Checking Manifold Pressure - andrews 24/39 Installation And Service Manual

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 heater gas valve. Line
pressure should be:
Nat.=Min. 5.5"W.C.: Max. 14.0"W.C.
LP=Min. 11.0"W.C.; Max. 14.0"W.C.
Is gas pressure within proper
specification?
Yes
Check manifold pressure. Refer to water heater rating label for specified manifold
pressure. If the manifold pressure is not within 0.3" w.c. of the specified pressure,
then remove the regulator cap from the gas valve and turn plastic screw
clockwise to increase pressure and 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.?
Yes
Check venting conditions, clogged
vent, down drafts or negative
building pressure Is vent system
okay?
Yes
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.
Yes
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 build-up. Clean burner as
necessary. (see Main Burner and
Pilot Removal and Inspection)
Check tank flues for blockage or
debris build-up causing restriction.
(see Flue Baffle Removal,
Inspection)
Issue 2 14/07/16
Determine cause of incorrect gas
No
pressure and correct. Contact your
gas supplier.
No
Correct improper venting condition.
Refer to Installation Instructions
Provide proper combustion air to
No
water heater. Refer to Installation
Instructions

10.7.2 Checking manifold pressure

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.
No
Appendix
Replace gas valve.
10
99