Raypak 902B, 302B manual Ignition Module

45.The stage 1 LED on the status display board is now illuminated.

46.The coil of relay K-2 is now energized with the N.O. contacts closing downstream of the stage 2 connections.

47.The gas coming through the burners should ignite from the heat of the hot surface igniter and the flame should carry over from one burner to the other burners of stage 1. The remote sensor is now trying to sense the flame. If the flame is not sensed within 4 seconds, the ignition module will shut down gas valve 1 and retry the hot surface igniter. During ignition retry the heater must per- form a 15-second pre-purge and an approximately 30-second igniter warm-up before opening gas valve 1 again. The standard ignition module will attempt ignition a maximum of three times prior to ignition lockout.

48.If the ignition module locks out, a signal will be sent to the Universal Diagnostics Board to indicate an ignition fault.

49.(Models 302B-402B only) 24 VAC is now waiting at pin 3 of the stage 2 connections on the CPW board.

50.(Models 502B-902B only) When power is sent to gas valve 1 it is also sent to time delay relay 1 (TD- 1) which starts a 5-second countdown.

51.(Models 502B-902B only) After the 5-second countdown from TD-1, 24 VAC is waiting at pin 3 of the stage 2 connections on the CPW board.

52.After closure of the stage 2 contacts Gas valve 2 is energized.

53.The stage 2 LED on the status display board is now illuminated.

54.The Heater is now operating at full fire.

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

Fig. 29: Ignition Module

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 automat- ically 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 capable of ignition.

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. 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 igni- tion module case. Turning off the power to the heater WILL NOT reset the ignition module.

Code	Condition
On	System OK;
	No faults present
Off	Possible control fault;
	Check power
1 Flash	Low air pressure, brief flash-
	ing 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 24VAC, check control
	supply voltage
6 Flashes	Internal fault;
	Replace control

Table Q: Ignition Module

Diagnostic LED Codes

36