Carrier 58DR - Manual (Page 10)

Table 6—Trouble Analysis Chart
A W A R N I N G
To avoid possibility of fixe, explosion, electric shock, personal injury or death, turn off gas and power supply to unit
before servicing (unless specific test requires gas and electric suppHes).
SYMPTOM CAUSE REMEDY
Furnace will not operate
No 115-volt power to furnace Copnnect to power supply. Check fuse, wiring, or circuit breaker.
Blower door not in place Install furnace blower door.
Defective blower door switch Replace switch.
Pilot will not light
Vent safety shut-off switch open Check for vent blockage and proper installation of vent pipe.
No spark at electrode Readjust, if necessary, so that gap between electrode tip
and pilot burner is as shown in Fig. 16.
Clean dirt or moisture accumulation from electrode ceramic with cloth.
Cracked ceramic—replace pilot electrode assembly.
Check for loose or broken wiring at and between spark generator and
electrode. Replace wire or tighten connection as necessary.
Check fuse or circuit breaker for 115-volt supply to furnace.
Check blower access panel for proper installation.
Check 24-volt input to spark generator. If you read 24 volts and above
steps have been completed, replace spark generator assembly.
Spark shorting out to main burner Readjust electrode as specified.
No gas at pilot burner
Clean pilot orifice.
Check voltage to terminals 3 and 5 or TR and TH of gas valve.
Check for proper opening of pilot valve, broken wires, or loose
connections. If no deficiency is found, replace valve assembly.
Burners will not ignite.
No 115-volt power to furnace Connect to power supply. Check fuse, wiring, or circuit breaker.
No 24-volt power to control circuit Replace transformer.
Miswired or loose connections Check all wiring and all wirenut connections.
No gas at main burners Check voltage to terminals 1 and 2 or TR and TH of gas valve.
Check for proper opening of main gas valve, broken wires, or loose
connections. If no deficiency is found, replace gas valve assembly.
Dirty pilot—yellow flame Clean pilot orifice.
Blower operates continuously
Thermostat fan switch in ON position Move thermostat fan switch to AUTO position.
Fusible link blown Correct combustion air, vent system, and/or heat exchanger
blockage—replace fuse link with identical part.
Dirty filter causing limit operating Clean or replace dirty air filter—reinstall.
Defective heat relay Replace printed-circuit board.
Vent safety shut-off switch open Check for vent blockage and proper installation of vent pipe.
Inadequate heating
Furnace undersized for application Replace with proper size furnace.
Gas input to furnace too low Check gas pressure at manifold. Clock gas meter for input. If too low,
increase manifold pressure or install correct orifices.
Limit switch cycles main burners
Clean or replace dirty air filter—reinstall.
Increase blower speed.
Open registers—ductwork restricted.
Manual reset limit switch contacts open Blower motor failure—replace motor.
Manual reset switch contacts open (Burner
on time must be minutes minimum.)
Check and adjust thermostat anticipator to proper setting.
Replace with proper size furnace.
Thermostat anticipator set too low Check thermostat circuit amps and set anticipator accordingly.
See Fig. 6.
Aldehyde odors, (CO),
sooting flame-
floating flame
Incomplete combustion—
poor flame characteristics
Adjust air shutter on burners to provide soft blue flame. Check all
screws around flue outlets and burner compartment. Tighten.
See “Section II, Location & Air for Combustion & Ventilation”
(Procedures for Natural-Draft Gas-Fired Furnaces).
Replace cracked heat exchanger.
Reduce input and check orifices—furnace overfired.
Check vent for restriction.
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