Stage - Greenheck PVF Installation And Operation Manual

Troubleshooting
8 Stage Furnace Will Not Light
In all cases, verify correct terminals as shown on the unit-specific wiring diagram.
24 VAC across R and C?
Yes
24 VAC across W1 and C?
Yes
24 VAC across 22 and 21?
Yes
N.O. contact on heat relay (RH)
closed?
Yes
DT1 displayed on furnace
controller (SC1)?
No
OT1 displayed on furnace
controller (SC1)?
No
Blank screen on furnace
controller (SC1)?
No
24 VAC across terminals
S and T?
Yes
With the combustion blower
(CM) off, is the N.O.
airflow switch (PS2) closed?
No
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26 Indirect Gas-Fired Heat Modules
No
Main disconnect (DS1) open or defective
No
Heat switch (S4) open or not wired
No
No
Check for loose connections. Repair of replace heat relay (RH)
Yes
Discharge air sensor (TS2) not wired or defective
Wire or replace discharge air sensor (TS2)
Yes
Outdoor air sensor (TS1) not wired or defective
Wire or replace outdoor temperature sensor (TS1)
Yes
Furnace controller (SC1) defective or not powered
Replace or wire furnace controller (SC1)
No
Discharge temperature was above high limit control (HLC1)
(refer to Reference - FX Controller, Access the Inlet Air Sensor section)
Furnace controller (SC1) defective
Yes
Close, repair or replace
Main transformer (TR1) fault
Replace main transformer
Close or replace heat switch (S4)
Heat transformer (TR2) fault
Replace heating transformer
Heat relay (RH) is not energized
Wait for high limit to cool and reset
Inlet air sensor contact open
Adjust inlet air sensor setting
Replace furnace controller (SC1)
Airflow switch (PS2) defective
Replace defective airflow switch (PS2)
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