LAARS Heating Systems
Page 60
Model
Gas Type
High Fire CO
2
Low Fire CO
2
Pressure Differential
2,000
Natural
9.0% ± 0.2
0.25% lower than high fire CO
2
0.5” to 1.2” wc*
Propane
10.0% ± 0.2
0.25% lower than high fire CO
2
0.5” to 1.2” wc*
3,000
Natural
9.0% ± 0.2
0.25% lower than high fire CO
2
0.5” to 1.2” wc
Propane
10.0% ± 0.2
0.25% lower than high fire CO
2
0.5” to 1.2” wc
4,000
Natural
9.0% ± 0.2
0.25% lower than high fire CO
2
0.5” to 1.2” wc*
Propane
10.0% ± 0.2
0.25% lower than high fire CO
2
0.5” to 1.2” wc*
* - Only check the pressures if there are problems getting the CO
2
and CO values in range.
High fire adjustment
Gas Valve
Low fire adjustment
table 16. Co
2
range and Pressure Differential
figure 32. High and low fire adjustments on the Gas Valve