6
NOTE: Turning the screw clockwise increases the
pressure, turning the screw counter-clockwise
decreases the pressure. To prevent the screw from
backing all the way out from the valve, turn the screw
slowly.
3. Replace and tighten the cap screw or the plastic cap
over the adjustment screw.
Removing the Manometer/Pressure Gauge
After the manifold pressure is properly adjusted, the
Manometer or pressure gauge must be removed from
the gas valve.
1. Turn the thermostat to its lowest setting.
2. Turn OFF the main gas supply to the unit at the manual
shut-off valve, which is located outside of the unit.
3. Turn OFF all of the electrical power supplies to the
unit.
4. Remove the pressure gauge adapter from the gas valve
and replace it with the 1/8” NPT manifold pressure
plug that had been removed earlier. NOTE: Make
sure the plug is tight and not cross-threaded.
5. Turn ON the electrical power to the unit.
6. Turn ON the main gas supply to the unit at the manual
shut-off valve.
thermostat to its lowest setting and wait one minute then
turn the thermostat to a point above room temperature
and the ignitor will try again to ignite the main burners.
This process may have to be repeated several times
before the burners will ignite. After the burners are lit,
check all gas connections for leaks again with the soap
and water solution.
Measuring the Manifold Pressure
The manifold pressure must be measured by installing a
pressure gauge (Manometer, Magnehelic Meter, etc.) to
the outlet end of the gas valve as follows:
1. Shut OFF the gas supply at the manual shutoff valve
located outside of the appliance.
2. Turn off all electrical power to the appliance.
3. Using a 3/16” Allen wrench, remove the manifold
pressure tap plug located on the outlet side of the
gas valve. See Figure 6.
4. Install an 1/8” NPT pipe thread fi tting, that is compatible
with a Manometer or similar pressure gauge.
5. Connect the Manometer or pressure gauge to the
manifold pressure tap.
6. Set the room thermostat to a point above
room temperature to start the furnace.
7. Allow the furnace to operate for 3 minutes and then
check the manifold pressure. Compare the measured
value with the value shown in Table 2 (page 3). If
the manifold pressure is not set to the appropriate
pressure, then it must be adjusted.
Adjusting the Manifold Pressure
NOTE: Adjustments must be made to both LOW & HIGH
fi re settings when converting two-stage gas valves. Refer
to Table 2 for manifold pressures.
1. Single stage gas valve: Remove the cap screw from
the top of the gas valve regulator. See Figure 2 (page
4) for VR8205S2890 or VR8215S1206 models.
2-stage gas valve: For VR8205Q2381 models, remove
the plastic cap covering the adjustment screws (Figure
4 page 4). For VR9205Q1028 models, remove the
cap screw (Figure 5, page 5).
2. Using a screwdriver or allen wrench (where
appropriate), slowly turn the adjustment screw till
the appropriate manifold pressure listed in Table
2 is achieved. See Figure 2 for VR8205S2890 or
VR8215S1206 models. See Figure 4 for VR8205Q2381
models or Figure 5 for VR9205Q1028 models.
COMPLETING THE CONVERSION
WARNING:
Do not alter or remove the original rating plate
from the furnace.
1. Attach the following labels:
• The conversion warning label (P/N 703935) should be
affi xed to the outside of the unit door.
• The conversion information label (P/N 703942) should
be affi xed near the rating plate on the inside of the
control area.
• The gas valve conversion label should be affi xed on the
gas valve.
NOTE: Each label should be prominently visible after
installation.
2. Reinstall the appliance door.
3. Run the appliance through 3 complete cycles to assure
proper operation.
Figure 6. Inlet & Manifold Pressure Tap Locations
IN
ON
OFF
Inlet
Pressure
Ta p
Inlet
Pressure
Ta p
Inlet
Pressure
Ta p
SINGLE STAGE VALVES
Manifold
pressure
Ta p
Manifold
pressure
Ta p
Manifold
pressure
Ta p
Manifold
pressure
Ta p
2-STAGE VALVES
Model VR8215S1206
Inlet
Pressure
Ta p
Model VR8205S2890
Model VR8205Q2381
Model VR9205Q1028
ON/OFF
Switch
ON/OFF
Switch
ON/OFF
Knob
ON/OFF
Switch