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Table 9 — UPM Board Fault Blink Codes
Safety controls include the following:
• High-pressure switch located in the refrigerant discharge
line and wired across the HPC terminals on the UPM
board.
• Low-pressure switch located in the unit refrigerant suc-
tion line and wired across terminals LPC1 and LPC2 on
the UPM board.
• UPM board dry contacts are normally open (NO).
• Water-side freeze protection sensor, mounted close to
condensing water coil, monitors refrigerant temperature
between condensing water coil and thermal expansion
valve. If temperature drops below or remains at freeze
limit trip for 30 seconds, the controller will shut down
the compressor and enter a soft lockout condition. The
default freeze limit trip is 30°F, however this can be
changed to 15°F by cutting the R30 or Freeze1 resistor
located on top of DIP switch SW1. Refer to Fig. 20, Item
3 for resistor location. If unit is employing a fresh water
system (no anti-freeze protection), it is extremely
important to have the Freeze1 R30 resistor set to 30°F in
order to shut down the unit at the appropriate leaving
water temperature and protect heat pump from freezing if
a freeze sensor is included.
• Evaporator freeze protection sensor, mounted between
the thermal expansion device and the evaporator, moni-
tors refrigerant temperature between the evaporator coil
and thermal expansion valve. If temperature drops below
or remains at freeze limit trip for 30 seconds, the control-
ler will shut down the compressor and enter into a soft
lockout condition. The default freeze limit trip is 30°F.
(See Fig. 21 and 22.)
• The condensate overflow protection sensor is located in
the drain pan of the unit and connected to the ‘COND’
terminal on the UPM board.
Fig. 22 — No Freeze Protection Sensor
The UPM board includes the following features:
Anti-short Cycle Timer — A 5-minute delay on break timer
prevents compressor short cycling.
Random Start — Each controller has an unique random start
delay ranging from 270 to 300 seconds on initial power up to
reduce the chance of multiple units simultaneously starting at
the same time after power up or after a power interruption, thus
avoiding creating large inrush current.
Low Pressure Bypass Timer — If the compressor is running
and the low-pressure switch opens, the controller will keep the
compressor ON for 120 seconds. After 2 minutes if the low-
pressure switch remains open, the controllers will shut down
the compressor and enter a soft lockout. The compressor will
not be energized until the low-pressure switch closes and the
anti-short cycle time delay expires. If the low-pressure switch
opens 2 to 4 times in 1 hour, the unit will enter a hard lockout.
In order to exit hard lockout power to the unit would need to be
reset.
Brownout/Surge/Power Interruption Protection — The
brownout protection in the UPM board will shut does the com-
pressor if the incoming power falls below 18 VAC. The com-
pressor will remain OFF until the voltage is above 18 VAC and
ANTI-SHORT CYCLE TIMER (300 seconds) times out. The
unit will not go into a hard lockout.
Malfunction Output — Alarm output is normally open (NO)
dry contact. If pulse is selected the alarm output will be pulsed.
The fault output will depend on the DIP switch setting for
ALARM. If it is set to CONST, a constant signal will be pro-
duced to indicate a fault has occurred and the unit requires in-
spection to determine the type of fault. If it is set to PULSE, a
pulse signal is produced and a fault code is detected by a re-
mote device indicating the fault. The remote device must have
a malfunction detection capability when the UPM board is set
to PULSE.
LED
BLINKS
FAULT
FAULT CRITERIA
0
None
All fault conditions nominal
1
High Pressure
Refrigerant discharge
pressure has exceeded
600 psig
2
Low Pressure
Refrigerant suction pressure
has fallen below 40 psig
3
Water Coil Freeze
Condition
Refrigerant temperature to the
water coil has fallen below
30 F for 30 seconds
4
Condensate Overflow
Condensate levels in the unit
drain pan are too high
5
Air Coil Freeze
Condition
Refrigerant temperature to the
air coil has fallen below
30 F for 30 seconds
6
Brown Out
Control voltage has fallen
below 18 VAC
Fig. 21 — Water-Side Freeze Protection Sensor
WARNING
If unit is employing a fresh water system (no anti-freeze
protection), it is extremely important to have the Freeze1
R30 resistor set to 30°F in order to shut down the unit at the
appropriate leaving-water temperature and protect your
heat pump from freezing if a freeze sensor is included.