Safety Devices And The Upm Ii Controller | 19 - Bosch Greensource CDi TW Series Installation, Operation And Maintenance Manual

Greensource CDi Series TW Model
SAFETY DEVICES AND THE UPM II
CONTROLLER
The TW122 Model is equipped with the Unit
Protection Module II (UPM II).
Fig. 11 UPM II controller board
[1] Board Power Indicator
[2] UPM II Status LED Indicator (Fault Status)
[3] Circuit 1 Freeze Protection Temperature
Selection (R17)
[4] Circuit 2 Freeze Protection Temperature
Selection (R77)
[5] UPM II Board Settings
[6] Circuit 1 Freeze Connection
[7] Circuit 2 Freeze Connection
[8] 24VAC Power Input (R)
[9] Compressor Contactor 1 Output Circuit
[10] Compressor Contactor 2 Output Circuit
[11] High-Pressure Circuit 1 Switch Connections
[12] Call for Compressor (Y1 24VAC Input)
[13] Low-Pressure Circuit 1 Switch Connections
[14] Low-Pressure Circuit 2 Switch Connections
[15] Call for Compressor 2 (Y1 24VAC Input)
[16] High-Pressure Circuit 2 Switch Connections
[17] Condensate Overflow Sensor (Not applicable
for Water-to-Water Units)
[18] Dry Contact
[19] Chassis Ground Connection
Greensource CDi Series TW Model

Safety Devices and the UPM II Controller | 19

When a malfunction light is used for
diagnostic purposes, the connection is
made
terminals of the UPMII board. Shown in
Fig. 11.
The UPM II controls the compressor operations
and monitors the safety controls that protect the
unit.
Safety controls include the following:
• High-pressure switches located in the
refrigerant discharge lines and wired across
terminals HP1 and HP2 on the UPM II.
• Low-pressure switches located in the unit
refrigerant suction lines and wired across
terminals LP1 and LP2 on the UPM II.
• Water-side freeze protection sensors, mounted
close to the load and source condensing water
coils, monitor refrigerant temperature
between condensing water coils and thermal
expansion valves. If temperature drops below
or remains at freeze limit trip for 30 seconds,
the controller will shut down the compressors
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 R17
Freeze1 resistor and the R77 Freeze2 resistor
located on top of DIP switch SW1 (Refer to Fig.
5, item [3] for resistor location), refer to Fig. 6
for sensor location.
The UPM II Board Dry Contacts are Normally
Open (NO).
For Reference
Only
Fig. 12 Sensor location
Subject to change without prior notice
at the dry contact connection
8733954853 (2020/04)