Page 48
SEQUENCE OF OPERATION LDT078-150 (continued)
Outdoor Ambient Temperature W1 Demand W2 Demand
Above Balance Point
*Temperature Setting**
Compr. 1 & 2 On*
Gas Heat High
Below Balance Point
Temperature Setting**
Gas Heat Low
Gas Heat High
*L1 and L2 reversing valves are de-energized with a heating demand. The heat pump
will heat only, not cool.
**Balance Point temperature setting can be adjusted using the following mobile service
(HP DF
First Stage Heat - OD Temp ABOVE
1 -
2 -
compressors contactors K1, K2 are energized.
3 - K1-1 and K2-1 close energizing compressor B1 and B2. K1 and K2
auxiliary switch open de-energizing crankcase heaters.
4 -
First Stage Heat - OD Temp BELOW
gas heat.
6 - See sequence of operation for gas heat.
NOTE - For rst stage heat, the OD temp is only checked upon a change
in demand. The controller will continue with the selected heat source until
a change in heating demand is received.
NOTE - If the OAT sensor on an LHT unit fails, the controller will assume
OAT is not suitable for HP and will use gas heat.
Second Stage Heat - Regardless of OD Temperature
7 -
controller will activate electric heat in addition to heat pump operation.
8 - See sequence of operation for gas heat.
Defrost Mode:
-
between the outdoor coil and outdoor air temperature. Defrost is also initiated
reaches six hours.
Note - Only one refrigerant circuit will go into defrost at a time.
To Next Page
Loading...
