Reznor VR Unit Installation Manual - Manual (Page 24)

Form I-VR, P/N 205202 R13, Page 23
But if adjustment is required, set pressure to correct settings by turning the
regulator screw IN (clockwise) to increase pressure. Turn regulator screw OUT
(counterclockwise) to decrease pressure.
Remove manometer, replace the cap, and check for leak at pressure tap.
CAUTION: DO NOT bottom out the gas valve regulator adjusting
screw. This can result in unregulated manifold pressure causing
excess overfire and heat exchanger failure.
1. Determine the required valve outlet pressure for the elevation where the
heater will be operating. If unsure of the elevation, contact the local gas
supplier.
Instructions for High
Altitude Derate
3. Turn the knob or switch on the valve to “ON”. Remove the cap from the
pressure adjusting screw and adjust the gas train pressure to the pressure
selected from the table above. Adjust pressure by turning the regulator
screw IN (clockwise) to increase pressure or OUT (counterclockwise) to
decrease pressure.
4. Turn up the thermostat. Cycle the burner once or twice to properly seat the
adjustment spring in the valve.
Re-check the pressure(s). When the outlet pressure is right for the installa-
tion, remove the manometer and replace the cap.
Check for leak at the pressure tap fitting.
5. With the heater operating, determine that the inlet pressure to the valve for
natural gas is between 4.5” and 14” w.c. for Sizes 50-150 and between 6”
Derate is by Valve
Outlet Pressure
Adjustment for High
Altitude Operation
This adjustment can
only be done after the
heater is in operation.
It is included in the
startup procedures.
NOTE: Sizes 50-175 - If
elevation is above 6000
ft (1830M), a high altitude
pressure switch should
have been installed; see
Paragraph 6.1.
FIGURE 24 - Gas
Valve (two styles)
showing Outlet
Pressure Tap and
Adjustment Locations
1/8” Output
Pressure Tap
Inlet
Pressure
Tap
Output
Adjustment Screw
Manifold Pressure Settings by Altitude for the United States
Altitude Natural Gas (“ w.c.) Propane (“ w.c.)
Feet Meters
50, 75, 100, 125,
150
175 & 200
50, 75, 100, 125, 150,
175, 200
0 - 2000 0 - 610 3.5 5.0 10.0
2001 - 3000 611 - 915 2.7 3.9 7.7
3001 - 4000 916 - 1220 2.5 3.5 7.1
4001 - 5000 1221 - 1525 2.2 3.2 6.4
5001 - 6000 1526 - 1830 2.0 2.9 5.8
6001 - 7000 1831 - 2135 1.8 2.6 5.2
7001 - 8000 2136 - 2440 1.6 2.3 4.6
8001 - 9000 2441 - 2745 1.4 2.0 4.1
9001 - 10000 2746 - 3051 1.3 1.8 3.6
Manifold Pressure Settings by Altitude for Canada
Altitude Natural Gas (“ w.c.) Propane (“ w.c.)
Feet Meters
50, 75, 100, 125,
150
175 & 200
50, 75, 100, 125, 150,
175, 200
0 - 2000 0 - 610 3.5 5.0 10.0
2001 - 4500 611 - 1373 2.8 4.1 8.1
2. Locate the 1/8” output pressure tap on the valve (See FIGURE 24). Turn
the knob or switch on the valve to “OFF”. Connect a manometer to the 1/8”
pipe outlet pressure tap in the valve. Use a water column manometer that
is readable to the nearest tenth of an inch.
1/8” Outlet
Pressure
Tap
Inlet
Pressure
Tap
Adjust Outlet
Pressure