25
Fig. 36 — Spark Adjustment
GAS VALVE
All unit sizes are equipped with 2-stage gas valves. See Fig. 37 for
locations of adjustment screws and features on the gas valves.
Fig. 37 — Gas Valve
To adjust gas valve pressure settings:
Check Unit Operation and Make Necessary Adjustments
NOTE: Gas supply pressure at gas valve inlet must be within
specified ranges for fuel type and unit size. (See Tables 5-8.)
1. Shut off electrical power supplies to unit and install lockout
tag.
2. Shut off manual gas shut off valve located on gas supply line.
3. Remove manifold pressure tap plug from manifold and con
-
nect pressure gage or manometer. (See Fig. 34.)
4. Turn on electrical supply.
5. Open manual shut off valve, then turn on unit main gas valve.
6. Set room thermostat to call for heat. Verify high-stage heat
operation before attempting to adjust manifold pressure.
7. When main burners ignite, check all fittings, manifold, and
orifices for leaks.
8. Adjust high-stage pressure to specified setting by turning the
plastic adjustment screw clockwise to increase pressure,
counter-clockwise to decrease pressure.
LOW REGULATOR COVER SCREW
(TWO STAGE ONLY)
REGULATOR ADJUST SCREW
REGULATOR SPRING
PILOT COVER SCREW
PILOT GASKET
PILOT ADJUST SCREW
SINGLE STAGE AND TWO STAGE
HIGH REGULATOR COVER SCREW
REGULATOR ADJUST SCREW
REGULATOR SPRING
OUTLET PRESSURE TAP
IMPORTANT: Leak check (using a mixture of soapy water
or leak detection fluid) all gas connections including the
main service connection, gas valve, gas spuds, and manifold
pipe plug. All leaks must be repaired before firing unit.