Greenheck Fan 470656 manual 2:1 Modulating Furnace Will Not Light, Troubleshooting

Troubleshooting

2:1 Modulating Furnace Will Not Light

24 VAC across R and X?

Yes

24 VAC across W1 and X?

Yes

24 VAC across S and T?

Yes

24 VAC across C and T?

Yes

24 VAC across A and T?

Yes

Ignition controller (IC#) red LED

blinks 7 times or is on

No

Ignition controller (IC#) red LED

blinks 6 times

No

Ignition controller (IC#) red LED blinks

1 time, 2 times or 4 times

Yes

Everything is working

properly, consult factory.

No

No

No

No

No

Yes

Yes

Yes

Main disconnect (DS1) open or defective

Close, repair or replace

Main transformer (TR1) fault

Replace main transformer

Heat switch (S4) open or not wired

Close or replace heat switch (S4)

Heat transformer (TR5) fault

Replace heating transformer

Discharge temperature was above high limit control (HLC1)

Wait for high limit to cool and reset.

Optional inlet air sensor contact (TS4 open)

Adjust setting reference Blower Start-Up, Step #6

Heat relay (RH) is not energized

Check for loose connections. Repair or replace heat relay (RH)

Discharge air selector (TS3) improperly set or faulty

Adjust setting (see staged start-up) or replace sensor

Ignition controller (IC1) failed

(Replace ignition controller)

Combustion blower (CM) not functioning

Replace combustion blower or relay (CM)

Air proving switch (PS2) defective

Replace air proving switch

Improper manifold pressure

Set high and low manifold pressure (refer to the 2:1 Electronic

Modulation Start-Up section)

Faulty spark rod or spark gap does not equal 1/8 inch

Replace spark rod or adjust gap to 1⁄8 inch

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Model IG / IGX Make-Up Air 51