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Heating · Electric RepairElectric Furnace Repair
Electric furnace repair is mostly electrical fault-finding on four parts: the heating elements, the sequencers or contactors that switch them, the thermal limits and the blower. If the blower runs and the air is cool, an element bank or its sequencer has failed; if a 240-volt breaker trips, stop resetting it and call. The diagnostic visit is $90–$150 and most repairs run $150–$800.
An electric furnace has no burner, gas valve or flue, so its failures are not the ones a gas furnace has. Heat comes from banks of coiled resistance wire, usually around 5 kW each. Sequencers, which are small time-delay relays, or contactors bring the banks on one at a time so the house does not see the whole load at once. Each bank is protected by a thermal limit that resets itself and a fusible link that does not.
The symptom tells us where to start. Cool air with the blower running means no element is energised: a failed first-stage sequencer, an open limit, or a tripped element breaker while the blower circuit stays live. Heat that is only lukewarm, or a furnace that keeps up in October and falls behind in January, means one bank is dead and the others are carrying on. A breaker that trips points to an element that has sagged and grounded against the cabinet, a loose lug that has overheated, or a tired breaker.
We measure before replacing anything. Each 5 kW element should draw about 21 amps at 240 volts, so a clamp meter on each stage shows immediately which bank is open. With the power off we check element resistance, look for a blown fusible link, and inspect every lug and wire for the browned insulation a loose connection leaves behind. A blown link is a symptom: the elements ran without enough airflow, so the filter, the blower and a sequencer stuck closed are all checked before the furnace goes back on.
Parts inside the furnace are appliance repair. Work on the supply circuit, meaning a new breaker, damaged feeder conductors, a disconnect or anything in the panel, is electrical installation work that in Ontario belongs to a Licensed Electrical Contractor with a notification filed with the Electrical Safety Authority. If we find heat damage that runs back into the supply wiring, we make the furnace safe, show you the damage and bring in the electrical contractor. For gas units, see furnace repair.
Signs an electric furnace needs repair
- The blower runs and the air from the registers is room temperature
- The house holds temperature in mild weather but cannot keep up in a cold snap: one element bank is out
- A double-pole breaker for the furnace trips, or trips again after one reset
- A hot, sharp electrical smell that lasts beyond the first hour of the season, when dust burning off the elements should already be gone
- The furnace heats but the blower hums, starts slowly or does not start at all
How it works
Say whether the blower runs, whether any heat comes out and whether a breaker has tripped. If one has tripped twice, leave it off; a breaker that will not hold is protecting the wiring from a real fault.
We take amp draw on every element stage, voltage at the furnace lugs under load, and resistance on the elements and limits with the power locked off. The readings identify the failed part, and you see them.
The failed element, sequencer or limit is replaced, every power connection is re-torqued, and the furnace is run through all stages while we measure the temperature rise against the nameplate. We check the filter too, since a loaded one is how limits and links get tripped.
Common questions
Why does my electric furnace blow cold air?
The blower and the elements are on separate circuits, so the fan can run with no heat behind it. The usual causes are a failed sequencer, an open thermal limit or fusible link, or a tripped element breaker in the panel or on the furnace itself. Check both sets of breakers once. If they are on and the air is still cool, the fault is inside and needs a meter.
Is it safe to keep resetting the breaker?
No. Reset it once; if it trips again, leave it off. A furnace breaker trips because of a grounded element, a failing connection that is overheating or a breaker at the end of its life, and each reset puts full current back through the fault. Use portable heaters on separate circuits to protect the pipes and call for a repair visit.
Is it worth repairing an old electric furnace?
Usually, yes. An electric furnace has no heat exchanger to crack, and elements, sequencers and limits are inexpensive next to a new furnace, so repair makes sense at almost any age. The exceptions are a cabinet with widespread heat-damaged wiring, or a blower failure on a unit you already planned to replace. In that case price electric furnace installation against a heat pump first.
Why is my electric heating bill so high when the furnace works?
Resistance heat turns one unit of electricity into one unit of heat, and no repair changes that. A failed sequencer can make it worse by leaving elements on longer than needed, and leaky ducts or a clogged filter add to it. If the bill is the real complaint, a heat pump is the fix; the numbers are in electric furnace vs heat pump.
Do you repair electric furnaces on rural properties?
Yes. Most of the electric furnaces we see are on rural lots without a gas main, in Caledon, Campbellville, Kilbride, Carlisle and rural Flamborough, along with some townhouse complexes built all-electric. Those areas are inside our normal service area from the Burlington shop. Give us the make and the kilowatt rating from the nameplate when you call so we can bring the likely parts.