Adjust Gas Valve
How do I adjust the pressure on the 2 stage gas valves?
Adjusting the 2 Stage Gas Valve
Tools needed to adjust a 2 stage valve include:
1. A Small flat Blade Screwdriver
2. A 3/32” Allan Wrench
3. A manometer capable of accurately reading Inches of Water Column
4. A short piece of 5/16” I.D. hose
5. A 5/16” to ¼” hose reducer fitting (Most manometers have ¼” hose connections)
6. A length of 1/4” I.D. Hose
If desired kit# F0092-100300S1 can be ordered from RPD and will include:
1. A 3/32” Allan Wrench
2. A 5/16” to ¼” hose reducer fitting
3. A short Piece of 5/16” I.D. Hose
Before adjusting the manifold pressure, first make sure your Gas Inlet Pressure is within the tolerances stated in the Installation Instructions. Static pressure, (Without the furnace running), is not accurate. Inlet pressure should be checked with the furnace operating at high fire. If there are other gas appliances, (2nd furnace, pool heater, water heater, etc.), it is a good idea to check the inlet pressure while all are burning gas. This will ensure you have enough volume of gas to supply the furnace when all are burning.
You will need to loosen, (Do NOT Remove) the inlet pressure tap screw using a 3/32” Allan wrench. One revolution is enough. Slide the 5/16” I.D. hose over the inlet pressure tap, and connect the hose to a manometer. After inlet Pressure is deemed acceptable, turn off the gas, remove the hose, and tighten the 3/32” Allan screw.
To read your manifold pressure you will need to loosen, (Do NOT Remove) the manifold pressure tap screw using a 3/32” Allan wrench. Slide the 5/16” I.D. hose over the manifold pressure tap, and connect the hose to a manometer.
Remove the brass regulator cap so that you can access the plastic manifold screw. Adjust clockwise to increase manifold pressure, or counter clockwise to decrease manifold pressure. Repeat the process for low fire using the low fire adjustment screw. After manifold pressure is deemed acceptable, turn off the gas, remove the hose, tighten the 3/32” Allan screw, and replace the brass regulator caps.
Make sure the Manifold pressure is within tolerances.
Natural Gas: 3.5” (±.3) w.c. for High Fire, 1.8” (±.1) w.c. for low fire.
L.P.: 10.0” (±.5) w.c. for High Fire, 4.9” (±.2) w.c. for low fire.
NOTE: You can easily strip out the plastic adjustment screw head if your screwdriver is too small.
NOTE: If you completely bottom out the plastic screw, you may not be able to back it out.
