumption.
OIL CHARGE
The 30HH,HJ units are charged with oil at the
factory (Table 2). Because of added piping with
evaporative condenser models, it may be neces­
sary to add oil at the job site. Observe the oil
level closely at startup and add oil, if required,
to bring the level in the crankcase to the middle
of the bull's-eye during steady operation.
To Add Oil
1. Close suction shut-off valve and pump down
crankcase to 2 psig. (Low pressure cut-out
must be shorted.) Wait a few minutes and
repeat
as needed until pressure remains at
2 psig.
2. Remove oil fill plug to the right of the bull's-
eye and add oil thru plug hole.
3. Replace plug.
4. Run compressor for about 20 minutes and
check the oil level.
CAUTION: To insure trouble free oper­
ation, use only Carrier approved com­
pressor oil, Specification No. PP-33-2.
Do not re-use oil that has been drained
out, or oil that has been left open to the
atmosphere.
To Remove Oil
1. Pump down compressor to 2 psig gage.
2. Loosen the 1/4” pipe plug in compressor
base and allow the oil to seep out past the
threads of the plug.
CAUTION: The crankcase will be under
slight pressure. Be careful not to re­
move the plug; the entire oil
may be lost.
charge
CHECK THE CONTROLS
Expansion Valve
The thermal expansion valves control the flow
of liquid refrigerant by maintaining constant
superheat of the vapor leaving the cooler. They
are pre-set at the factory to maintain a super­
heat of 8 F. Do not attempt to adjust them unless
you are certain it is absolutely necessary.
Safety Thermostat Adjustment
The safety thermostat is of non-cycling, manual
reset type. It has an adjusting dial with a stop
set at 36 F for normal chilled water applica­
tions, but can be readjusted for a lower stop if
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