CGi Manual

Part Number 550-142-302/0520
CGi
SERIES 4 — GAS-FIRED WATER BOILER — Boiler Manual
38
Operation — sequence (continued)
9a
— The circulator continues to operate.
7.
Lower room thermostat setting to stop call for heat. Thermostat is satisfied — Pilot and main gas valves are
closed — Inducer operates for 15-second postpurge — Circulator is shut off.
8. Boiler is now in the off cycle.
9. Repeat steps 1 through 6 several times to verify operation.
10.
Return the thermostat to normal setting.
11. Set thermostat heat anticipator setting as instructed in Figure 32, page 40.
Figure 30 
STEPS

Call for
Heat?
POWER TSTAT
CIRC
LIMIT PURGE FLAME LWCO
Timing
1. Standby
• Waiting for call for heat
NO —
2. Call for heat
• Circulator on
YES —
3. Limit circuit
• Limit controls closed
• Rollout TFE contacts closed
YES
—
4. Inducer
• Inducer turns on
YES
—
5. Pressure circuit
• Pressure switch contacts closed
• Prepurge for 10 seconds
YES
35
sec
6. Flame proven *
• Gas valve open
• Ignitor remains on
• Boiler producing heat
YES
15
sec
7. Limit cycle
• Limit circuit open
• Gas valve closed
YES
—
8. Flame outage *
• Flame out
• Boiler recycles
YES
—
9. Thermostat satisfied
• Circulator off
NO
15
sec
10. Circulator exercise routine
• Circulator turns on for 30 seconds if
boiler not operated for 30 days
NO
30
sec
11. LWCO circuit
• LWCO circuit open
YES/NO —
= ON = OFF
 

 
 



• 
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