Safety Devices and the UPM Controller Overview
If the thermostat is provided with a malfunction light powered
off of the common (C) side of the transformer, a jumper
between “R” and “COM” terminal of “ALR” contacts must be
installed.
Each unit is factory equipped with a UPM that controls the
compressor operation and monitors the safety controls that
protect the unit.
Safety controls include the following:
• High-pressure switch located in the refrigerant discharge line
and wired across the HPC (High-Pressure Switch
Connection) terminals on the UPM.
• Low-pressure switch located in the unit refrigerant suction
line and wired across the LPC (Low-Pressure Switch
Connection) terminals (LPC1 and LPC2) on the UPM.
• Waterside freeze protection sensor (FREEZE 1), mounted
close to condensing water coil (
Refer to Fig. 19), monitors
refrigerant temperature between condensing water coil and
thermal expansion valve. If temperature drops below or
remains at freeze limit trip for 120 seconds, the controller
will shut down the compressor and enter into a soft-lockout
condition. The default freeze limit trip is 25°F; however, this
can be changed by flipping DIP switch SW1. (
Refer to Fig.
18, item [10].)(
Refer to Fig. 21.)
The UPM Board Dry Contacts are Normally Open (NO).
NOTICE
If the unit is employing a fresh water system (no anti-freeze
protection), it is extremely important to have the Freeze 1 set
to 25°F (DIP Switch SW1 set to OFF) 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.
• Air coil freeze protection sensor (FREEZE 2), mounted
between the thermal expansion device and the air coil
(
Refer to Fig. 20), monitors refrigerant temperature
between the air coil and thermal expansion valve. If
temperature drops below or remains at the freeze limit trip
for 30 seconds, the controller will shut down the compressor
and enter into a soft-lockout condition. The default freeze
limit trip is 25°F.
Fig. 19 Waterside Freeze Protection Sensor Location (FREEZE 1)
Note: Vertical (VT) Configuration Depicted
Fig. 20 Air Coil Freeze Protection Sensor Location (FREEZE 2)
Note: Vertical (VT) Configuration Depicted
• The condensate overflow protection sensor is located in the
drain pan of the unit and connected to the “COND” terminal
on the UPM board. (Refer to Fig. 18, item [8].)
32 |
CL Series Heat Pumps — 8733838716 (2024/05)
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