Safety Devices And The Upm Controller - Bosch LM Split CS Series Installation, Operation And Maintenance Manual

16 | Safety Devices and the UPM Controller

Safety Devices and the UPM Controller
Fig. 6 Typical 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] Load Water Coil Freeze Protection
Temperature Selection (R24, FREEZE 2)
[5] UPM Board Settings
[6] Source Coax Freeze Connection (FREEZE 1)
[7] Load Coax Freeze Connection (FREEZE 2)
[8] LCD Unit Display Connection
[9] 24VAC Power Input (R)
[10] Compressor Contact Output
[11] High-Pressure Switch Connection
[12] Call for Compressor (Y1 Output)
[13] Low-Pressure Switch Connection
[14] 24VAC Power Common (C)
[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
terminals of the UPM board. Refer to Fig. 6.
8733827906 (2021/11)
Each unit is provided with a factory-installed Unit
Protection Module (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
terminals on the UPM.
• Low-pressure switch located in the unit
refrigerant suction line and wired across
terminals LPC1 and LPC2 on the UPM.
• 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 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 or FREEZE 1 resistor
located on top of DIP switch SW1 (Refer to Fig.
6, item [3] for resistor location), refer to Fig. 7
for sensor location.
connection
Subject to change without prior notice
LM Split CS Series Heat Pump
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
alarm (ALR) contacts must be installed.
The UPM Board Dry Contacts are Normally
Open (NO).
LM Split CS Series Heat Pump