Unit installation

OMRCPMICRO 35
System Alarm Conditions
The "System Alarm Conditions" are those alarms which are common to both refrigeration circuits and require
all compressors to be temporarily shut off or locked out, whichever applies. The following alarm conditions are
checked continuously during all modes of operation by the controller. If one of the following alarm conditions
is detected, the mode of the controller will switch to "Off: Alarm". The controller disables all compressor
operation by turning off all Compressor Enable Outputs. Alarm Output #0 will be turned on to notify the
operator of the alarm condition. The red "Alarm Status" light on the front of the control panel will be solid on
the alarm condition and the MicroTech display will show the current alarm condition.
The chiller must have the manual reset system alarm conditions cleared before normal operation can resume. If
the alarm which occurred is an autoclearing alarm, once the condition has corrected, the chiller will resume
normal operation provided the anti-cycle timers have cleared and sufficient load exists.
Loss of water flow
Water flow must be present when the controller is attempting to provide capacity cooling or heating. Chilled
water flow or condenser water flow are not required during pumpdown, manual off, system off, or other off
conditions.
A time delay of 1.7 to 3.2 seconds has been built into this alarm function to accommodate momentary loss of
flow due to air bubbles or pressure fluctuations in the water piping. The alarm shows up as
"LossofWaterFlow". This alarm is logged when the evaporator flow is interrupted on chillers and Templifier
heat pumps. The alarm is also logged when the condenser flow on Templifier heat pumps is interrupted if a
flow switch is present.
The chiller status on this alarm will read "Wait for Flow" instead of "Off: Alarm". This is an autoclearing alarm.
Bad phase/voltage
This alarm is only valid if a phase volt monitor (PVM) is wired into MicroTech.
Upon detecting an opening of the normally closed PVM contacts, compressors are immediately de-energized
by the PVM device. The controller will open compressor enabled outputs and log the alarm
"BadPhase/Voltage". This is an autoclearing alarm.
Chilled water freeze protection
If the leaving chilled water temperature falls below the operator adjustable Chilled Water Freeze Alarm Setpoint
(Frze H2O), the unit is shut down and the alarm "WaterFreeze Prot" is logged. There is no time delay—just one
sampling of water at this low temperature will shut down the machine.
Volts ratio protection
The controller monitors the output of the internal 5VDC power supply into analog input #5. If the
microprocessor is not receiving an acceptable volts ratio signal—between 4.15 and 4.94VDC—the unit will be
shut down on the alarm "BadVoltsRatioSen". This alarm must be manually cleared before operation can
resume.
Note: This voltage is used for pressure transducers. If the voltage is not accurate, the transducer
output will not be accurate.
Bad leaving water sensor
If the leaving water sensor fails, causing a short or open, the alarm "Bad Lvg Water Sen" will be logged and
the unit shut down. The unit will only shut down when the control leaving water sensor is bad. For chillers
and Templifiers operated in chill mode, the control sensor is the leaving evaporator sensor. For Templifiers
operated in heat mode, the leaving condenser sensor is the control sensor.