The Heating Will Be Enabled Whenever; The Cooling Will Be Enabled Whenever; Reversing Valve; Supplemental Electric Heating Stage - FHP 641-224 User Manual

The heating will be enabled whenever:

 The fan output is on.
 AND the reversing valve is in heat mode (de-energized).

The cooling will be enabled whenever:

 The fan output is on.
 AND the reversing valve is in cool mode (energized).


Reversing valve:

The reversing valve is energized on a call for cooling and will remain energized until a call for
heating. Upon a call for heating, the reversing valve is de-energized and remains de-energized
until a call for cooling or a call for re-heat on units with humidity (on/off) control option. The
compressor will be disabled and remain off for 10sec after the reversing valve has changed
position.
Alarms will be provided as follows:
Compressor 1 Runtime Exceeded: Compressor 1 runtime exceeds a user definable limit (adj.).
Compressor 2 Runtime Exceeded: Compressor 2 runtime exceeds a user definable limit (adj.).

Supplemental Electric Heating Stage:

The controller will measure the zone temperature and stage the heating to maintain its heating
setpoint should the compressors not meet the heating demand. To prevent short cycling, the
stage will have a 5 minute delay allowing compressor stages to meet the needs of the space.
The heating will be enabled whenever:
 The heat pump is in heating mode.
 AND the zone temperature is below heating setpoint.
 AND the fan is on.
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