Heat pump repair in Scarborough, Durham and the GTA
A heat pump is an air conditioner that can run backwards, and almost everything that goes wrong with one falls into three groups: a refrigerant-side fault, an airflow restriction, or a control problem in the reversing and defrost circuit. Metropolitan Heating and Air Conditioning has worked on heat pumps across Scarborough, Durham Region and the GTA since 1979, on all makes and models.
Call (416) 283-5698, Monday to Friday 8:00 AM to 4:00 PM.
Frost on the outdoor coil is normal. Ice is not.
In heating mode the outdoor coil sits colder than the outdoor air, so moisture condenses on it and freezes. Every heat pump answers this by reversing into cooling for a few minutes, warming the coil until the frost sheds, then switching back. Steam rolling off the cabinet and water pooling beneath it afterwards is the system working as designed.
What is not normal: a coil encased in solid ice, frost that never clears across several hours of mild weather, the base of the cabinet frozen into a block, or defrost cycles firing every few minutes. Those point to a failed defrost sensor or board, a reversing valve that is not shifting, a drain path that cannot clear meltwater, or a low refrigerant charge. Ice reaching the fan blades will damage the fan, so shut the unit off at the thermostat rather than chipping at it.
What the other symptoms usually mean
- Grinding, rattling or squealing. Mechanical — a fan or blower bearing, a loose blade, or a compressor under strain. Bubbling or hissing is different, and often means refrigerant escaping.
- Short cycling. Starting and stopping every few minutes, usually from a thermostat fault, low charge, or a system oversized for the house.
- Backup heat running constantly. If the auxiliary or emergency heat indicator stays lit in moderate weather, the heat pump is not carrying the load. That is a fault, and an expensive one, because resistance heat costs far more to run than the compressor.
- Lukewarm supply air. Heat pump supply air is normally cooler to the hand than furnace air, which is not a defect. Air that is genuinely cool with the system calling for heat is.
- Nothing happens at all. Electrical: a tripped breaker, a failed contactor or capacitor, a blown low-voltage fuse, or a thermostat that has lost its link to the outdoor unit.
Why the outdoor temperature changes the diagnosis
Heat pump capacity falls as the outdoor air gets colder, because there is less heat available to move. Every installation therefore has a balance point — the outdoor temperature at which the heat pump's output exactly matches the house's heat loss. Below it, backup heat makes up the difference.
That matters for troubleshooting. A system that keeps up in November but struggles in a deep cold snap may be behaving as designed. A system that cannot keep up at 0 °C has a real fault. Which of those you have is part of the diagnosis, and it is why we ask what the outdoor temperature was when the problem started.
How we work through a heat pump fault
We start from the symptom and verify rather than assume. A visit typically covers the thermostat, filter condition and static pressure, refrigerant pressures and superheat in the mode that is failing, the reversing valve and defrost board, both coils, electrical measurements at the contactor and capacitors, and the condensate path.
Refrigerant is not consumed in normal operation. If the charge is low there is a leak, and adding refrigerant without finding that leak only postpones the same failure — usually to the coldest part of the season. We will look for the leak and tell you what correcting it involves.
You get the finding before any work begins — what failed, and what it takes to put right.
When repair stops being the answer
Repair is usually right on a system with a single identifiable fault and a sound compressor. It stops being right when the compressor has failed, when the unit runs a refrigerant that is no longer produced, or when you are facing a third significant repair in as many seasons. In those cases we will price repair and replacement side by side so you can compare them honestly. Financing is available through Vista.
Related services
- Heat Pump Maintenance & Tune-Up — the service that catches most of the faults above
- Heat Pump Installation & Replacement
- Ductless mini-split systems
- All heat pump services
Book a heat pump repair
Call (416) 283-5698 weekdays between 8:00 AM and 4:00 PM, or send us the details. Have the make, model and rough age of the outdoor unit to hand. Licensed and insured, all makes and models, including Carrier, Lennox, Napoleon, Trane, Bosch and Daikin.