Installation guide

625 - 50 psig between suction (low side) and discharge (high side)
to allow pressure equalization.
Internal Current and Temperature Sensitive Overload
The control resets automatically when internal compressor motor
temperature drops to a safe level (overloads may require up to 45
minutes to reset). When an internal overload is suspected of being
open, check by using an ohmmeter or continuity tester.
Pumpdown Procedure
The system may be pumped down in order to make repairs on the
low side without losing complete refrigerant charge.
[]NIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Never open system to atmosphere while it is under a
vacuum.
When system must be opened for service, recover refrigerant, break
vacuum with dry nitrogen before opening system.
1. Attach pressure gage to suction service valve gage port.
2. Frontseat the mixed-phase line valve.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
The unit coils hold only the factorydesignated amount of
refrigerant. Additional refrigerant may cause units to relieve
pressure through the compressor internal pressure relief
valve (indicated by a sudden rise of suction pressure) bet\_re
suction pressure reaches 20 psig. If this occurs, shut off unit
immediately then frontseat the suction valve and remove
and recover excess refrigerant following accepted practices
3. Start unit and run until suction pressure reaches 20 psig.
4. Shut unit off and frontseat suction valve.
5. De-pressurize low side of unit and recover refrigerant fol-
lowing accepted practices.
High-Pressure Switch
The high-pressure switch, located on discharge line, protects
against high discharge pressures caused by such events as
overcharge, condenser-fan motor failure, system restriction, etc. It
opens on pressure rise at about 650 -- 10 psig. If system pressures
go above this setting during abnormal conditions, the switch
opens.
PERSONAL INJURY HAZARD
Failure to follow this warning could result in personal iniury
or death.
DO NOT attempt to simulate these system abnormalities -
high pressures pose a serious safety hazard.
The high-pressure switch is checked with an ohmmeter. If system
pressure is below 625 psig switch shows continuity.
Crankcase Heater
The crankcase heater prevents refrigerant migration and
compressor oil dilution during shutdown when compressor is not
operating. If the crankcase heater is de-energized for more than 6
hours, both compressor service valves must be closed.
The crankcase heater is powered by the high-voltage power of the
unit. It is connected across the line side of the contactor and is
thermostatically controlled.
PERSONAL INJURY HAZARD
Failure to follow this warning could result in personal
iniury or death.
Use extreme caution when troubleshooting this device as
line voltage is continually present.
To troubleshoot:
1. Apply voltmeter across crankcase heater leads to see if heat-
er voltage is on. Do not touch heater. Carefully feel area
around crankcase heater; if warm, crankcase heater is flmc-
tioning.
2. With power off and heater leads disconnected, check across
leads with ohmmeter. Do not look for a specific resistance
reading. Check for resistance or an open circuit, and change
heater if an open circuit is detected.
Service Valves
The service valves in the outdoor unit come from the factory
frontseated. This means the refrigerant charge is isolated from the
line-set connection ports. To prevent damage to the valve, use a
wet cloth or other accepted heat sink material on the valve before
brazing.
The service valve cannot be field repaired, therefore, only a
complete valve or valve stem seal and service port caps are
available for replacement.
Defrost Controls
The defrost process is controlled by a defrost thermostat switch, an
accumulated compressor run timer and an adaptively optimized
defrost interval.
The accumulated compressor run timer keeps running when the
defrost thermostat switch is closed and the compressor is running
in heating mode. When the compressor turns off, the timer stops
running but retains its current value. If the compressor turns on
later, the timer will resume running from its retained value. When
the defrost thermostat switch is open, the accumulated compressor
run timer resets to zero.
When the accumulated compressor timer reaches the defrost
interval, defrost process is initiated. When in defrost, if the defrost
thermostat switch becomes open, the defrost process will terminate.
If the defrost time has reached 10 minutes and the defrost
thermostat switch is still closed, the defrost process will terminate.
If the defrost process lasts more than 3 minutes, the defrost interval
will increase by 5 minutes. If the defrost process lasts more than 7
minutes, the defrost interval will decrease by 5 minutes. The
allowed range for defrost interval is 30 - 90 minutes. When a unit
is powered up, the defrost interval takes the default value of 90
minutes.
10