Unit Sequence of Operation by Mode
13 Unit Sequence of Operation by Mode
13.1 Cooling Mode
Energizing the “O” terminal energizes the unit reversing valve
thus placing the unit into cooling mode. The fan motor starts
when the “G” terminal is energized.
A fault condition initiating a lockout will de-energize the
compressor irrespective of which stage is engaged.
On straight cool units, cooling mode is always active and there
is no O signal (reversing valve).
13.2 Heating Mode
The first two stages of heating (Y1 & Y2) operate in the same
manner as cooling but with the reversing valve de-energized.
As the thermostat is satisfied, the compressors will remain on
until the th
ermostat stages are satisfied.
Once the thermostat is satisfied, the compressor shuts down and
the fan r
amps down to either fan-only mode or OFF over a span of
30 seconds.
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EC Series Heat Pumps — 8733841499 (2024/05)
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