ULTRA HIGH EFFICIENCY POWER VENT/POWER DIRECT VENT - SERVICE MANUAL
GAS PRESSURES (CONT)
CHECKING GAS PRESSURES (CONT)
Typical manifold and supply gas pressures during:
1Standby Mode
2
3Heating Mode
1BLOWER OFF / GAS VALVE OFF Manifold 0.00” W.C. Supply +9.70” W.C.
Manifold |
| Supply |
Gas |
| Gas |
2 BLOWER ON / GAS VALVE OFF
Manifold
5Open the supply gas shut off valve - restore power - start a heating cycle.
6The rise in manifold pressure and corresponding drop in supply gas pressure confirms the water heater’s gas valve is opening and gas is flowing to the burner.
7Record the supply and manifold gas pressures with the water heater firing.
8Supply gas pressure should not drop below minimum given in Table 2 below.
9Manifold gas pressure should be within the range shown in Table 2 below.
10Look through the burner view port (page 11) burner flame should be blue.
11Shut off power and gas supply - disconnect manometers - close test port needle valves.
12Restore power and gas supply. Check for gas
3 BLOWER ON / GAS VALVE ON
Manifold +0.05” W.C. Supply +7.04” W.C.
Manifold
Gas
Supply
Gas
Manifold Gas
Supply Gas
Service Notes - Gas Pressure Adjustment
Manifold gas pressure is factory set and should not be adjusted in the field. If manifold gas pressure differs greatly from the pressures in Table 2 consider the calibration of the manometer being used - try a different manometer. Call the technical support phone number on the water heater label for further assistance if pressures are considerably different.
Table 2 - Gas Pressures
FUEL TYPE | †MINIMUM SUPPLY | MAXIMUM SUPPLY | MANIFOLD | |
Natural Gas | 3.5” W.C. (0.87 kPa) | 14.0” W.C. (3.48 kPa) | 0.00” to +0.05” W.C. | |
(0.00 to +0.012 kPa) | ||||
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Propane Gas | 8.0” W.C. (1.99 kPa) | 14.0” W.C. (3.48 kPa) | 0.00” to +0.05” W.C. | |
(0.00 to +0.012 kPa) | ||||
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†. Minimum supply gas pressures must be maintained under both load and no load conditions.
Technical Literature Department | 17 of 52 | Ashland City, TN © 2008 |
Servicing should only be performed by a Qualified Service Agent |
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