Install Instructions

VR8104, VR8204, AND VR8304 INTERMITTENT PILOT COMBINATION GAS CONTROLS
9 69-1225—08
Fig. 9. Proper flame adjustment.
Check and Adjust Gas Input
and Burner Ignition
IMPORTANT
1. Do not exceed input rating stamped on
appliance nameplate, or manufacturer’s
recommended burner orifice pressure for size
orifice(s) used. Make certain primary air supply
to main burner is properly adjusted for complete
combustion. Follow appliance manufacturer
instructions.
2. IF CHECKING GAS INPUT BY CLOCKING GAS
METER: Make certain there is no gas flow
through the meter other than to the appliance
being checked. Other appliances must remain
off with the pilots extinguished (or deduct their
consumption from the meter reading). Convert
flow rate to Btuh as described in form 70-2602,
Gas Controls Handbook, and compare to Btuh
input rating on appliance nameplate.
3. IF CHECKING GAS INPUT WITH MANOMETER:
Make sure the gas control knob is in the OFF
position before removing outlet pressure tap
plug to connect manometer (pressure gauge).
Also move the gas control knob to the OFF
position when removing the gauge and
replacing the plug. Before removing inlet
pressure tap plug, shut off gas supply at the
manual valve in the gas piping to the appliance
or, for LP, at the tank. Also shut off gas supply
before disconnecting manometer and replacing
plug. Repeat Gas Leak Test at plug with main
burner operating.
NOTE: Check the inlet pressure before adjusting the
pressure regulator.
Standard and Slow-Opening
(H, K and M) Models
1. Carefully check the main burner lightoff. Make sure
that the main burner lights smoothly and that all
ports remain lit.
2. Check the full rate manifold pressure listed on the
appliance nameplate. Gas control full rate outlet
pressure should match this rating.
3. With main burner operating, check the control flow
rate using the meter clocking method or check
pressure using a manometer connected to the
outlet pressure tap on the control. See Fig. 6.
4. If necessary, adjust the pressure regulator to
match the appliance rating. See Tables 8A and 8B
for factory-set nominal outlet pressure and
adjustment range.
a. Remove the pressure regulator adjustment cap
screw.
b. Using a screwdriver, turn the inner adjustment
screw (Fig. 6) clockwise to increase or
counterclockwise to decrease the gas
pressure to the burner.
c. Always replace the cap screw and tighten
firmly to prevent gas leakage.
5. If the desired outlet pressure or flow rate cannot
be achieved by adjusting the gas control, check the
gas control inlet pressure using a manometer at
the inlet pressure tap of the gas control. If the inlet
pressure is in the nominal range (see Tables 8A
and 8B), replace the gas control. Otherwise, take
the necessary steps to provide proper gas pressure
to the control.
NOTE: If the burner firing rate is above 150,000 Btuh on
VR8304 models (see Table 1 for VR8304 capac-
ities), it may not be possible to deliver the
desired outlet pressure. This is an application
issue, not a control failure. Take whatever steps
are required to correct the situation.
Step-Opening (P) Models
Step-opening models require that you check and adjust
the full-rate pressure first and then check the step
pressure. The step pressure is not field adjustable.
1. Carefully check the main burner lightoff. Make sure
that the main burner lights smoothly and that all
ports remain lit.
2. Check the full rate manifold pressure listed on the
appliance nameplate. Gas control full rate outlet
pressure should match this rating.
3. With main burner operating, check the gas control
flow rate using the meter clocking method or check
pressure using a manometer connected to the
outlet pressure tap on the gas control. See Fig. 6.
4. If necessary, adjust the pressure regulator to
match the appliance rating. See Tables 8A and 8B
for factory-set nominal outlet pressure and
adjustment range.
a. Remove the pressure regulator adjustment cap
screw.
Using a screwdriver, turn the inner adjustment screw
(Fig. 6) clockwise to increase or
counterclockwise to decrease the gas pressure
to the burner.
b. Always replace the cap screw and tighten
firmly to prevent gas leakage.
5. If the desired outlet pressure or flow rate cannot be
achieved by adjusting the gas control, check the
gas control inlet pressure using a manometer at
the inlet pressure tap of the control. If the inlet
pressure is in the nominal range (see Tables 8A
and 8B), replace the control. Otherwise, take the
necessary steps to provide proper gas pressure to
the control.
6. Carefully check the burner lightoff at step pressure.
Make sure the burner lights smoothly and without
flashback to the orifice. Make sure all ports remain
lit. Cycle the burner several times, allowing at least
60 seconds between cycles for the regulator to
resume the step function. Repeat after allowing the
burner to cool. Readjust the full rate outlet
pressure, if necessary, to improve lightoff
characteristics.
PROPER FLAME
ADJUSTMENT
IGNITER-
SENSOR
M3080A
3/8 TO 1/2 INCH
(10 TO 13 mm)