We test it all
We check the thermostat, its settings and the wires back to the furnace. We also check that the furnace responds when it gets the signal.
Thermostat Repair & Wiring
Thermostat Repair in Mississauga
Blank screen, wrong temperature, or a furnace that ignores the thermostat. We test the thermostat and the wires back to the furnace, find the real fault and fix it. Calls answered any hour across Mississauga.
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Price FirstAgreed before any work
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Licensed & InsuredHeating, cooling and gas
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Common Problems
Signs your thermostat needs repair.
Your thermostat is a switch. It tells the furnace and AC when to run. When it fails, you usually see one of these.
- Blank screen. The display stays dead, even with new batteries.
- Wrong reading. It says 21 degrees, but the house feels much warmer or colder.
- No response. You change the setting and the furnace or AC never starts.
- Short cycling. The system turns on and off every few minutes.
- Wi-Fi trouble. A smart thermostat drops offline or keeps restarting.
- Wrong mode. Heat runs when you asked for cooling, or the fan never shuts off.
Many of these come down to a loose wire, a wrong setting or lost power.
Quick Checks
Try these five things before you call.
They take a few minutes and can save you a service call.
- Batteries. If your thermostat takes them, put in fresh ones.
- Breaker and furnace switch. Check the furnace breaker in your electrical panel. Then find the switch on or near the furnace. It looks like a light switch and should be on.
- Settings and schedule. Make sure it is on Heat or Cool, not Off. Set it a few degrees above room temperature for heat, or below it for cooling. Check that a schedule or hold is not overriding you.
- Furnace filter. A clogged filter can make the furnace overheat and shut itself off. That looks like a thermostat fault, but it is not. See filter replacement.
- "Wait" on the screen. Many thermostats pause for a few minutes after a change to protect the AC. Give it five minutes.
Stop there. Do not open the furnace beyond changing the filter. If these checks do not fix it, call us on (647) 280-6626. We answer any hour.
Thermostat Wiring
Thermostat wiring, explained simply.
Your thermostat does not make heat. It sends a small signal down thin wires to the furnace, telling it when to start and stop.
- Each wire has one job, such as heat, cooling, the fan or power
- A loose wire, or one on the wrong terminal, means the system ignores you or runs the wrong thing
- Wires often get mixed up when a thermostat is swapped without labelling them first
- Most smart thermostats need a C wire, short for "common" wire. It gives the thermostat steady power
- Without one, a smart thermostat can go blank, drop off Wi-Fi or keep restarting
- No C wire? We connect a spare wire if there is one, run a new one, or fit an adapter at the furnace
We test the wiring at both ends, at the thermostat and at the furnace. That is how we find a broken wire hidden inside a wall.
Process
How a thermostat repair works.
Call (647) 280-6626 or send the form. We are based in Churchill Meadows and cover all of Mississauga. Then it goes like this.
You see the fault and the price
We show you what is wrong and what it costs to fix. You agree the price in writing before any work starts.
We fix it or replace it
We repair the wiring, power or settings. If the thermostat itself has failed, we replace it and set it up for your system.
Sometimes the thermostat is fine and the fault is in the furnace. If so, we tell you, and it becomes a furnace repair instead.
Repair or Replace
When a new thermostat makes more sense.
Plenty of faults are a simple repair. Some thermostats are not worth fixing.
- Old dial or mercury thermostats. They drift out of accuracy and cannot run a schedule. Replacing one is usually worth it.
- Mercury must be recycled. If you see a small glass bulb under the cover, it holds mercury. Never put it in the garbage. Take it to a household hazardous waste drop-off.
- It keeps failing. A thermostat that keeps losing its settings or locking up is near the end.
- You want more control. A smart thermostat runs a schedule and lets you adjust it from your phone.
Replacing it? A smart Wi-Fi thermostat, installed and set up, is $350 + HST. See thermostat installation and our pricing list. Repairs are priced on the fault, and you agree the price before work starts.
Thermostat not working right?
Call or send the form and we will find the fault and give you the price before any work starts.
Rather just talk? Call (647) 280-6626. We answer any hour. Licensed and insured, and you agree the price before any work starts.
FAQ
Thermostat repair FAQs.
Why is my thermostat screen blank?
Change the batteries first, if it takes them. Then check the furnace breaker and switch. If a furnace door was taken off, make sure it is back on properly, because most furnaces cut power while it is off. Still blank? It may be a loose wire or a blown fuse in the furnace. We can trace it.
Why does my thermostat show one temperature when the house feels different?
A thermostat only measures the air right around it. Sun on the wall, a lamp, a nearby heat vent or a draft from a stairway can all fool it. So can dust inside the case. Older thermostats also drift with age. We compare the reading with our own thermometer and fix the cause.
My furnace will not turn on when I raise the thermostat. Is the thermostat to blame?
Sometimes. Check that it is set to Heat, set a few degrees above the room, and not held back by a schedule. If the furnace still will not start, we test whether the thermostat is sending the signal. If it is, the fault is in the furnace, and we handle the furnace repair.
My smart thermostat keeps going offline or restarting. Is it the C wire?
Often, yes. A smart thermostat needs steady power. Without a C wire, the common wire that supplies it, many models borrow power through the other wires. That can work for a while, then cause dropouts, restarts or a furnace that starts and stops on its own. We add a C wire or fit an adapter at the furnace.
Can you fix thermostat wiring that someone else installed?
Yes. A do-it-yourself swap or a rushed install can leave wires on the wrong terminals, a loose connection, or the thermostat set up for the wrong type of system. We trace each wire back to the furnace, label it, connect it properly and set the thermostat up for your equipment. You agree the price first.
Should I repair or replace my old thermostat?
If it is fairly new and the fault is a wire, a setting or power, repair it. If it is an old dial or mercury thermostat, or it keeps failing, replacing it usually makes more sense. A smart Wi-Fi thermostat installed and set up is $350 + HST. An old mercury thermostat must be recycled, never put in the garbage.
How much does thermostat repair cost in Mississauga?
It depends on the fault. A loose wire is a different job from running a new wire to the furnace. We test first, show you what is wrong, and you agree the price in writing before work starts. If replacing makes more sense, a smart Wi-Fi thermostat installed and set up is $350 + HST on our pricing list.
Can a bad thermostat make my furnace short cycle?
Yes. Short cycling means the furnace starts and stops every few minutes. A thermostat next to a heat vent or in a draft, a loose wire, or the wrong cycle setting can all cause it. So can a clogged filter or a furnace fault. We check the thermostat first, because it is the easiest thing to rule out.
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