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Gas Manifold Pressure Measurement And Adjustment; Gas Input Rate Measurement-Natural Gas Only - Whirlpool WGFD28 Installation Instructions Manual

80% 2-stage variable speed gas furnace gold models
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Inlet Gas Supply Pressure
Natural Gas
Minimum: 5.0" W.C. Maximum: 10.0" W.C.
Propane Gas
Minimum: 11.0" W.C. Maximum: 13.0" W.C.
If the supply pressure differs from chart, make the necessary
adjustments to the pressure regulator, gas piping size, etc., and/
or consult with local gas utility.
6. Turn off the gas supply to the furnace at the manual shutoff
valve.
7. Disconnect the manometer.
8. Reinstall plug before turning on gas supply to furnace.
9. Turn off any unnecessary gas appliances that were turned on
in Step 4.
Measuring Inlet Gas Pressure—Alternate Method
A
B
G
A. Gas supply line
B. Gas shutoff valve
C. Gas supply line to furnace
D. Open to atmosphere
Gas Manifold Pressure Measurement and
Adjustment
CAUTION
To prevent unreliable operation or equipment damage,
the gas manifold pressure must be as specified on the
unit rating plate. Only minor adjustments should be made
by adjusting the gas control valve pressure regulator.
Only small variations in gas pressure should be made by
adjusting the gas control valve pressure regulator. The manifold
pressure must be measured with the burners operating. To
measure and adjust the manifold pressure, use the following
procedure.
1. Turn off the gas supply to furnace at the manual gas shutoff
valve external to the furnace.
2. Turn off electrical power to the system.
3. Outlet pressure tap connections:
Honeywell VR9205 valve: Remove the outlet pressure
boss plug. Install an ¹⁄₈" NPT hose barb fitting into the
outlet pressure tap.
White-Rodgers 36G54 valve: Turn outlet pressure test
screw (inlet/outlet pressure boss) one turn
counterclockwise (not more than one turn).
C
D
F
E
E. Manometer
F. Manometer hose
G. Dripleg cap with fitting
4. Attach a hose and manometer to the outlet pressure barb
fitting (Honeywell valve) or outlet pressure boss
(White-Rodgers valve).
5. Turn on the gas supply.
6. Turn on power and close thermostat R and W1 contacts to
provide a call for low-stage heat.
7. Measure the gas manifold pressure with burners firing.
8. Adjust manifold pressure using the Manifold Gas Pressure
chart shown below.
9. Remove the regulator cover screw from the low (LO) outlet
pressure regulator adjust tower.
10. Turn the screw clockwise to increase pressure or
counterclockwise to decrease pressure.
11. Replace regulator cover screw.
12. Close thermostat R and W2 contacts to provide a call for
high-stage heat.
13. Remove the regulator cover screw from the high (HI) outlet
pressure regulator adjust tower.
14. Turn the screw clockwise to increase pressure or
counterclockwise to decrease pressure.
15. Replace the regulator cover screw.
16. Turn off electrical power and gas supply to the system.
17. Remove the manometer hose from the hose barb fitting or
outlet pressure boss.
18. Replace the outlet pressure tap:
Honeywell VR9205 valve: Remove the ¹⁄₈" NPT hose barb
fitting from the outlet pressure tap. Replace the outlet
pressure boss plug and seal with a high quality thread
sealer.
White-Rodgers 36G54 valve: Turn the outlet pressure test
screw in to seal pressure port (clockwise, 7 in.-lb
minimum).
19. Turn on electrical power and gas supply to the system.
20. Close the thermostat contacts R and W1/W2 to energize the
valve.
21. Using a leak detection solution or soap suds, check for leaks
at the outlet pressure boss plug (Honeywell valve) or screw
(White-Rodgers valve). Bubbles forming indicate a leak.
IMPORTANT: If a leak is detected, turn off gas immediately
and repair all leaks.
NOTE: For gas-to-gas conversion, consult your dealer for
appropriate conversion.
Manifold Gas Pressure
Gas
Natural
Low Stage
High Stage
Propane
Low Stage
High Stage
Gas Input Rate Measurement—Natural Gas Only
The gas input rate to the furnace must never be greater than that
specified on the unit rating plate. To measure Natural gas input
using the gas meter, use the following procedure.
1. Turn off the gas supply to all other gas-burning appliances
except the furnace.
2. While the furnace is operating, time and record one complete
revolution of the smallest gas meter dial.
3. Calculate the number of seconds per cubic foot (sec/ft
gas being delivered to the furnace. If the dial is a one cubic
Range
Nominal
1.6" to 2.2" W.C.
1.9" W.C.
3.2" to 3.8" W.C.
3.5" W.C.
5.7" to 6.3" W.C.
6.0" W.C.
9.7" to 10.3" W.C. 10.0" W.C.
3
) of
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