Electronic Control Sequence Of Operation - Friedrich KUHL R-410A Service Manual

ELECTRONIC CONTROL SEQUENCE OF OPERATION

Compressor and Reversing Valve Control
Cooling
Heat - Heat Pump
Heat - Electric
Fan Only
* The Reversing valve stays in the last state until a call for heat or cooling (see fi gure below)
Cooling Mode
Once the ambient temperature rises past the cool demand threshold (Cool Set Point + 1.5 ˚F) (see fi gure below), and
the compressor is not locked out, the cooling cycle begins. As shown in the fi gure below, the fan is started 5 seconds
prior to the compressor. Once the ambient temperature has been lowered to the cool set point (Cool Set Point minus
.25 ˚F), the cooling cycle starts to terminate by shutting off the compressor. After a 30 seconds delay, the fan is shut
off. (See fi gure below for graphic details)
Active Mode
Compressor Operation:
The reversing valve only changes when required
to provide cooling or heat pump. The RV valve
stays in it's last state until required to change.
Compressor
Reversing Valve State
De-Energized
On
On
Off
Off
Energized
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