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Problems are stated in upper case, bold face. Most common
causes for the problems follow in order of likelihood. The
suggested solutions require that the cover be taken off. To
do this, remove incandescent particle tray, pull off the
temperature adjustment knob and unscrew and remove the
plastic collar. Pull main cover out toward you and lift up and
out.
NO SPARK AT THE PILOT
1. On/Off switch is not ”On” (Position ).
The On/Off switch is located behind the flipdown cover
plate on the front panel strip. See fig. 9.
2. Cross over in water lines
To confirm there is no cross-over in the plumbing, shut off
the cold water supply to the 425 HN and open all hot water
faucets. There should not be any water flowing at any faucets.
Water running is a sign of a plumbing cross-over. Consult
your service person.
3. Water flow is not sufficient to activate heater.
Water flow rate at faucet is below minimum flow needed to
activate heater. When temperature adjustment knob is turned
all the way clockwise, the model 425 HN requires 1/2 gallon
per minute flow to activate the heater. As a reference, this
is a flow which would fill a quart jar in 30 seconds. If the
temperature adjustment knob is turned fully
counterclockwise, a flow rate of 1.1 gallons/minute is required
to activate the heater.
The red LED light (located behind the coverplate on the
front panel) flashes when the water flow is not enough.
4. Water inlet filter is clogged
Water flow is restricted, preventing needed flow to activate
heater. Clean water inlet filter screen.
5. Cold incoming water connection made to wrong side
of heater
Make sure cold water inlet connection is on the right side of
heater when you are facing heater.
6. Water valve parts may be dirty or components damaged
First check that venturi is free of dirt particles. Water valve
and component parts must be totally free of dirt. In hard
water areas, mineral deposits can eventually (3-5 years in
hard water areas) corrode the water valve parts to a point
where they will need replacing. Any sign of moisture or
corrosion at the joint of the water valve and the gas valve is
a sign that the water valve components need to be serviced
immediately.
7. Poor circuit connections at the ECO (overheat sensor)
or the flue gas safety device
Ignition sparker will not operate if the electrical circuit is
interrupted. Check that the connections to the ECO and
Flue Gas Safety Device are secure and tighten if necessary.
If the 425 HN is Powervented, check spill switch reset
SPARK APPEARS AT PILOT WHEN HOT WATER TAP
TURNED ON, BUT PILOT AND BURNERS WILL NOT IGNITE
1. Air in the Gas Line
Normally this is a problem at time of initial installation, after
the pipes have been worked on, or after a gas supply line
has been allowed to empty. Bleed the air trapped in the gas
line by turning the hot water faucet on and off until the air
has been cleared from the line.
2. No gas to the 425 HN
A. Gas cock on gas line may not be open
B. Gas regulator may be shut or damaged. Replace or unlock
the regulator. Note: The regulator furnished with the heater
is exclusively designed for low gas pressure. Excessive
pressure will lock it up. Locking usually happens when using
propane gas if the gas pressure between the gas tank and
the water heater’s gas regulator has not been reduced. See
Page 2 for recommended correct gas pressure. To unlock a
regulator, consult your service person.
3. Pilot orifice or gas valve is dirty
Clogging of the pilot burner can be caused by dust in the
air or dirt in the gas. The pilot orifice or gas filter may need
to be cleaned or replaced.
4. Pilot electrovalve switch may need to be replaced (See
Fig 13).
Measure milivoltage at pilot electrovalve (see Fig. 13).
5. Electronic Control Box may need to be replaced (See
Fig 13).
Check wire connections and test operation of electronic
control box (see Fig. 13).