INLET PRESSURE TAP
ON/OFF SWITCH
FFO
ON
BURNER
ENCLOSURE
REFERENCE
PRESSURE TAP MANIFOLD
PRESSURE
TAP
A97386
Fig. 56—Redundant Automatic Gas Valve
BURNER
ORIFICE
A93059
Fig. 57—Burner Orifice
m.Move setup switch
EXAMPLE:
Btu heating input = Btu/cu ft X cu ft/hr Heating value of gas = 975 Btu/cu ft
Time for 1 revolution of
Btu heating input = 103 X 975 = 100,425 Btuh. In this example, the orifice size and manifold pressure adjustment is within ±2 percent of the furnace input rate.
NOTE: Measured gas inputs (high heat and low heat) must be within ±2 percent of that stated on furnace rating plate when installed at sea level or derated per that stated above when installed at higher altitudes.
n.Remove jumper across R, W/W1, and W2 thermostat connections to terminate call for heat.
B. Set Temperature Rise
CAUTION: Temperature rise must be within limits specified on unit rating plate. Recommended operation is at midpoint of rise or above. Failure to follow this caution may result in overheating the heat exchangers or condensing flue gases in heat exchanger areas not designed for condensate.