Weil-McLain 2 Series Manual page 66

series
GV90+
Start-up
(continued)
Integrated boiler control (IBC) sequence of operation — status light indications
Figure 75
STEPS
(After Step 9, the 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
• Block switch contacts
closed
• Blower on
4. Pressure circuit
• Pressure switch contacts
closed
• Ignitor glows
5. Flame proven
• Gas valve open
• Ignitor remains on
6. Limit cycle
• Limit circuit open
• Gas valve closed
• Blower off after postpurge
7. Flame outage *
• Flame out
8. Thermostat satisfied
• Circulator off
• Blower postpurge
9. Low water detection
• LWCO probe detects low
water condition shuts
down boiler until correct
water level is restored.
• Return to Step 1.
* If flame is not proven in
is 30 seconds. Postpurge and prepurge are performed on every cycle. In event of lockout, ignition control will automatically
restore sequence of operation after either:
• 1 hour waiting period.
• Opening and closing of thermostat circuit.
• Removal of 120 VAC power for at least 45 seconds.
66
gas-fired water boiler – boiler manual
2
Call
POWER
for
Heat?
NO
YES
YES
YES
YES
YES
YES
NO
YES/
NO
4 seconds, boiler recycles 2 times to retry for ignition before going into lockout. Recycle igniter timing
TSTAT PRESS
LIMIT
CIRC SWITCH
= ON = OFF
Timing
FLAME LWCO
30 sec
4
30 sec
30 sec
Part number 550-143-010/1021
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sec
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