Greenheck IGK (472084) - Manual (Page 15)

15 Model IGK Make-Up Air
®
Troubleshooting
2:1 Staged Furnace Will Not Light
24 VAC between
terminals A and X?
Stage one controller (SC1) improperly set or defective
Adjust setting (see Furnace Start-Up) or replace stage one controller
Discharge air sensor (TS2) faulty
Replace sensor
Ignition controller (IC) failed
Replace ignition controller
24 VAC between
terminals S and X?
High limit (HLC) open
Discharge temperature was above high limit setting
Wait for high limit to cool and reset
24 VAC between Motor Starter
(ST1) terminal 14 and X?
Supply fan overload (ST1 OL) tripped
Reset and check motor amps, reference Blower Start-Up Step #4
Supply starter relay (ST1) defective
Replace supply starter relay
No
No
No
Yes
Yes
24 VAC between
terminals W1 and X?
Optional heat switch (S3) open or not wired
Close, install or replace heat switch
No
Yes
24 VAC between
terminals R and X?
Main disconnect (DS1) open or defective
Close, repair or replace
Main transformer (TR1) fault
Replace main transformer
No
Yes
Internal control failure?
(ignition controller LED on)
Combustion blower (CM) not functioning
Replace combustion blower (CM) or combustion relay (CR)
Air proving switch (PS2) defective
Replace air proving switch
Yes
Yes
Airflow fault?
(ignition controller LED
blinking once)
Improper manifold pressure
Set high and low manifold pressure (refer to Furnace Start-Up)
Faulty spark rod or spark gap does not equal 1/8 inch
Replace spark rod or adjust gap to 1/8 inch
Faulty flame sensor or sensor electrode is grounded
Replace sensor or correct grounding problem
Yes
Yes
No
Ignition Lockout?
(ignition controller LED
blinking three times)
Everything is working
properly, consult factory.
No
No
Heating inlet air sensor
contact (TS1) open?
Adjust inlet air sensor setting
Refer to Blower Start-Up
No
Yes