37
The optional single-try ignition module will lock out
after failing to light one time. To reset it, press and
release the small, recessed black push button located
inside of the cut-out on the lower right-hand corner
of the ignition module case (see Fig. 28). Turning off
the power to the heater WILL NOT reset the ignition
module.
High Limit (Manual Reset)
The heater is equipped with a manual reset high limit
temperature device. Push the reset button and adjust
the setting to 40 - 50°F above desired operating tem-
perature.
Flow Switch
This dual-purpose control, mounted and wired in
series with the main gas valve, shuts off heater in case
of pump failure or low water flow.
Operating Control
The heater may be equipped with different types of
operating controls. Consult the individual control data
Fig. 29: High Limit (Manual Reset)
Fig. 30: Flow Switch
Ignition Module
When additional heat is needed, the combustion air
blower starts to purge air from the combustion cham-
ber for about 15 seconds. On proof-of-air flow, the
air-
proving switch closes and the igniter is energized. To
ensure safe operation, the gas valve cannot open until
the igniter is verified. The main burner is automatically
lit when the device is powered and pre-purged. The
heater performs its own safety check and opens the
main valve only after the igniter is proven to be capa-
ble of ignition.
Code
Condition
On
System OK;
No faults present
Off
Possible control fault;
Check power
1 Flash
Low air pressure, brief
flashing normal on start-up
2 Flashes
Flame in combustion
chamber; No call for heat
3 Flashes
Ignition lockout
4 Flashes
Low igniter current
5 Flashes
Low 24 VAC, check control
supply voltage
6 Flashes
Internal fault;
Replace module
Fig. 28: Ignition Module
Table O: Ignition Module Diagnostic LED Codes
55. Power is now applied to time delay relay 3 and the
contacts of TD-3 located upstream of the stage 4
connection close after 5 seconds.
56. The stage 4 temperature controller contacts close.
57. Power is sent to gas valve 4.
58. The heater is now operating at full fire.
The standard ignition module will attempt to light three
times before locking out. To reset it, turn off power to
the heater, wait 30 seconds and re-apply power.
Reset but-
ton on 1-try
module
APPROVED
UNCONTROLLED DOCUMENT IF PRINTED
