Weil-McLain Gold CGa Figure 24 Ignition control module sequence of operation status light indications

Boiler Manual

Part Number 550-110-593/1099 37

Figure 24 Ignition control module sequence of operation — status light indications

Follow all procedures given in this manual and operating

instructions when operating the boiler. Failure to do so

could result in severe personal injury, death or

substantial property damage.

Operation — spark-ignited pilot boilers9a

1. Standby: With no call for heat, the vent damper and

circulator are deenergized. No gas flows to pilot or main

gas valve.

2. Call for heat (thermostat circuit closes):

a. Vent damper and circulator energized if pilot status

acceptable. Vent damper drives open. When vent

damper end switch makes circuit, ignition control

begins pilot ignition attempt.

b. Ignition control checks for false flame signal: If

ignition control senses pilot signal when no pilot

gas should be present, control will lockout,

requiring reset procedure as given inFigure 24.

3. Pilot ignition: Control module sparks the pilot and

opens pilot valve in main gas valve.

a. If pilot does light and control module senses flame

current, spark generator is turned off and main

valve opens.

b. If pilot does not light within 15 seconds, pilot valve

is closed and spark generator is turned off. Control

module waits 5 minutes, then attempts to ignite

pilot again. This cycle will continue indefinitely if

pilot ignition control does not sense pilot flame.

4. Main burner operation:

a. Control module monitors pilot flame current. If

signal is lost, main valve closes, spark generator

activates and sequence returns to step 4.

b. If power is interrupted, control system shuts off

pilot and main gas valves and restarts at step 1 when

power is restored.

c. In the event the limit control shuts down the boiler

— The control module closes the main gas valve,

but keeps the circulator operating and the vent

damper open.

5. Thermostat satisfied (thermostat circuit opens) —

Pilot and main gas valves are closed — Vent damper is

deenergized, and cycles to closed position. Circulator

is shut off.

6. Boiler is now in the standby mode.

7. Thermostat anticipator setting: Set thermostat heat

anticipator as instructed in Figure 25b, page 39.

= "OFF"

or = "ON"

(Followingstep 7, cycle goes back to step 1.)

59340

1. Standby

Waiting for call for heat·

2. Call for heat

· Circulator on

3. Limit circuit

· Limit controls closed

4. Damper circuit

· Damper proven open

5. Pilot flame proven *

· Gas valve open

· Pilot remains on

· Boiler producing heat

6. Limit cycle

· Limit circuit open

· Gas valve closed

7. Flame outage *

· Flame out

· Boiler recycles

8. Thermostat satisfied

· Circulator off

9. Circulator exercise routine

· Circulator turns on for 30 seconds

ifboiler not operated for 30 days

*Ifpilot flame is not proven in 15 seconds, control module will flash the FLAME light, but will continue indefinitely with attempts to light the pilot burner.

The control module will not lockout on a failure to establish flame.It will lockout if line voltage polarity is reversed,str ay voltage is sensed on thermostat

line,or if flame is sensed when it shouldn’t be there.

The boiler will reset after these lockouts ifany of the following occurs:

• 1 hour waiting period • Opening and closing ofthermostat circuit • Removal of 120 VAC power for at least 45 seconds.

POWER TSTAT

CIRC

LIMIT DAMPER FLAME

Call for

heat?

Timing

YES

—

15 sec

—

15 sec

30 sec

Steps