TABLE 5—PRESSURE REGULATOR SPECIFICATION PRESSURES IN INCHES WC.
Outlet Pressure
Nominal Inlet Nominal Factory Setting Setting Range
Model Type of Gas Pressure Range Step Full Rate Step Full Rate
Standard, Natural 5.0 - 7.0 — 3.5 — 3.0 - 5.0
Slow-opening LP 12.0 - 14.0 — 10.0 — 8.0 - 12.0
Step-opening Natural 5.0 - 7.0 0.9 3.5 — 3.0 - 5.0
LP 12.0 - 14.0 2.2 10.0 — 8.0 - 12.0
TABLE 6—PRESSURE REGULATOR SPECIFICATION PRESSURES IN kPa.
Outlet Pressure
Nominal Inlet Nominal Factory Setting Setting Range
Model Type of Gas Pressure Range Step Full Rate Step Full Rate
Standard, Natural 1.2 - 1.7 — 0.9 — 0.7 - 1.2
Slow-opening LP 2.9 - 3.9 — 2.7 — 2.0 - 3.0
Step-opening Natural 1.2 - 1.7 0.2 0.9 — 0.7 - 1.2
LP 2.9 - 3.9 0.9 2.7 — 2.0 - 3.0
a. Remove the pressure regulator adjustment cap and
screw.
b. Using a screwdriver, turn the inner adjustment screw
clockwise to increase or counterclockwise to
decrease the main burner gas pressure.
c. Always replace the cap screw and tighten firmly to
ensure proper operation.
4. If the desired outlet gas pressure or gas flow rate cannot
be achieved by adjusting the gas control, check the gas control
inlet pressure using a manometer at the inlet pressure tap. If
the inlet pressure is in the normal range (refer to Table 5 or 6),
replace the gas control. Otherwise, take the necessary steps to
provide proper gas pressure to the gas control.
Step-Opening Pressure Regulator
1. The gas control outlet pressure should match the mani-
fold pressure listed on the appliance nameplate.
2. With main burner operating, check the gas control flow
rate using the meter clocking method or check the gas
pressure using a manometer connected to the gas control
outlet pressure tap. Refer to Fig. 2.
3. If necessary, adjust the pressure regulator to match the
appliance rating. Refer to Table 5 or 6 for factory set nominal
outlet pressures and adjustment ranges.
a. Remove the pressure regulator adjustment cap screw.
b. Using a screwdriver, turn the inner adjustment screw
clockwise to increase or counterclockwise to
decrease the main burner gas pressure.
c. Always replace the cap screw and tighten firmly to
ensure proper operation.
4. If desired outlet pressure or flow rate cannot be achieved
by adjusting the gas control, check the inlet pressure using a
manometer at inlet pressure tap or upstream of the gas control.
If the inlet pressure is in the normal range (refer to Table 5 or
6), replace the existing gas control. Otherwise, take the
necessary steps to provide proper gas pressure to the gas
control.
5. Carefully check main burner lightoff at the step pres-
sure. Ensure the main burner lights smoothly and without
flashback to the orifice and that all ports remain lit. Cycle the
main burner several times, allowing at least 30 seconds
between cycles for the regulator to resume the step function.
Repeat after allowing main burner to cool. Readjust the full
rate outlet pressure, if necessary, to improve lightoff charac-
teristics.
VR8305
START-UP AND CHECKOUT
9 68-0109—3
CHECK SAFETY SHUTDOWN PERFORMANCE
WARNING
FIRE OR EXPLOSION HAZARD
CAN CAUSE PROPERTY DAMAGE,
SEVERE INJURY, OR DEATH
Perform the safety shutdown test anytime work is
done on a gas system.
NOTE: Read steps 1-7 below before starting and compare to
the safety shutdown or safety lockout tests recommended
for the direct ignition (DI) module. Where they differ, use
the procedure recommended for the module.
1. Turn off gas supply.
2. Set thermostat or controller above room temperature to
call for heat.
3. Watch for ignition spark or for glow at hot surface
igniter either immediately or following prepurge. See DI
module specifications.
4. Time length of igniter operation. See DI module speci-
fications.
5. After the module locks out, open gas control and ensure
there is no gas flow to main burner.
6. Set thermostat below room temperature and wait one
minute.
7. Operate system through one complete cycle to ensure
all controls operate properly.
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