Safety Devices And The Upm Controller Overview - Bosch QV Series Installation, Operation And Maintenance Manual

QV Series Heat Pumps
SAFETY DEVICES AND THE UPM
CONTROLLER OVERVIEW
QV models are equipped with the Unit Protection
Module (UPM) that controls the compressor
operation and monitors the safety.
Fig. 16 UPM controller board
[1] Board Power Indicator
[2] UPM Status LED Indicator (Fault Status)
[3] Water Source Coil Freeze Protection
Temperature Selection (R30, FREEZE 1)
[4] Air Coil Freeze Protection Temperature
Selection (R24, FREEZE 2)
[5] UPM Board Settings
[6] Water Coil Freeze Connection (FREEZE 1)
[7] Air Coil Freeze Connection (FREEZE 2)
[8] LCD Unit Display Connection
[9] 24VAC Power Input
[10] Compressor Contact Output
[11] High-Pressure Switch Connection
[12] Call for Compressor (Y1)
[13] Low-Pressure Switch Connection
[14] 24VAC Power Common
[15] Condensate Overflow Sensor
[16] Dry Contact
[17] UPM Ground Standoff
When a malfunction light is used for
diagnostic purposes, the connection is
made at the dry contact connection
terminals of the UPM board.
QV Series Heat Pumps

Safety Devices and the UPM Controller Overview | 27

If the thermostat is provided with a
malfunction
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, mounted
close to condensing water coil, monitors
refrigerant temperature between condensing
water coil and thermal expansion valve or
capillary tube. If temperature drops below or
remains at 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 26°F; however, this can be
changed to 15°F by cutting the R30 (Freeze 1)
resistor located on top of DIP switch SW1
(Refer to Fig. 16, item [3] for resistor location).
Refer to Fig. 17 for sensor location.
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
R30 resistor set to 26°F (do not cut R30
resistor) 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.
Subject to change without prior notice
light powered off of the
8733829041 (2021/07)