Carrier Furnace Blower Fan Won’t Turn Off in Greater Vancouver — Causes & Repair

A Carrier furnace blower that simply will not shut off — running continuously long after the burners have stopped and the house is warm — is a common and understandably annoying complaint. The good news for a Greater Vancouver homeowner is that a constantly running blower is rarely dangerous, and the most frequent cause is a thermostat setting rather than a failure. But if the fan truly never stops even with the thermostat set correctly, something in the control chain is holding it on, and that is worth diagnosing before it drives up your BC Hydro bill or wears out the motor.

It helps to understand how a Carrier furnace decides to run the blower. The fan is commanded on either by the thermostat (a FAN-ON call) or by the furnace control board during and after a heat cycle, and it is also forced on by the high-limit switch if the furnace overheats. So a blower that won’t quit is telling you one of those signals is stuck on. Carrier shares this control logic with sister brand Bryant, and the troubleshooting is the same across both.

ROMA Heating & Cooling has diagnosed continuous-blower calls on Carrier furnaces across Vancouver, Burnaby, Richmond, Surrey and the North Shore since 1999. Here are the common causes, the safe checks you can do, and when to call.

Most likely causes of a Carrier blower that won’t turn off

Thermostat fan set to ON instead of AUTO

This is by far the most common reason. With the fan set to ON, the blower runs continuously by design, regardless of whether the furnace is heating. Safe check: set the thermostat fan to AUTO and wait a few minutes; if the blower stops after the normal post-heat delay, that was it.

Limit switch stuck closed from overheating

The high-limit switch turns the blower on to clear heat when the furnace runs hot. If a dirty filter or restricted airflow keeps the furnace overheating, the limit stays closed and the fan keeps running. Safe check: replace the 1-inch filter and open all registers so the furnace can shed heat and the limit can reset.

Stuck fan relay on the control board

The board uses a relay to switch the blower. If those contacts weld or stick closed, the blower runs non-stop even with no call. Safe check: none internal; a technician tests and replaces the relay or board.

Thermostat wiring or a stuck G signal

A short between the fan (G) and common wires, or a miswired thermostat, can hold the fan on. Safe check: none — a technician checks the low-voltage wiring.

Failed fan-limit control or blower time delay

A faulty fan-limit control or a stuck blower-off delay can leave the fan energized. A technician tests the control.

Blower-won’t-stop quick-reference

📞 Talk to a licensed ROMA furnace technician — (604) 704-0300

Safe things to try once

Start at the thermostat: set the fan from ON to AUTO and give it several minutes, since Carrier furnaces run the blower for a normal delay after the burners stop before shutting it off. If the fan stops after that delay, the setting was the cause. If it keeps running, replace the 1-inch filter and open all registers so an overheating furnace can shed heat and let the high-limit reset. Then cycle power to the furnace once. If the blower stops and behaves normally afterward, good. If it immediately runs non-stop again with the fan on AUTO, stop and call a licensed technician — a stuck relay, a limit that won’t open, or a wiring fault needs proper testing. Never bypass the limit switch or jump the fan terminals to force it off.

What a ROMA tech checks first

Our technician starts by separating the two easy causes from the real ones. We confirm the thermostat fan is on AUTO and watch a full heat cycle to see whether the blower shuts off after the normal off-delay — if it does, the complaint was a setting. If the fan stays on with no call, we measure whether the board’s fan relay is energized when it shouldn’t be, because a welded or stuck relay is one of the most common hardware causes of a non-stop blower and is a straightforward fix once confirmed.

If the furnace is running hot, we treat the continuous fan as a symptom of overheating rather than the problem itself: a restricted filter, a dirty blower wheel, or a duct restriction keeps the high-limit closed, and the fan is simply doing its job clearing heat. In that case fixing the airflow fixes the fan. We also check the low-voltage wiring for a short on the G (fan) circuit, which can hold the blower on after a thermostat swap. Because Carrier and Bryant share the same fan-control logic, this is a well-understood diagnosis that we resolve efficiently. Everything is confirmed with a meter so we replace the right part.

When you call (604) 704-0300, have this ready:

• The furnace model and serial number.
• Whether the thermostat fan is set to ON or AUTO.
• Whether the furnace feels like it is running hot.
• Whether the constant running started after a thermostat change.

When it’s an emergency

A continuously running blower is usually not an emergency, but the safety rules still hold. If you smell gas, leave the home and call FortisBC emergency and 911 from outside. If a CO alarm sounds or anyone feels unwell, get everyone out and call 911. If the furnace is clearly overheating — a hot cabinet, a burning smell — and the fan is running to clear that heat, shut the furnace off at the switch and call us, since persistent overheating needs attention.

Repair vs. replace

A thermostat setting, a cleaned filter, a fan relay, or a low-voltage wiring repair are all minor, worthwhile fixes that restore normal blower behaviour. A failed fan-limit control or control board is a larger repair but usually still economical on a Carrier with good years left. Replacement only enters the picture when a board failure lands on an aging furnace already needing other work — then comparing the repair to a high-efficiency replacement with BC rebates makes sense. We will give you the honest trade-off rather than pushing new equipment.

Keeping your Carrier blower behaving normally

The simplest prevention is knowing your thermostat: AUTO runs the blower only during and just after heat cycles, while ON runs it continuously — some homeowners prefer ON for even air circulation, which is fine, but then a "won’t turn off" fan is expected behaviour, not a fault. Beyond that, keeping the 1-inch filter clean and registers open prevents the overheating that forces the high-limit to hold the fan on, which is the most common genuine cause we see in Metro Vancouver homes with older ductwork.

The hardware causes — a tiring fan relay, a marginal fan-limit control — are what an annual pre-season tune-up catches. Our technician tests the relay and limit operation, cleans the blower, checks the low-voltage wiring, and confirms the fan starts and stops on schedule through a full cycle. That keeps the blower running when it should and resting when it should. Ask about a maintenance plan when you call and we will keep it in order.

Why ROMA for Carrier furnaces in Vancouver

ROMA Heating & Cooling is a TSBC-licensed gas contractor (Gas licence LGA0202903), bonded, insured and Red Seal-trained, rated 4.8 stars from 221 Google reviews. For a blower that won’t turn off we separate the thermostat setting from a stuck relay, limit, or wiring fault — with upfront flat-rate pricing and no hidden fees. Estimates on installs are free, 0% financing is available OAC, and we work seven days a week. See our furnace repair service or book a free estimate.

We serve Vancouver, Burnaby, North and West Vancouver, Richmond, Surrey, Coquitlam and the Fraser Valley. A non-stop blower is a common Carrier call across Metro Vancouver, and often it is just the fan setting — but when it is a relay or an overheating limit, we find and fix the real cause. Call (604) 704-0300, or reach our team with questions, and ask about maintenance plans.

Frequently Asked Questions

Why won't my Carrier furnace blower turn off?

The most common reason is the thermostat fan set to ON instead of AUTO, which runs the blower continuously by design. If the fan is on AUTO and still won’t stop, likely causes are a high-limit switch stuck closed from overheating or a stuck fan relay on the control board. Set the fan to AUTO first, then call ROMA at (604) 704-0300.

Is it bad for my Carrier blower to run all the time?

It’s usually not dangerous, but a blower that runs non-stop against your wishes wears the motor and raises your electricity use. If you didn’t set the fan to ON and it still won’t stop, the cause — a stuck relay, an overheating limit, or a wiring fault — should be diagnosed rather than left to run.

My Carrier fan runs constantly and the furnace feels hot. What does that mean?

If the furnace is overheating — often from a clogged filter or restricted airflow — the high-limit switch keeps the blower on to clear the heat. Replace the filter and open the registers so the furnace can cool and the limit can reset. If it keeps overheating, shut it off and call a technician.

Should I set my Carrier thermostat fan to ON or AUTO?

AUTO runs the blower only during and just after heat cycles, which is what most people want. ON runs it continuously for constant air circulation, which is a valid preference — but then the fan running ‘all the time’ is normal, not a fault. If you want it to cycle with heat, use AUTO.

Does ROMA fix Carrier blowers that won't shut off in Greater Vancouver?

Yes. ROMA Heating & Cooling separates the thermostat setting from stuck relays, limits and wiring faults on Carrier furnaces across Vancouver, Burnaby, Richmond, Surrey and the North Shore. We are TSBC-licensed, bonded and insured. Call (604) 704-0300 seven days a week.

Reviewed by the ROMA Heating & Cooling team — TSBC-licensed gas contractor (Gas LGA0202903), serving Greater Vancouver since 1999. Updated July 2026.

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