EngA ENGINEERED AIR base - Typical Combustion Values; Appendix G - Combustion Records

base A
41
IOM74 November 2020 R105
Typical Combustion Values
Review the appliance nameplate for the model number of the heater, the fuel type, and the turndown
(maximum input btuh / minimum input btuh). Values noted are approximate. CO values should be very low.
The maximum acceptable quantity of CO is 200 ppm. Any unit that emits more CO than 200 ppm at any point
in its combustion curve must be corrected.
Contact Service for combustion setup assistance of DJ20 Propane appliances.
DJ(X,E,S) and Large SH with 15:1 turndown
Position
Natural Gas O
2
(%)
Propane O
2
(%)
High Fire (100%)
3.5
–
4.5
4.5
–
5.5
Near High Fire (90%)
3.8
–
4.8
6.0
–
7.0
Medium Fire 2 (55%)
7.0
–
8.5
8.0
–
9.0
Medium Fire 1 (25%)
10.5
–
12.5
11.0
–
13.0
Near Low Fire (10%)
15.0
–
16.0
15.0
–
16.0
Low Fire (6
-
7%)
16.8
–
17.3
16.0
-
17.0
DG-HT Series 20:1 turndown (Natural Gas only)
Position (Fire rate)
Natural Gas O
2
(%)
High Fire (100%)
3.5
–
4.5
Near High Fire (90%)
3.8
–
4.8
Medium Fire 2 (55%)
7.0
–
8.5
Medium Fire 1 (25%)
10.5
–
12.5
Near Low Fire (10%)
15.0
–
16.0
Low Fire (4%)
16.8
–
17.5
DG Series 4:1 turndown (GP Burner – Propane only)
Position (Fire rate)
Propane O
2
(%)
High Fire (100%)
4.5
–
5.5
Near High Fire (90%)
4.8
–
5.8
Medium Fire (55%)
8.0
–
9.5
Low Fire (25%)
10
-
12
Small SH Series (35, 60, 90) 3:1 turndown
Appendix G - Combustion Records
The following documents are to assist factory and field combustion setup. As noted, always ensure there are
increased values set for both fuel pressure and combustion air (either the Vdc or Maxitrol mA output) as the
firing rate increases from low fire to high fire.
Caution:

The combustion setup sequence noted on the combustion records be followed.
Position (Fire rate)
Natural Gas O
2
(%)
High Fire (100%)
3.5
–
4.5
Low Fire (33%)
9.0
–
12.0