SERVICE PROCEDURE D24-III
Main Burner Operation Testing
DANGER
120 volt exposure. To avoid personal injury, use caution while performing this procedure.
CAUTION |
Be Careful When Making Voltage |
Measurements or Jumping Terminals |
Not to Damage or Deform Connectors or |
Connector Pins. |
Condition:
Main burner short cycles.
Control Display may show error
code “63, 57, or 4” and be in
“Soft Lockout” state.
Check gas inlet pressure to the water |
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heater gas valve. |
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Line pressure should be: |
| Determine cause of incorrect gas |
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Nat. = Min. 5.5" W.C.: Max. 14.0" W.C. |
| pressure and correct. Contact |
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N |
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LP = Min. 11.0" W.C.; Max. 14.0" W.C. | your gas supplier. |
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Is gas pressure within proper |
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specification? (see photo below) |
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| Y |
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Check manifold pressure. See photo on lower right section of page for |
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manifold pressure tap location. Refer to water heater rating label for |
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specified manifold pressure. If the manifold pressure is not within 0.3" | N |
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w.c. of the specified pressure, then remove the regulator cap from the |
| Replace Gas Valve. | ||||
gas valve and turn plastic screw clockwise to increase pressure and |
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counterclockwise to decrease pressure. Be sure inlet gas pressure is at least 1" w.c. above the manifold pressure. Replace regulator screw and pressure tap cap when finished. Is manifold pressure O.K.?
Y
Check venting conditions, clogged vent,
down drafts or negative building
pressure
Is vent system okay?
Y
Is there sufficient combustion air being supplied to the water heater? Are there combustion air openings or supply pipes to the room? Open access door to the utility room to see if problem is corrected.
Y
Check for unstable pilot flame or oxidation of the flame rod on pilot causing weak pilot signal. Make sure pilot shield is in place and does not touch pilot flame sensor.
(See Pilot Inspection section)
Check burner tubes for scale or debris
(see Main Burner and Pilot Removal and
Inspection)
Check tank flues for blockage or debris
build-up causing restriction.
(see Flue Baffle Removal, Inspection)
N Correct improper venting 
condition. Refer to
Installation Instructions
Line gas | Gas Valve pressure |
pressure port | regulator cap (adjustment |
| screw accessible by |
| removing cap screw) |
| Provide proper |
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N | combustion air to water | 16 |
| heater. Refer to |
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Installation Instructions
Connect hose barb to manifold pressure port shown above, then connect monometer to measure gas manifold pressure.
Manifold Pressure Port with hose
barb inserted for measuring
pressure
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