Heat Pump Questions, Answered

A cold-climate heat pump keeps producing heat through any normal Burlington winter.

Most of the time it is not cold air, it is heat pump air.

A light coat of frost on the outdoor coil in damp weather near freezing is normal; the defrost cycle clears it, usually within an hour or two.

A modern variable-speed heat pump is typically rated somewhere around 50–65 dB(A) outdoors at full speed, and it is quieter at the part-load speeds it runs most of the time — roughly the level of a normal conversation or a dishwasher heard through a wall.

An air-source heat pump in Ontario typically lasts 12 to 15 years, and a well-installed, well-maintained unit often reaches 15 to 20.

A heat pump tune-up in the Burlington, Oakville and Hamilton area runs $120–$250 per visit.

Not necessarily.

Yes.

A whole-home heat pump draws roughly 1 to 4 kilowatts while the compressor runs, and adds several hundred kilowatt-hours a month to a typical Burlington hydro bill through the heating season.

For most Burlington homes it lowers total energy cost, but it does so by shifting spending from the Enbridge gas bill to the Burlington Hydro bill rather than by cutting either one alone.

Size comes from a CSA F280-12 heat loss and heat gain calculation done on your actual house, not from square footage or the size of the old air conditioner.

A straight swap — a heat pump replacing an existing air conditioner on a working furnace — takes one day, usually six to nine hours on site.

Yes, but not by connecting a heat pump to whatever radiators are already there.

Yes.

No.

Long run times are normal.

A heat pump that will not turn on usually has a tripped breaker, a pulled outdoor disconnect, or a thermostat left in emergency heat or held off by an outdoor-temperature lockout.

A mini-split leaking water inside almost always has a drain problem: a condensate hose blocked with slime, an indoor head mounted without slope, or a drain run that is kinked or climbs uphill inside the wall.

A blinking light on a mini-split is the unit reporting its status.

A mini-split that is not cooling is most often short of airflow or short of refrigerant.

A mini-split that is not heating is often in a normal pause: defrost and the cold-air-prevention delay stop the indoor fan for up to 15 minutes.

Auxiliary heat that is always on means either the thermostat is calling for backup too easily or the heat pump has stopped producing heat.

Use emergency heat only when the heat pump's outdoor unit cannot run: it has failed, iced over or been damaged.

A mini-split that smells bad usually has mould and biofilm on the blower wheel and coil, a musty 'dirty sock' odour that washing the filters does not remove.

If your heat pump is covered in snow, switch the system off or to emergency heat, then clear the snow by hand or with a soft brush from around, above and beneath the unit until it has 30–60 cm of open space on every side.

A heat pump making a loud noise is normal when it is a whoosh and hiss lasting a few seconds, the reversing valve shifting at the start and end of defrost, or a steady drone from the inverter compressor in deep cold.

A heat pump stuck in cooling mode has a reversing valve that is not shifting.

A heat pump is short cycling when the compressor runs less than about 10 minutes, shuts off and restarts, over and over.

To defrost a frozen heat pump, switch the thermostat to Emergency Heat or Off, clear snow from around and under the outdoor unit, and let the ice melt.

A mini-split that won't turn on has usually lost power or lost its remote signal.

A heat pump fan that is not spinning is normal during a defrost cycle, which lasts 5 to 15 minutes, and on inverter units once the house is at temperature.

A mini-split remote stops working for four reasons: weak batteries, a child lock, a blocked or failed infrared receiver on the head, or a dead remote.

Most mini-split clicking and gurgling is normal.

Yes.

When one mini-split head is not working and the others are, check the modes first.

Daikin error code A5 means freeze-up protection control in cooling, when the indoor coil drops below 0 °C, or heating peak-cut control in heating, when the indoor coil climbs above roughly 60–65 °C.

Daikin error code U0 means refrigerant shortage.

Daikin error code U4 means a signal transmission error between the indoor unit and the outdoor unit: the two halves of the system have stopped talking, so heating and cooling stop.

Gree error code E6 means a communication malfunction between the indoor and outdoor units.

Error CH05 on an LG mini-split is a communication error between the indoor and outdoor units.

Mitsubishi error code E6 is an indoor/outdoor unit communication error: the indoor unit has detected a signal-receiving error on the link to the outdoor unit.

Mitsubishi error code P8 means abnormality of pipe temperature: the indoor pipe temperature is not changing the way the heating or cooling mode demands.