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Fault
Code
Displayed
Description Cause
Lockout
type
Remedy
E33 Water Flow Valve
Closed.
The water valve did not
open when attempting to
establish fl ow.
Soft
Check the water valve wire harness.
Change the board.
Change the water valve.
1.
2.
3.
E34 Proportional Valve
(PV) Response
Too Slow.
The closed loop control
of the proportional valve
is not functioning properly
(control error) or the valve
is responding slowly (valve
failure).
Soft
Check the proportional gas valve wire
harness, change the board, change
the gas valve assembly
E35 Repeated Flame
Loss Fault.
Low Gas Inlet Pressure.
Low Water Flow Rate
Soft
Clean or change the water fi lter.
Check the fl ame rod wire harness.
Check line gas pressure. If it is above
5” WC check the fl ame rod and if it
looks dirty, clean it up using isopropyl
alcohol and a clean cloth.
Change the fl ame rod.
Change the board.
1.
2.
3.
4.
5.
E36 Calibration error. Calibration sequence
incomplete because end
of “call-for-heat” during
the calibration time, or
calibration sequence not
initiated because of lack of
“call-for-heat”, or the unit
has been never calibrated
or Calibration is successful
but DIP switch 4 not set to
“normal”.
Soft
Unplug the power cord, check the
DIP switch 4 position and put it in
ON position.
Increase the set point so that a
“call-for-heat” occurs.
Drain the tank in order to lower the
water temperature so that a “call-
for-heat” is generated.
Set DIP switch 4 to OFF position.
Recalibrate the unit.
Change the board.
1.
2.
3.
4.
5.
6.
E37 No Water Flow. The heater could not start
because the water fl ow was
not established. This can be
caused by an air bubble or a
blockage in the heat engine
water passage, a failed fl ow
sensor or a failed circulation
pump. Soft
Check the water inlet on the heat
engine.
Make a water draw during fi rst 60
seconds after putting the unit in ON
mode (to evacuate possible air from
the heat engine water passage).
Check wire harness for pump, water
valve and water fl ow sensor.
Check the pump 120Vac voltage
supply (the pump shall be energized
during the heating mode).
Clean or change the water fi lter.
Change board.
Change pump.
Change water valve.
1.
2.
3.
4.
5.
6.
7.
8.
E99 Board Failure. An internal diagnostic check
on the board has failed.
Soft Change the board.
TABLE 5
Lockout types:
Continuous. Needs “Cycle the Power” or service to restart.
Soft. Will try to automatically recover and restart after 20 minutes.
Auto Reset. Will automatically restart when voltage returns to acceptable parameters.