Carrier furnace — Carrier deluxe two-stage gas-fired induced-combustion furnaces with PSC or ICM blower motors, per troubleshooting guide 58-3T Error Codes Directory
Complete diagnostic reference for Carrier furnace — Carrier deluxe two-stage gas-fired induced-combustion furnaces with PSC or ICM blower motors, per troubleshooting guide 58-3T fault codes. Each code includes official root causes, safety precautions, and affected replacement components.
Carrier status code 24: the secondary voltage fuse is open
Carrier defines status code 24 as the secondary voltage fuse being open. That fuse protects the 24-volt control circuit, and the guide specifies a 3 amp automotive blade type that must be replaced only with another 3 amp fuse. A fuse opens because something drew more current than the circuit allows, so the fuse is the symptom. Applies to: Carrier deluxe two-stage gas-fired induced-combustion furnaces with PSC or ICM blower motors, per troubleshooting guide 58-3T The fuse rating and the code definition come from Carrier troubleshooting guide 58-3T for deluxe two-stage induced-combustion furnaces. Fuse ratings differ between control platforms, and fitting anything other than the rating in the literature for your exact model removes the protection the circuit was designed around. Owner-safe checks: Establish exactly what has stopped: heating alone, heating and cooling together, or any accessory such as a humidifier. | Check whether the thermostat display is blank or still powered, since that alone tells the technician which side of the circuit lost supply. | Write down any recent work on thermostats, cabling, outdoor equipment, or the building fabric in the weeks beforehand. Qualified technician: Locating a short in the 24-volt circuit, testing the transformer, and replacing the control fuse are tasks inside an enclosure that also carries line voltage, so they belong to a qualified technician. | Never fit a fuse of a higher rating than the literature specifies. The protection the original rating provides is the reason the transformer and board survived the fault.
Carrier status code 32: three switches share one number
Carrier writes status code 32 as the low-heat pressure switch, the draft safeguard switch, or the downflow auxiliary limit switch failing to close or reopening after it had closed. Three separate devices share the entry, and the control cannot tell you which one acted, so the code narrows the fault to a group rather than to a part. Applies to: Carrier deluxe two-stage gas-fired induced-combustion furnaces with PSC or ICM blower motors, per troubleshooting guide 58-3T Guide 58-3T is the source here, and it covers deluxe two-stage induced-combustion equipment only. The auxiliary limit named in the entry is present on downflow arrangements, so what the code can mean depends on how your furnace is installed as well as on which model it is. Owner-safe checks: Look at the outdoor vent and intake terminations from ground level and note any ice, snow, nesting material, or vegetation without attempting to clear anything at height. | Time how long the furnace produces heat before it stops, and whether the burners lit at all. | Keep a short log of the outdoor temperature and wind conditions each time the code appears. Qualified technician: Measuring draft pressure, inspecting the vent system, clearing condensate traps, and testing pressure switches are licensed gas-furnace tasks. | Combustion products detected indoors, or a carbon monoxide alarm sounding, outranks every other instruction on this page. Get people out, open up the space, and call the emergency line your gas supplier publishes.
Carrier status code 34: ignition proving failed on this trial
Carrier lists status code 34 as an ignition-proving fault. It records that a trial for ignition did not end with a proven flame, and unlike code 14 it does not mean the control has given up. Seeing 34 without 14 means the furnace is still retrying, which is the moment when observing what happens is worth most. Applies to: Carrier deluxe two-stage gas-fired induced-combustion furnaces with PSC or ICM blower motors, per troubleshooting guide 58-3T Read here from Carrier troubleshooting guide 58-3T for deluxe two-stage induced-combustion furnaces. The relationship between the per-trial fault and the lockout that follows it is specific to this control family, and other manufacturers using the number 34 are not describing the same thing. Owner-safe checks: Listen to a full heating cycle from a safe distance and note whether a flame is established at all, and whether it is lost after establishing. | Keep a tally over several days of how many heat calls succeed and how many fail, with the times of day. | Confirm that other gas appliances behave normally and note whether failures coincide with their use. Qualified technician: Measuring the flame signal, testing igniter resistance, cleaning a sensing electrode, and checking manifold gas pressure are licensed gas-furnace tasks. | Any smell of gas requires the emergency response for your supplier before any further troubleshooting: leave the property, avoid switches, and call from outside.