34
Stg4 Diff.
H/C
Stages
Locked =
YES
H/C
Stages
Locked =
NO
3rd stage
ON
1st stage
ON
2nd stage
ON
4th stage
ON
3rd stage
ON
1st stage
ON
2nd stage
ON
4th stage
ON
2nd stage
OFF
3rd stage
OFF
4th stage
OFF
1st stage
OFF
Stg4 Differential
1st stage
OFF
2nd stage
OFF
3rd stage
OFF
4th stage
OFF
SET
POINTS:
SP -1.5
SP -1.0
SP -0.5
SP
SP +0.5
SP -2.0
Stg1 Differential
Stg3 Differential
Stg2 Differential
SP -2.5
SP -3.0
SP -3.5
Stg1 Differential
Stg3 Differential
Stg2 Differential
Figure 21. Heating - dual fuel - 4 stage (2 compressor / 2 backup)