Carrier 58GS - Manual (Page 14)

Table 4 — Trouble Analysis Chart
WARNING: Turn off gas and power supply to ur»it before servicing.
(Unless specific test requires gas and electrical supplies.}
CAUSE
No spark at electrode
Blower operates continuously
Inadequate heating
Aldehyde odors, (CO),
sooting flame — floating flame
Spark shorting out to main burner
No gas at pilot burner
N o l l 5-volt power to furnace
No 24-volt power to control circuit
Miswired or loose connections
No gas at main burners
Flame probe or connecting lead is
shorted or open
Dirty pilot — yellow flame
Thermostat fan switch in ON position
Fusible link blown
Dirty filter causing limit operation
Defective heat relay
Furnace undersized for application
Gas input to furnace too low
Limit switch cycles main burners
REMEDY
Check air gap between electrode tip and pilot burner It should
be 1/8 +1/16 on BDP gas valve; 3/32 +0 025 onEssexgas
-0 -0.005
valve Readjust if necessary
Check moisture or dirt accumulation on electrode ceramic —
clean ceramic with cloth
____ _ _
Cracked ceramic — replace pilot electrode assembly
Check for loose or broken wiring at and between electronic con­
trol box and electrode Replace wire as necessary_____________________
Check fuse or circuit breaker for 11 5-volt supply to furnace.
Check 24-volt input to electronic control box If you read 24 volts
and above steps have been completed, replace electronic
control box assembly
Realign electrode tip away from main burner but maintain
spark gap to pilot burner as jtote^above
___ __
Check to see if pilot valve is opening Look for loose or broken
wiring connections If no deficiency is found, replace valve
assembly
Connect to power supply Check fuse, wiring, or circuit breal^r
Check transformer — replace
Check_all wiring and wirenut connections._______________________ _
Check to see if main valve is opening Look for loose or broken
wiring connections If no deficiency is found, replace valve
assembly
_
Correct electrical shorting or open circuit
Incomplete combustion — poor
flame characteristics
Clean pilot orifice
Move thermostat fan switch to AUTO position
Correct combustion air and venting practice — replace fuse
link with identical part
___ ______
Clean dirty air filter — reinstall
Replace printed circuit board
Replace with proper size furnace _
Check gas pressure at manifold Clock gas meter for input If
too low, increase manifold pressure, or replace with correct
orifices
pFF setting of fan control set too high — reset. ____ _
Dirty air filters — clean and reinstall.
slower speed too low — use faster speed tap
Registers closed, restricted ductwork — open or remove
restriction
Check heat anticipator setting on thermostat — readjust
Air shutter on burners — closed — adjust to soft blue flajjip^
Check all screws around flue outlets and burner compartment
— tighten
LACK OF COMBUSTION AIR — see instructions.
Cracked heat exchanger — replace.
Overfired furnace — reduce input, or change orifices
Check vent for restriction — clean as required
14