Safety Devices And The Upm Controller - Bosch ES025 Installation And Maintenance Manual

ES Series
SAFETY DEVICES AND THE UPM
CONTROLLER
1
2
3
4
5
7
Figure # 13
[1] Board power indicator
[2] UPM Board LED indicator
[3] Water coil freeze protection temperature
selection
[4] Air coil freeze protection temperature selection
[5] UPM board settings
[6] Water coil freeze connection
[7] Air coil freeze connection
[8] LCD connection
[9] 24VAC power hot
[10] To compressor contactor
[11] High pressure switch connection
[12] Call for compressor
[13] Low pressure switch connection
[14] 24VAC power common
NOTE: If the unit is being connected to a
thermostat with a malfunction light, this
connection is made at the unit malfunction
output or relay.
Each unit is factory provided with a Unit Protection
Module (UPM) that controls the compressor
operation and monitors the safety controls that
protect the unit.
Safety controls include the following:
ES Series
11
13 12
8 10
9

Safety Devices and the UPM Controller | 11

• 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.
UPM Board Dry Contacts are Normally Open
(NO)
• 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 R42 resistor located on top
of DIP switch SW1. (Figure #11)
•
Figure # 14
• The optional condensate overflow protection
sensor (standard on horizontal units) is
located in the drain pan of the unit and
connected to the 'COND' terminal on the UPM
board. (Figure #10)
UPM Board Factory Default Settings
TEMP
LOCKOUT
RESET
ALARM
TEST
HOT/DRY ALARM
26°F
2
Y
PULSE
NO
NO
T111970291 (2015/01)