Carrier 580PB - Manual (Page 17)

HEATING & COOLING
58ED,PB
Horizontal Gas-Fired Furnaces
Table 8 — Trouble Analysis Chart for Electronic ignition Modeis
A WARNING
Turn off gas and electrical supplies to furnace before servicing (Unless specific
test requires gas and electrical supplies.)
SYMPTOM AND PROBABLE CAUSE REMEDY
PILOT WILL NOT LIGHT
1 No spark at electrode
1 Check spark gap, refer to Start-Up and Adjustment section
Check if Induced draft motor is operating If not, check power
to motor
Check for any blockage in flue venting system and chimney,
thereby preventing pressure switch from closing Unblock
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
control box and electrode. Replace wire as necessary
Check fuse or circuit breaker for 115-v supply to furnace
Check 24 v input to electronic control box If you read 24 v,
and above steps have been completed, replace electronic
control box assembly
Check pressure switch and tube assembly for any blockage
that prevents pressure switch from operating
Check continuity to determine if pressure switch has
disengaged
2 Spark shorting out to main burner 2 Realign electrode tip away from main burner but maintain
spark gap to pilot burner as noted above
3. No gas at pilot burner 3 Check to see if pilot valve is opening Look for loose or broken
wiring connections If no deficiency is found, replace valve
assembly
BURNERS WILL NOT IGNITE
1 No 115-v power to furnace
1 Connect to power supply Check fuse, wiring or circuit
breaker
2. No 24-v power to control circuit 2 Check transformer; replace
3. Miswired or loose connections 3 Check all wiring and wirenut connections
4 No gas at main burners 4 Check to see if main valve is operating. Look for loose or
broken wiring connections If no deficiency is found, replace
valve assembly
5 Flame probe or connecting lead is shorted or open 5. Correct electrical shorting or open circuit
INADEQUATE HEATING
1. Furnace undersized for application
1 Replace with proper size furnace
2 Gas input to furnace too low 2 Check gas pressure at manifold Clock gas meter for input.
If too low, increase manifold pressure, or replace with correct
orifices
3 Limit switch cycles main burners 3 OFF setting of fan control set too high, reset
Dirty air filters, clean and reinstall.
Blower speed too low, use faster speed tap
Registers closed, restricted ductwork, open or remove
restriction.
Check heat anticipator setting on thermostat; readjust
ALDEHYDE ODORS (CO), SOOTING FLAME,
FLOATING FLAME
1 Incomplete combustion — poor flame characteristics
1 Air shutter on burners closed, adjust to soft, blue flame
Check all screws around flue outlets and burner compart­
ment; tighten
Lack of combustion air, see Installation section
Cracked heat exchanger, replace
Overfired furnace; reduce input or change orifices
Check vent for restriction; clean as required
Book|1 [4 PC101 Catalog No 535-834 PrintedinUSA Form 58ED,PB-1SI Pg17 6-85 Replaces: 58PB-1 SI
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Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.