Heat pump not heating?
Check the pressure gauge, the controls and the outdoor unit first. Low pressure, a blocked filter, ice on the outdoor unit or a changed setting cause most of the calls. If those are fine, or an error code keeps coming back, book a repair.
Free, no obligation. One local company prices it, not five.
- 8 checksyou can make safely
- About 1 barbelow this, the pump may stop
- €140 to €400a fault call-out with a minor repair
- Defroststeam and a pause are normal
Heat pumps, as fitted
Real photos, each one captioned with what it shows.
Eight checks you can make
- Is there an error code? Write it down. See the error codes.
- The pressure gauge. On the indoor unit or the cylinder. Below about 1 bar is low. Your manual gives the right pressure; don't top up a sealed system unless it tells you how.
- The controls. Is the heating on, the schedule right, holiday mode off, the room thermostat calling for heat?
- The power. Is the isolator by the outdoor unit on, and has a breaker tripped?
- The outdoor unit. Clear leaves, snow or anything blocking it. Steam and a pause in cold, damp weather is a defrost cycle, and it's normal. A unit frozen solid isn't.
- Radiators. A heat pump runs cooler than a boiler, so radiators feel warm rather than hot. Cold at the top means air in them.
- Hot water only? Check the hot water schedule and the immersion setting.
- One reset. Switch it off at the isolator for a few minutes and back on, once. If the fault comes back, book a repair.
Never open the outdoor unit or the refrigerant circuit. It's high voltage and pressurised gas.
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Questions we get asked
Why is my heat pump running but not heating?
Usually low water flow or pressure, a blocked filter, a setting, or the unit stuck in defrost. Check the gauge and the controls first.
Why are my radiators only lukewarm?
Heat pumps run at lower water temperatures than boilers, so radiators feel warm, not hot. If rooms don't reach temperature, the system needs a look.
Is it normal for steam to come off the outdoor unit?
Yes, in cold, damp weather. That's the defrost cycle melting frost off the coil.
Should I top up the pressure myself?
Only if your manual shows how and you have a filling loop. If it keeps dropping, there's a leak to find.
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