Unit installation

36 OMRCPMICRO
Other Conditions
Low source water temperature (THRs only)
This is not an alarm condition. This condition is applicable only when the unit operation of "ChlTmp" is
selected from Menu 23 and the unit is run in heating mode. If the leaving evaporator water temperature drops
below the "LoSourcT" alarm setpoint, all running compressors will run unloaded. The forced condition will
continue until the leaving evaporator water temperature rises above the"LoSourcT"setpoint or until an
appropriate alarm condition is logged. This is an autoclearing condition. No alarm display is associated with
this condition since it is not a true alarm condition, merely a safeguard.
Table 6 shows all of the circuit and system alarms and prealarms. The default values for adjustable set points
are reflected in the table.
Table 6, MicroTech safety systems
Safety Description
Adjustment
Range
ALR
Setpoint
WHR
Setpoint
THR
Setpoint
Alarm
Condition
Alarm
Reset
Type
Mechanical high pressure - 400 psig 380 psig 400 psig Circuit Alarm Manual
High condenser pressure 280-425 psi 380 psig 360 psig 380 psig Circuit Alarm Manual
High condenser stage down - 360 psig 340 psig 360 psig Circuit Pre-alarm Auto
High condenser stage hold - 350 psig 330 psig 350 psig Circuit Pre-alarm Auto
Low evaporator pressure - 34 psig 34 psig 34 psig Circuit Alarm Manual
Low oil differential/power - 9 psig 9 psig 9 psig Circuit Alarm Manual
ChW freeze protection N/A, 0.5-40°F 34°F 34°F 34°F System Alarm Manual
Freeze stat protection 20-54 psi 54 psig 54 psig 54 psig Circuit Alarm Manual
Freeze stat stage down - 54 psig 54 psig 54 psig Circuit Pre-alarm Auto
Volts ratio protect - ± 7.5% ± 7.5% ± 7.5% System Alarm Manual
Loss of water flow - - - - System Alarm Auto
Compressor mtr protect - - - - Circuit Alarm Auto
Incomplete pumpdown - 34 psig 34 psig 34 psig Circuit Alarm Manual
Bad pressure sensor - - - - Circuit Alarm Manual
Bad lvg water sensor - - - - System Alarm Manual
Bad phase/voltage - - - - System Alarm Auto
Low source water temp 20-75°F N/A N/A 40°F System N/A Auto