Greenheck IG / IGX (464104 IOM) (Pre-2009) - Manual (Page 69)

69
Internal control failure?
(ignition controller(s) LED on)
Ignition controller(s) (IC#) failed
Replace faulty ignition controller(s)
High limit switch (HLC#) open?
Discharge temperature was above high limit setting
Let cool then reset high limit.
Yes
Yes
No
Airflow fault?
(ignition controller LED
blinking once)
Pressure switch (PSL) failure
Repair or replace pressure switch (PSL)
Combustion blower (CM#) not functioning
Replace fusing (FU9), combustion blower or relay (CM#)
Yes
No
Ignition lockout?
(ignition controller LED
blinking three times)
Improper manifold pressure
Set high and low manifold pressure (refer to 4:1 mod. start-up)
Faulty spark rod or spark gap does not equal 1 ⁄
8
in.
Replace spark rod or adjust gap to 1 ⁄
8
in.
Yes
No
120 VAC between terminals
101 and 102?
...continued from previous
page
Secondary fuse (FU7) blown
Replace secondary fuse (FU7)
Main transformer (TR1) defective
Replace main transformer (TR1)
Secondary transformer (TR2) defective
Replace secondary transformer (TR2)
A200 defective
Replace A200
Furnace controller (FX) defective
Replace furnace controller (FX)
No
No
Yes
24 VAC between terminals
1 and 2 on the A200
No
Yes
24 VDC between terminals
3 and 4 on the A200
No
Yes
10 VDC between terminals
5 and 6 on the A200
Everything is working
properly, consult factory.
No
Yes
4:1 Modulating Furnace Will Not Light
Troubleshooting
Troubleshooting