Weil-McLain CGi 4 Series Manual page 38

CGi
SERIES 4 — GAS-FIRED WATER BOILER —
9a
Operation — sequence
— The circulator continues to operate.
7.
Lower
valves are closed — Inducer operates for 15-second postpurge — Circulator is shut off.
8. Boiler is now in the
9.
Repeat
10.
Return
11. Set thermostat heat anticipator setting as instructed in
Figure 30 Control module sequence of operation — status light indications
STEPS
(following step 7, cycle goes back to step 1.)
1. Standby
• Waiting for call for heat
2. Call for heat
• Circulator on
3. Limit circuit
• Limit controls closed
• Rollout TFE contacts closed
4. Inducer
• Inducer turns on
5. Pressure circuit
• Pressure switch contacts closed
• Prepurge for 10 seconds
6. Flame proven *
• Gas valve open
• Ignitor remains on
• Boiler producing heat
7. Limit cycle
• Limit circuit open
• Gas valve closed
8. Flame outage *
• Flame out
• Boiler recycles
9. Thermostat satisfied
• Circulator off
10. Circulator exercise routine
• Circulator turns on for 30
boiler not operated for 30 days
11. LWCO circuit
• LWCO circuit open
* See Section 9, Items 4b for controls response to failure to prove pilot flame.
Control will lockout under the following conditions:
• Line voltage polarity is reversed
• Stray voltage is sensed on thermostat line
• Flame is sensed when it shouldn't be there
38
room thermostat setting to stop call for heat. Thermostat is satisfied — Pilot and main gas
.
off cycle
steps through several times to verify operation.
1 6
the thermostat to normal setting.
POWER TSTAT
Call for
Heat?
NO
YES
YES
YES
YES
YES
YES
YES
NO
NO
seconds if
YES/NO
Boiler Manual
(continued)
Figure 32
LIMIT
CIRC
= ON
Control will reset after these lockouts if any of the following occur:
• 1 hour waiting period
• Opening and closing of thermostat circuit for 2 to 20 seconds
• Removal of 120 VAC power for 2 to 20 seconds
, page 40.
PURGE FLAME LWCO
= OFF
Part Number 550-142-302/0124
Timing
—
—
—
—
35
sec
15
sec
—
—
15
sec
30
sec
—