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Code 031: Incorrect DIP Switch
Se ngs
The system displays this code when an
incorrect DIP switch setting is detected
or DIP switches were changed when
the heater power was on.
1. Turn off the power supply.
2. Remove front cover and locate
the DIP switches at the side of the
computer board.
Refer to "DIP Switch Settings" on
page 25. The correct DIP switch
positions are illustrated in that
section.
For specific DIP switch settings
related to vent length or high-
altitude installations, refer to
the tables that start on page 25.
Additional information is provided
in the Installation Manual/Owner's
Guide.
3. After setting the DIP switches, turn
power to the water heater back on.
Code 051 or 101: Combus on
Air and/or Exhaust Gas
Blockage
Refer to "Error Code: 991," page 22.
Code 111 or 121: Igni on
Failure / Flame Loss
Either the water heater will not fire
after three failed ignition attempts
(code 111) or it lost the flame signal
during a heating cycle and was not
able to establish a flame after three
failed ignition attempts (code 121).
These codes can appear due to a
component in the heater or due to an
external cause, such as no gas supply.
1. Verify that the gas supply pressure is
within specifications when the heater is
16
•
On-Demand Water Heater Service Handbook for X3P Models
in standby, and verify the gas pressure
does not drop below the minimum
specified supply pressure when all
gas appliances are in operation. Also,
verify that the gas line is cleared of
debris.
•
It is possible that there is a faulty
pressure regulator at the gas meter.
•
If a second stage regulator is
installed, verify the following:
that it is sized properly for the
application; that it is installed per
the manufacturer's instruction
(pay close attention if an indoor
vent limiter is installed); the vent
line (if installed) is sized properly.
Note: Some manufacturer's
may recommend that a specific
amount of straight pipe is
installed on the outlet before any
changes in direction. Refer to the
regulator's manufacturer. See
"Checking the Inlet Gas Pressure
and Pressure Drop" on page
30.
2. Check the High Limit Switch and
Overheat Cutoff Fuse (OHCF) as follows:
2.1
Turn off power to the water
heater, then turn it back on.
(Use the switch above the
computer board.) Listen for
the "clunking" noises of the
gas solenoid valves. If you
DO hear them, go directly to
step 3. The water heater may
show error code 711, if this
occurs proceed to the next
step.
2.2
Turn off power to the heater
by disconnec ng the power
cord or external switch.
2.3
Locate the high limit switch
(item 412, p. 74). See also
Figure 21 (p. 40) and Table
8 (p. 41).
2.3.1 Push the bu on in the
middle of it. The switch was
reset if you heard and felt
the bu on click.
2.3.2 Turn the power back on
and test the heater. If the
burner lights, the cause of
the high limit trip must be
determined. Con nue with
the troubleshoo ng process.
Also, be sure to check the
temperature of the incoming
water supply. If the unit is
supplied with pre-heated
water, such as from a solar
system, the incoming water
temperature may be too
high.
2.3.3 If the high limit switch is
opera ng properly and you
don't hear the "clunking"
noises of the gas valves, then
check the overheat cutoff
fuse (OHCF) for con nuity. If
there is no con nuity, or for
instruc ons on how to test
the OHCF for con nuity, refer
to "Checking the Overheat
Cutoff Fuse (OHCF)" on page
32.
3. Check for blockages in venting, such
as bird nests, animals, or trash. A
blockage will cause improper operation
leading reduced capacity and inability
to maintain combustion.
4. Check for a spark inside the burner
chamber between the igniter rods.
The spark may be viewed through
the sight glass located next to the
igniter and flame sensor. A strong
blue spark will remain steady and in
place, while a weak spark will jump
around.
4.1
If no spark or a weak spark is
observed, check the purple
igniter wire connec ons at
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