A carbon monoxide alarm comes before any other fault
If a carbon monoxide alarm sounds, or people in the house have headaches, nausea or dizziness that ease when they go outside, leave the house first. Call 911 or the gas utility's emergency line from outside. Do not try to reset the furnace.
The Ontario Fire Code requires a working carbon monoxide alarm next to each sleeping area in any home with a fuel-burning appliance, a fireplace or an attached garage. That covers nearly every gas-heated house in Caledonia. Test the alarms when the heating season starts.
On the furnace itself, the warning signs are a yellow or lazy flame instead of a crisp blue one, soot or rust around the burners, and a burning or stale smell from the vents. A cracked heat exchanger can let combustion gases into the air the furnace moves through the house. It is the one fault that should not be left running, and the furnace stays off until it is dealt with.
No heat in a newer Avalon home usually starts at the vents or the drain
Avalon and the other new builds in Caledonia have high-efficiency condensing furnaces. They breathe in and exhaust through two plastic pipes in the side wall. A snow drift over those pipes, or frost building on the exhaust during a long cold spell, makes the furnace shut itself off for safety.
Go outside and check both pipes. Clear snow and ice by hand, then switch the furnace off and on at the service switch. If it lights and runs, that was the fault. If the pipes keep icing, the venting may need to be raised or rerouted.
The other common cause is the condensate drain. These furnaces make water, and it has to reach a floor drain or a pump. If the line or the trap is blocked, or the line freezes where it runs near an outside wall, a safety switch stops the furnace. Look for water around the base of the cabinet or a pump that hums but does not empty. Clearing and rerouting drains is a routine repair, and a maintenance visit catches most blockages before winter.
Older chimney-vented furnaces north of the river wear out in familiar ways
Around Shetland Street, many houses from the 1960s still have a standard-efficiency furnace venting into the chimney, or a replacement installed decades ago. These units fail in a predictable order: the igniter cracks, the flame sensor gets coated and stops proving the flame, the inducer motor bearings wear, and the control board starts to act up.
A furnace that clicks, tries to light, then gives up is usually the igniter or the flame sensor. A furnace that hums for a while before anything happens often has a tired inducer or a pressure switch that is not closing. These are ordinary parts and ordinary repairs.
The chimney matters too. Poor draft, a blocked flue or a liner that has broken down can spill exhaust back into the basement. When the furnace is part of the problem and it is also near the end of its life, we give you the repair price and a replacement price, and you decide.
Cold air, short cycling and noises each point to a short list
Cold air from the vents with the furnace running often means the burners have shut off on the high-limit switch while the blower keeps going. The usual cause is a clogged filter or a weak blower. Change the filter, then see if the heat comes back.
Short cycling, where the furnace starts and stops every few minutes, comes from overheating, a dirty flame sensor, a thermostat in a bad spot or a furnace too large for the house. Each one is checked in turn, cheapest cause first.
Noises have their own causes. A bang at start-up is usually delayed ignition from dirty burners. A squeal or grinding is the blower motor or its bearings. A rattle is often a loose panel or a failing inducer. A new noise is worth calling about before the part fails outright.
Older homes around Edinburgh Square need extra care
The oldest houses near Edinburgh Square and Caithness Street were built for wood or coal and converted later. Many have add-on forced air with cramped, retrofitted ductwork, so poor airflow can look like a furnace fault when the ducts are the real limit.
Old pipe and duct insulation in these houses may contain asbestos. If it is suspected, it is not disturbed during the repair, and you are told so you can have it tested. Old chimneys are checked as well, because a chimney that suited the original equipment may not draft properly for the current furnace.
A repair visit follows the same order each time
Before you call, check the thermostat setting and batteries, the service switch beside the furnace, the breaker, the filter and the outside vent pipes. Note any error light code on the furnace door. That information shortens the diagnosis.
The technician confirms the symptom with you, tests the furnace and shows you what was found. You see the written price and approve it before any part is fitted. If the repair is not worth making on an old furnace, you hear that plainly, along with the alternatives, including a heat pump where it suits the house.
Work is performed by TSSA-certified gas technicians, as Ontario Regulation 212/01 requires, and any venting or gas line changes follow the CSA B149.1 installation code. To book, use the quote form or contact us.