Bosch TW Series - Safety Devices and the UPM Controller

Electrical | 7TW Series Water to Water
6720220047 (2016/02)Revised 02-16
Safety Devices and the UPM Controller
Figure # 4
[1] Board Power Indicator
[2] UPM Status LED Indicator
[3]Water Source Coil Freeze Protection Temperature
Selection [R30]
[4] Load Water Coil Freeze Protection Temperature
Selection [R24]
[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
[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 (not applicable on
TW)
[16] Dry Contact
[17] UPM Ground Standoff
The TW Series has an optional 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 Freeze1
resistor located on top of DIP switch SW1 (Refer to
Figure #4, item [3] for resistor location), Refer to
Figure #5 for sensor location
.
Figure # 5
If the unit is being connected to a thermostat with a
malfunction light, this connection is made at the unit
malfunction output or relay. Refer to Figure #4.
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 made.
1
2
3
4
5
6
7
9
10
11
1213
17
14
15
16
8
If the thermostat is provided with a malfunction light
powered off of the hot (R) side of the transformer,
then the thermostat malfunction light connection
should be connected directly to the (ALR) contact on
the unit’s UPM board.
UPM Board Dry Contacts are Normally Open (NO)
NOTICE: If unit is employing a fresh water
system (no anti-freeze protection), it is
extremely important to have the Freeze1
R30 resistor set to 26°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.
For Reference
only