Weil-McLain GV90+ User Manual

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Part number 550-142-054/1211

GV90+ gas-fired water boiler — Boiler Manual

Figure 75 Integrated boiler control (IBC) sequence of operation — status light indications

STEPS

(After Step 8, the cycle goes back to Step 1)

Call for

Heat?

POWER TSTAT

CIRC

LIMIT PRESS

SWITCH

FLAME

Timing

1. Standby

• Waiting for call for heat

—

2. Call for heat

• Circulator on

YES —

3. Limit circuit

• Limit controls closed

• Block switch contacts closed

• Blower on

YES —

4. Pressure circuit

• Pressure switch contacts closed

• Ignitor glows

YES

30 sec

5. Flame proven

• Gas valve open

• Ignitor remains on

YES

6 sec

6. Limit cycle

• Limit circuit open

• Gas valve closed

• Blower off after postpurge

YES

30 sec

7. Flame outage *

• Flame out

YES —

8. Thermostat satised

• Circulator off

• Blower postpurge

• Return to Step 1

NO 30 sec

= ON

= OFF

* If ﬂame is not proven in 4 seconds, boiler recycles 2 times to retry for ignition before going into lockout. Recycle igniter timing

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

Start-up (continued)

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Weil-McLain GV90+ Gas Boiler

User Manual - Page 65