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Slow-opening and Step-opening Pressure Regulators
1. Check the full rate manifold pressure listed on the
appliance nameplate. Gas control full rate outlet pressure
should match this rating.
2. With main burner operating, check gas control flow
rate using the meter clocking method or pressure using a
manometer connected to the outlet pressure tap on the gas
control. See Fig. 4.
3. If necessary, adjust pressure regulator to match ap-
pliance rating. See Table 5 or 5A for factory set nominal
outlet pressure and adjustment range.
a. Remove pressure regulator adjustment cap screw.
b. Using a screwdriver, turn inner adjustment screw
clockwise
to decrease gas pressure to burner.
TABLE 5—PRESSURE REGULATOR SPECIFICATION PRESSURES IN in. wc.
Model Type
Standard, slow
Step
TABLE 5A—PRESSURE REGULATOR SPECIFICATION PRESSURES IN kPa.
Model Type
Standard, slow
Step
CHECK SAFETY LOCKOUT (SLOW-OPENING
CONTROLS ONLY)
1. With the system power off and the thermostat set to
call for heat, manually shut off the gas supply.
2. Energize ignitor control and start timing safety lock-
out time. When spark ignition terminates, stop timing.
When using the VR8205H step-opening control, the
specified ignitor control safety lockout time must exceed
8.5 seconds for system to function properly.
3. After spark cutoff, manually reopen gas control knob.
No gas should flow to the main burner.
4. Reset system by adjusting thermostat below room
temperature, waiting 30 seconds, and moving thermostat
setting up to call for heat. Normal ignition should occur.
69-0329—4
to increase or counterclockwise
Type
Nominal Inlet
of Gas
Pressure Range
Natural
5.0-7.0
LP
12.0-14.0
Natural
5.0-7.0
LP
12.0-14.0
Type
Nominal Inlet
of Gas
Pressure Range
Natural
1.2-1.7
LP
2.9-3.9
Natural
1.2-1.7
LP
2.9-3.9
c. Always replace cap screw and tighten firmly to
prevent gas leakage.
4. If desired outlet pressure or flow rate cannot be
achieved by adjusting the gas control, check gas control
inlet pressure using a manometer at the gas control inlet
pressure tap. If inlet pressure is in the normal range (see
Table 5 or 5A), replace gas control. Otherwise, take the
necessary steps to provide proper gas pressure to the con-
trol.
5. STEP-OPENING PRESSURE REGULATORS
ONLY. Carefully check burner lightoff at step pressure.
Make sure burner lights smoothly and without flashback to
orifice. Make sure all ports remain lit. Cycle burner several
times, allowing at least 30 seconds between cycles for
regulator to resume step function. Repeat after allowing
burner to cool. Readjust full rate outlet pressure if neces-
sary to improve lightoff characteristics.
Factory Set Nominal
Outlet Pressure
Step
Full Rate
—
3.5
—
10.0
0.9
3.5
2.2
10.0
Factory Set Nominal
Outlet Pressure
Step
Full Rate
—
0.9
—
2.5
0.2
0.9
0.5
2.5
CHECK SAFETY SHUTDOWN PERFORMANCE
!
WARNING
FIRE OR EXPLOSION HAZARD,
CAN CAUSE PROPERTY DAMAGE,
SEVERE INJURY OR DEATH.
Perform the safety shutdown test any time work is
done on a gas system.
NOTE: Read steps 1-7 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.
6
Setting Range
Step
Full Rate
—
3-5
—
8-12
None
3-5
None
8-12
Setting Range
Step
Full Rate
—
0.7-1.2
—
2-3
None
0.7-1.2
None
2-3
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