Furnace Repair in Denver

A furnace that quits on a cold Denver night usually stops at one specific step of its start-up sequence — and knowing which step narrows the repair down fast. Best Pro repairs gas furnaces in homes across Denver and the metro area.

How a furnace starts — and where it fails

1. The thermostat calls for heat. No response at all points to the thermostat, its wiring, a tripped breaker or the furnace door switch.
2. The inducer motor starts to clear the exhaust, and a pressure switch confirms the draft. A blocked vent pipe, a failed inducer or a cracked pressure switch hose stops the furnace here.
3. The igniter glows and the gas valve opens. A cracked hot-surface igniter is one of the most common winter repairs.
4. The flame sensor proves the flame. If the burners light and then shut off after a few seconds, the flame sensor is usually dirty; cleaning or replacing it fixes it.
5. The blower comes on. A failed blower motor or capacitor means the furnace heats up but no warm air comes out — and it will then shut down on the high-limit switch.

Most furnaces flash an error code on a light inside the cabinet. Count the blinks before you turn the power off; switching the power off and on clears the code.

Denver-specific problems

• Snow and ice blocking the vent pipes. High-efficiency furnaces vent through white plastic pipes on the side of the house. When drifting snow or ice blocks them, the furnace shuts off. Clear them gently and keep them clear.
• Frozen or clogged condensate drain. The same furnaces produce water. A clogged trap or a drain line frozen outside makes the furnace shut off or leak.
• Short cycling. Often a clogged filter making the furnace overheat and trip the high-limit switch.

Safety

If you smell gas, leave the house and call your gas company from outside. Keep carbon monoxide detectors working near bedrooms and on every floor. During each repair we check the burners, the venting and the heat exchanger for signs of trouble.

Tune-ups

A furnace cleaning and tune-up before the heating season — burners, flame sensor, igniter, blower, filter and venting — prevents most no-heat calls in January. HVAC prices are on our prices page. Air conditioning problems? See air conditioner repair.