16
P a g e
Troubleshooting
Whenever the user opens a hot water faucet,
the water activates the “Flow Switch”, which
provides a thermostatic request to the Circuit
Board for Ignition. Upon the request the Circuit
Board performs the following tasks:
1.
Microprocessor reset and self-check
2
. Verification that no flame is present
3.
Verification that the Sail Switch is open
4.
Turn on the Blower
5.
Upon detection of combustion air flow,
starts the ignition routine by opening the
gas valve and supplying the first sparking
sequence.
Normally the ignition trial is successful and
the user will start receiving warm water at the
faucet.
The Control Board detects the conditions
that could result in a hazardous situation
and either prevents the Gas ignition to occur
or immediately shuts down the flame by
interrupting the gas flow to the burner. The
failures detected by the Control Board are:
Failure to light
If the burner fails to light, or if flame is not
detected during the first ignition attempt, the
gas valve is de-energized and the control goes
through an inter-purge delay before ignition
is attempted again. The control will attempt
two additional ignition sequences before going
into ‘LOCKOUT’ after which the valve relay
will remain de-energized and the blower will
turn off after a five minute delay. (Lockout
Condition)
Recovery from ‘lockout’ requires a manual
reset by either resetting the thermostatic
demand (turning off the water flow) or turning
off the power for a period of 5 seconds and
then opening the HOT Water Faucet.
Flame failure
If the established flame signal is lost while the
burner is operating, the control will respond
within 0.8 seconds, the gas valve is de-
energized and a new inter-purge and
ignition routine will begin. If the burner does
not light, the control will de-energize the gas
valve and will make two more attempts to
relight the burner. If the burner does not relight
after the three trials the control will
go into LOCKOUT as noted above in “Failure
to light”. If flame is re-established, normal
operation resumes.
Combustion airflow problems
If the airflow signal is lost, or the hi-limit switch
(See Notice Page 11) opens during operation,
the gas valve is immediately
de-energized and the blower stays on. If the
switch closes again, a normal ignition sequence
will resume. If not, and if this condition persists
for more than five minutes, the control will enter
lockout with the blower off.
Diagnostics feature
If the unit stops operating normally, please
check the LED indicator on the user panel. If the
LED is on or blinking, the blinking pattern will
notify you of the fault detected by the Control
Board as follows:
• Steady On - Internal Control Fault
• 1 Flash - Air Fault
• 2 Flashes - Flame Detection Error
• 3 Flashes – Lockout
• 4 Intentionally ‘NA’ – Reserved for
Future Diagnostics
• 5 Flashes - Low voltage
The blinking LED pattern will be repeated at
intervals of three (3) seconds.