Friedrich KUHL R-410A - Manual (Page 24)

23
ELECTRONIC CONTROL SEQUENCE OF OPERATION
Compressor and Reversing Valve Control
Cooling De-Energized
Energized
On
On
Off
Off
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)
Compressor Operation:
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)
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.
Active Mode Compressor Reversing Valve State