During a lock out, the LOR-2 contacts are closed, energizing
the X terminal on the terminal board for lighting a lock out warn-
ing light.
Resetting the Lock Out
The lock out may be reset by:
•
Turning the thermostat switch to OFF, or
•
Momentarily adjusting the cooling set point to its maxi-
mum allowed value.
If the unit does not resume operation after the anti-short cycle
timer expires or if it continues to lock out after resuming opera-
tion, call a service technician to diagnose and repair the unit.
CAUTION: Repeatedly resetting the lock out may cause dam-
age to the unit.
Second Stage of Cooling
The second stage of cooling will only be enabled if the first
stage of cooling is on, closing auxiliary contact 1M-AC1. A call
for cooling a terminal Y2 energizes RY2, closing contact RY2-
1, and energizing time delay relay 4TR if contact 1M-AC1 is
closed. If time delay relay 4TR is satisfied, it will energize its ou-
put terminal Y2, which is to connect to 4 second time delay re-
lay TDR. After 4 seconds, TDR energizes compressor 2
contactor 2M.
When 2M is energized on HDHB240 units, auxiliary 2M-AC1 is
closed, powering terminal 2 for opening the stage 2 solenoid in
air handlers which feature a stage 2 solenoid.
LOW AMBIENT COOLING
The following accessories are available to provide low ambient
operation to 0°F
SAFETY FEATURES
1. The compressor is protected against over current and ex-
cessive temperature as described in the Sequence of Op-
eration.
2. The compressor is equipped with a crankcase heater to
discourage refrigerant migration into the compressor sump
during the “OFF” cycle.
3. The condenser fan motors have auto-reset internal protec-
tion.
4. The secondary of every transformer is grounded.
5. Every unit is protected by high and low-pressure controls
Unitary Products Group
13
035-17393-000 Rev. A (0501)
CAUTION:
DO NOT ATTEMPT TO START THE COMPRESSOR WITHOUT
AT LEAST 8 HOURS OF CRANKCASE HEAT OR COMPRES-
SOR DAMAGE WILL OCCUR.
2LA04704225
208/230 VOLTS
2LA04704346
460 VOLTS
2LA04704458
575 VOLTS
SECURE OWNER'S APPROVAL: When the system is functioning properly, secure the owner's approval. Show him the location of
all disconnect switches and the thermostat. Teach him how to start and stop the unit and how to adjust temperature settings within
the limitations of the system.
MAINTENANCE
CLEANING CONDENSER SURFACE
Dirt should not be allowed to accumulate on the condenser coils
or other parts in the condenser air circuit. Clean as often as nec-
essary with a brush, vacuum cleaner attachment or other suit-
able means.
LUBRICATION
The fan motors for these condensing units are equipped with
factory lubricated and sealed ball bearings. They do not require
any maintenance.
COMPRESSOR REPLACEMENT
Contact the local UPG Distribution Center for compressor or parts.
