First Checks — No Heating or Hot Water
Run through these four checks before anything else if your heat pump isn't providing heating or hot water, or isn't turning on.
1. Check the thermostat
- Make sure it's set to 'Heat' or 'Auto' mode.
- The target temperature should be set a few degrees above the current room temperature.
- If the thermostat runs on batteries, replace them.
- Check the timer or schedule hasn't been accidentally changed.
2. Check the power
- At your consumer unit (fuse box), check whether the switch labelled 'Heat Pump' (or similar) has tripped. If it has, try resetting it once. If it trips again immediately, leave it and call an engineer.
- Check the external isolator switch near the outdoor unit (usually a large red switch on an outside wall) is in the ON position.
3. Check the outdoor unit
- Clear any leaves, twigs, snow, or garden furniture that could be blocking airflow. The unit needs at least two feet of clear space around it.
Annual Servicing
Having your heat pump serviced once a year is the easiest way to protect its lifespan. It's also a requirement of your guarantee terms and ensures the system runs at full efficiency. If your housing provider has a maintenance contract with Correct Contract Services, you don't need to worry. We will contact you to arrange a service and make sure that your system is running efficiently.
The Outdoor Unit in Cold Weather
If the outdoor unit is iced over or covered in snow, this is completely normal. Heat pumps are tested in extreme conditions — including temperatures as low as -25°C — and are built to operate reliably in cold British winters.
The defrost cycle — In cold weather, a thin layer of frost on the outdoor unit is expected. The system will automatically run a short defrost cycle every so often to clear it. During this time, the fan will stop and you may hear a hissing sound or see steam coming from the unit. This is normal and typically lasts 5–10 minutes.
Insulating any exposed pipework around the outdoor unit can help reduce energy use, particularly in winter.
How to Reset Your Heat Pump
When to do this: If the system is unresponsive, showing a non-critical error code, or has been through a power cut. A reset often resolves minor software issues.
Before resetting, note down or photograph any error code displayed. If the reset doesn't fix the problem, your engineer will need it.
Steps:
- Locate the circuit breaker for the heat pump in your consumer unit, and the external isolator switch near the outdoor unit.
- Turn off the power at both switches.
- Leave the system off for at least 15 minutes to allow the electronics to fully discharge.
- Turn the isolator switch back on first, then the circuit breaker.
- The system will take a few minutes to restart. Check the control panel to confirm the error has cleared.
Understanding Your Heat Pump System
Heating
Your air source heat pump heats the home and hot water cylinder in a similar way to a gas or oil boiler, but with a few important differences.
CCS will have fitted a room thermostat and Thermostatic Radiator Valves (TRVs) on each radiator, giving you full control over your heating. The heat pump responds to signals from the room thermostat.
When the system first starts up, it will take a little time to reach temperature, but you should feel the radiators beginning to warm within 10 minutes. It may take a few days to settle at the right temperature throughout the home. Don't switch the thermostats off during this period.
Radiator temperatures will be lower than with a gas boiler. The system runs in weather compensation mode, automatically adjusting radiator temperature based on how cold it is outside, warmer radiators when it's colder, cooler when it's milder. This is automatic and helps keep running costs down. In very cold weather, radiators can reach up to 50°C.
Running Your Heating Efficiently
Heating a cold home from scratch is slow and expensive. The most efficient way to run a heat pump is to keep the home at a steady temperature around the clock. Leave it on 24/7 at a constant setting rather than turning it off and on.
When you go out, don't drop the temperature by more than 2°C below your normal setting. A bigger drop takes a long time and a lot of energy to recover from.
To effectively turn off the heating in summer without switching off the system, set the room thermostats down to 17–18°C. The heating won't activate at those settings.
Hot Water
The system maintains your hot water between 45°C and 50°C at all times, constantly topping up the cylinder as you use it. Hot water takes priority over heating. If the cylinder drops 5°C below its target temperature, the system will automatically switch to heating the water first. This usually takes less than an hour, after which it returns to heating the home.
The hot water cylinder is well insulated and retains heat efficiently.
Legionella cycle
The system includes an automatic disinfection cycle that heats the cylinder to 60°C using the immersion heater. If this cycle fails to complete, an error code will appear on screen, and you'll need to call an engineer.
Room Thermostat
The thermostat monitors air temperature and switches the heating on and off accordingly. Set it to the lowest temperature you're comfortable with, and leave it to do its job.
