AH - A 5
Air Handler
Sequence of Operation
Continuous Fan
Note: CONTINUOUS fan mode during COOLING
operation may not be appropriate in humid climates.
If the indoor air exceeds 60% relative humidity or
simply feels uncomfortably humid, it is recommended
that the fan only be used in the AUTO mode.
When a request is received without a Heat/Cool
Demand, the air handler control (AHC) will energize
the blower at the speed for Continuous Fan operation.
When the request is removed, the AHC will turn off
the blower immediately.
Proprietary Humidity Control - When enabled, this
feature will disable any blower off delays and disable
continuous fan mode when the indoor humidity is above
the dehumidification setpoint. This will help prevent
coil condensation from being evaporated back into the
air stream.
Note: This feature, ISU 0388, is not shown unless
some form of dehumidification control is selected.
Call for Cooling
(Non-communicating outdoor unit – A/C Only)
When a request for cooling is received, the AHC will
energize the blower and the Y1 relay to activate the
outdoor unit contactor. When the request to terminate
Cooling is received, the Y1 relay will be turned off and
the blower will be de-energized once any user selected
fan-off delays have expired.
Note: In Communicating Mode, the Air Handler will
not operate a non-communicating Heat Pump.
(Communicating outdoor unit A/C or Heat Pump)
When the request for cooling is received the AHC will
energize the blower. When the request to terminate
cooling is received, the blower will be de-energized
once any user selected fan-off delays have expired.
The Charge Assist™ Control in the outdoor unit will
control the sequence of the compressor(s) and the
outdoor fan speed.
Call for 2nd Stage Cooling
(Communicating A/C or Heat Pump)
When request for 2nd Stage Cooling is received the
AHC will change the blower speed to 2nd stage airflow.
When the request to terminate 2nd Stage Cooling is
received, the blower will return to 1st stage airflow.
Heating
(Electric Heat Only)
When the request for heat is received, the AHC will
energize the blower and heating contactors. The
number of heating stages needed is determined by
the Comfort Control. If a blower request for a higher
airflow is received, the AHC will energize the blower
at the higher airflow. When the request to terminate
heat is received, the AHC will turn off the heat
contactors and the blower will be de-energized.
Heat Pump Only Applications
(Communicating Heat Pump)
When the request for mechanical heat is received,
the AHC shall energize the blower. When the request
for mechanical heat is terminated, the AHC will de-
energize the blower once any user selected fan-off
delays have expired.
Note: In Communicating Mode, the Air Handler will
not operate a non-communicating Heat Pump.
Communicating Mode
To Next Page
Loading...
