McQuay MicroTech III RAH User Manual

58 McQuay OM 920-1
Alarms
When the High Pressure Circuit 1, 2, 3,4,5,6 problem occurs, the unit continues to operate but
cooling circuit is disabled. Note: The Circuit remains disabled until the high pressure switch
closes and the High Pressure Circuit 1 problem is manually cleared through the unit keypad or
via a network signal.
Sump Pump Fail
On evaporative cooling units if the sump pump is turned on but the pump status input remains
open after the Sump Pump Delay (default 30 seconds), the pump is turned off and cooling
remains off for one cooling stage time period before the controller tries again. If this condition
occurs three times between 2:00 AM of one day and 2:00 AM of the next day, the Sump Pump
Fail problem occurs. Mechanical cooling remains disabled until the Sump Pump Fail problem
is manually cleared through the unit keypad or via a network signal.
Entering Fan Temperature/Leaving Coil Temperature Sensor Problem
This alarm occurs when the Entering Fan Temperature/Leaving Coil Temperature sensor is
present and either shorted or open circuited for longer than the Sensor Alarm Delay (Default =
30 seconds). When this alarm occurs the unit continues to operate however dehumidification
operation is disabled until the sensor becomes reliable. The maximum DAT limit function
associated with Gas or Electric heat is also disabled until the sensor becomes reliable.
Return Air Sensor Problem
If the return air temperature sensor (RAT) is present and either shorted or open circuited for
longer than the Sensor Alarm Delay (default is 30 seconds), the Return Air Sensor problem
occurs. When the RAT Sensor problem occurs, the unit continues to operate with the following
modifications:
• Cooling Reset and Heating Reset revert to none if they are set to Return
• Control temperature source reverts from return to space if a space temperature sensor is
present and reliable
When the alarm condition is no longer present, the RAT Sensor problem automatically clears.
Space Sensor Problem
If the Space Sensor Present setting is set to Yes, a valid Space Temperature value is not
provided via a network signal and the local space sensor is shorted or open circuited longer
than the Sensor Alarm Delay (default is 30 seconds), the Space Temperature Sensor problem
occurs. When the Space Temperature Sensor problem occurs, the unit continues to operate
with the following modifications:
• Cooling Reset and Heating Reset revert to none they are set to Space
• Control Temperature Source reverts from space to return if a return air sensor is present and
reliable.
When the alarm condition is no longer present, the Space Temperature Sensor problem
automatically clears.
OAT Sensor Problem
If the outside air temperature sensor (OAT) is present, a valid OAT value is not provided via
the network and the OAT sensor is either shorted or open circuited for longer than the Sensor
Alarm Delay (default is 30 seconds), the Outside Air Sensor problem occurs. When the OAT
Sensor problem occurs, the unit continues to operate with the following modifications:
• Heating is not locked out due to High OAT
• Cooling is not locked out due to Low OAT
• Cooling Reset and Heating Reset revert to none if they are set to OAT
• Economizer is locked out due to high OAT
When the alarm condition is no longer present, the OAT Sensor problem automatically clears.

McQuay MicroTech III RAH Specifications

General

Brand	McQuay
Model	MicroTech III RAH
Category	Controller
Language	English