14.3 CONTROL WIRING
(See Figure 3)
If the low voltage control wiring is run in conduit with the power supply, Class I insu-
lation is required. Class II insulation is required if run separate. Low voltage wiring
may be run through the insulated bushing provided in the 7/8 hole in the base
panel, up to and attached to the pigtails from the bottom of the control box. Conduit
can be run to the base panel if desired by removing the insulated bushing.
A thermostat and a 24 volt, 40 VA minimum transformer are required for the control
circuit of the condensing unit. The furnace or the air handler transformer may be
used if sufficient. See the wiring diagram for reference. Use 18-gauge thermostat
wire only.
15.0 FIELD INSTALLED ACCESSORIES
15.1 COMPRESSOR CRANKCASE HEAT (CCH)
While scroll compressors usually do not require crankcase heaters, there are
instances when a heater should be added. Refrigerant migration during the off cycle
can result in a noisy start up. Add a crankcase heater to minimize refrigerate migra-
tion, and to help eliminate any start up noise or bearing “wash out.”
NOTE:
The installation of a crankcase heater is recommended if the system charge
exceeds the values listed in Table 6.
All heaters are located on the lower half of the compressor shell. Its purpose is to
drive refrigerant from the compressor shell during long off cycles, thus preventing
damage to the compressor during start-up.
At initial start-up or after extended shutdown periods, make sure the heater is ener-
gized for at least 12 hours before the compressor is started. (Disconnect switch on
and wall thermostat off.)
15.2 TIME DELAY CONTROL (TDC)
The time delay (TDC) is in the low voltage control circuit. When the compressor
shuts off due to a power failure or thermostat operation, this control keeps it off at
least 5 minutes which allows the system pressure to equalize, thus not damaging
the compressor or blowing fuses on start-up.
17
TABLE 6
MAXIMUM SYSTEM CHARGE VALUES – 13 SEER
13 SEER
Compressor
Charge Limit
Charge Limit
Model
Model
Without Crankcase
Without Crankcase
Size
Number
Heat (1 Phase)
Heat (3 Phase)
18
ZP16K5E
9.6 lbs.
24
ZP20K5E
9.6 lbs.
30
ZP24K5E
9.6 lbs.
36
ZP31K5E
9.6 lbs.
8 lbs.
42
ZP36K5E
12 lbs.
10 lbs.
48
ZP42K5E
12 lbs.
10 lbs.
60
ZP51K5E
12 lbs.
10 lbs.
MAXIMUM SYSTEM CHARGE VALUES – 14.5 SEER
14.5 SEER
Compressor
Charge Limit
Model
Model
Without Crankcase
Size
Number
Heat (1 Phase)
18
ZP16K5E
9.6 lbs.
24
ZP20K5E
9.6 lbs.
30
ZP24K5E
9.6 lbs.
36
ZP31K5E
9.6 lbs.
42
ZP34K5E
12 lbs.
NOTE:
Model sizes 48 and 60 have a factory installed crankcase heater.
