16
8.2 Defrost Termination
Once a defrost is initiated, the defrost will continue until fourteen minutes has
elapsed or the coil temperature has reached the terminate temperature. The termi-
nate temperature is factory set at 70°F, although the temperature can be changed
to 50°F, 60°F, 70°F or 80°F by relocating dip switches on the ICC.
NOTE:
An optional “Noise Abatement Time“ can be selected via the communicating
thermostat or the Service Tool program. When 5 second Noise Abatement is select-
ed, the compressor will shut down for 5 seconds when unit goes into or comes out
of defrost.
8.3 Temperature Sensors
The coil sensor is clipped to the top tube on the outdoor coil at the point fed by the
distribution tubes from the expansion device (short 3/8” dia. tube).
If the ambient sensor fails the defrost control will initiate a defrost every 34 minutes
in heat mode with the coil temperature below 35°F.
8.4 Defrost Test Mode
The defrost test mode is initiated by pressing pushbutton SW2 for 1 second
with the unit running in HP mode. Upon release of pushbutton SW2, the unit will
go into defrost until termination temperature is achieved or 14 minutes has
expired. Pressing SW2 while in Defrost Test Mode will terminate test mode.
8.5 Trouble Shooting Demand Defrost
Set the indoor thermostat select switch to heat and initiate a call for heat.
Press SW2 to put the unit into defrost. If the unit goes into defrost and comes back
out of defrost, the indication is that the control is working properly.
9.0 COMPRESSOR CRANKCASE HEAT (CCH)
CCH is standard on these models due to refrigerant migration during the off cycle
that can result in a noisy start up.
Crankcase Heater Operation:
Supplemental crankcase heat is required to prevent refrigerant migration in systems
with relatively high system refrigerant charges.
The crankcase heater control is integrated into the ICC and is designed for maxi-
mum energy savings and uses a 120-minute off delay.
Summary of operation:
• The crankcase heater is off whenever the compressor is running.
• Once the compressor turns off, the crankcase heater control (CCH) begins the
two-hour timer countdown.
• If the compressor stays off for two hours, the CCH turns on the crankcase heater.
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.)
10.0 HARD START COMPONENTS
Factory-installed start components are standard on all models.
Summary of Contents for PRL-series
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