Tips & Advice for Owning & Maintaining Your Heat Pump

These tips can help to prevent problems occurring with your heat pump and prevent possible damage to the unit and also reduce your running costs to the minimum.

  1. Avoid placing items such as bins, plants, dog kennels, water tanks etc, or parking vehicles within 1-meter either side of the outdoor heat pump and 1.5 meters in front of the heat pump unit, as this will disturb airflow and result in the heat pump working harder causing higher electric bills.
  2. Do not place screens or fences, hedging, shrubs, or plants around the heat pump as this will reduce the airflow which will increase the running costs. Placing plants close to the outdoor unit can attract  snails which can enter the unit and can cause extensive damage to electronic PCB boards resulting in costly repairs.
  3. Keep the heat pump clear of leaves and debris under and behind the outdoor unit. Leaves can be drawn in by the fan and block the airflow through the coil fins causing restricted airflow and can also cause blockage of the water drain on the bottom tray.
  4. Do not power wash the outdoor unit as power washers cause expensive damage to the coil fins reducing your heat pump efficiency and increasing running costs.
  5. During domestic hot water heating (DHW), the heat pump stops heating the radiators and the under-floor heating until the domestic hot water reaches its target temperature as set on your controller. When the DHW target temperature is reached plus 2 degrees it will then return back to heating your radiators and underfloor heating (Priority goes to heating the DHW). This is why your radiators may feel colder when the room stat is calling for heat.
  6. Avoid using the timer function to heat the rooms (unless you have reduced night rates), heat pumps are most efficient in constant mode rather than in timer mode.
  7. Avoid placing cover screening panels on your radiators as they restrict heat emitting from the radiators causing the heat pump to run longer to reach the room target temperature.
  8. Avoid placing items such as coat hangers close to the heat pump isolation switch in the hot press, as there is a possibility of inadvertently knocking off the isolation switch, which can occur when hanging coats etc. this will result in the heat pump shutting down, and you may not be aware of this for several hours or days later.
  9. Avoid open windows and doors as heat losses will occur causing the room temperature to drop resulting in the heat pump running excessively to maintain the target temperature called by the room stats.
  10. Reduce (DHW) domestic hot water temperatures to the minimum temperature which will minimize running costs. The typical domestic hot water temperature found on most heat pumps is 48 degrees, every degree below this will reduce your energy costs.
  11. Ensure your heat pump is serviced once every year as this service is part of a preventive maintenance program and a requirement to keep your heat pump warranty valid and also reduces the possibility of a heat pump shutdown.
  12. Apart from the DHW temperature, avoid changing any of the other settings that were set during the commissioning of the heat pump.
  13.  When cutting the grass, ensure that the grass cuttings don’t enter the fan grill, which can lead to blocked drains.
  14.  Blocked drains can lead to the accumulation of water in the lower area of the case during the defrost cycle which can freeze in wintery  conditions, this build-up of ice can cause the fan blade damage when the blade hits the ice build-up,


Heat pumps are controlled by the end user via the wall-mounted room stats. The room stats are basically a switch for turning on and off your heat pump system.

Comfort levels are increased or decreased by the room stat by increasing or decreasing the temperature by the up arrow or the down arrow or by a rotary dial in some cases.

After increasing the required room temperature, a flame should appear on the stat screen which sends a run signal to your heat pump provided the required temperature is above the current room temperature.

When the room stat reaches the set temperature, the stat flame on the screen will disappear and the run signal to the heat pump will distinguish and the heat pump will stop running. When the room drops approximately 1 to 2 degrees below the pre-set temperature, the stat will re-call for the heat pump to run until that pre-set target temperature is reached maintaining the room to your set comfort level.

For a 2 or 3-story house, a room stat for each floor level works best with heat pumps, as heat pumps don’t run economically with constant start and stop cycles which can occur with units that don’t have a buffer tank installed. Room stats in every room can lead to excessive heat pump start cycles causing higher running costs. If you have stats fitted in all rooms, setting them to the same temperature will reduce excessive heat pump start-stop cycles which keep your running costs down. With the exception of bungalows where bedroom stats may be needed for lower temperatures for comfort levels.

Heat pumps should be left on all the year including Summer and Holidays. Reduced temperatures on the room stats for the summer will keep the heat pump on standby for the heat emitters and the pump will only operate for the heating of the domestic hot water.

If you are going on holiday during the winter, room temperatures may be reduced by 1 to 2 degrees which will prevent the house from cold soaking which will lead to costly electricity bills on your return when bringing back up the temperature in your home to your comfort levels. Using this method there is no need to use the holiday mode option on your remote controller.

Room stats showing a padlock symbol on the screen indicates that the screen is locked, and no temperate adjustments are allowable. In most cases pressing and holding both the up and down arrows at the same time for 5 seconds will disable the lock allowing temperature change.

The location of the room stats is important for accurate room temperatures, preferably not in direct sunlight or close to exterior doors which can cause an inaccurate temperature reading and can result in inaccurate room temperatures.

Water Operating Temperatures

Domestic hot water (DHW) can  be set as low as 41 degrees (which will not give give you shower hot water 24  x 7 x 365 hot water, set to 48 degrees if you need hot water for a shower 24  x 7 x 365) and set flow temperatures for radiators at 45 degrees, underfloor heating flow temperature can be set lower to 35 to 40 degrees due to underfloor heating being more efficient than radiators.

It is good practice to lower your domestic hot water to 41 degrees, scalding can occur at 45 degrees, decreasing it to 41 degrees can prevent the possibility of accidental scalding and will also reduce your electricity bill.

Heat Pump Warranty

Your heat pump requires a service every year to keep your warranty valid under the Manufacturer / Distributor warranty terms and conditions.

An annual service also keeps your heat pump running most efficiently saving you on your electricity bill and reducing wear and tear on your Heat Pump system.

Only an approved service Engineer trained by the heat pump Manufacturer / Distributor is acceptable to service your heat pump under your warranty terms and conditions.

Servicing it yourself or having it serviced by someone who is not trained and approved by the manufacturer/distributor will void your warranty.

Keeping your warranty valid is of the utmost importance to you, as it will minimize expensive repairs plus costly call-out fees, and less worries to you in the event of a heat pump failure.

A warranty call receives a faster response call-out time and it saves you the time and stress of looking for an Engineer to repair your heat pump, especially in the depth of winter when you most need your heating system working, bearing in mind that heat pump Engineers are not always available for breakdown call outs at short notice.

Warranty time varies with heat pump Manufactures, some last up to 10 years. Your heat pump is registered for its warranty at the time of commissioning and your annual service records keep your warranty valid.

The Outdoor Unit Drainage Tube Cleaning

One important item that is sometimes overlooked, is the inspection and cleaning of the outdoor unit drain tube. It is vital that it is kept clean and free of leaves and sludge build-up to allow the free flow of the condensate water from the base tray. When the drain tube is blocked it will cause water accumulation on the bottom of the base tray which will lead to the onslaught of corrosion resulting in the base tray decaying and losing its integrity. Some of the components such as the Compressor are mounted on the base tray. Heavy corrosion in this area can cause the compressor to shift and lead to extensive damage to the outdoor unit over time. Blocked drains can also cause the water to freeze in winter leading to fan blade damage. Part of the annual service is to inspect and clean the drain to ensure that this drain tube is unrestricted.

Electricity Supply Interruption

If you receive notification from your electricity supplier regarding a planned outage due to maintenance etc, it would be good practice to power down your heat pump in advance of the outage. As some heat pumps can have fault alarms arising after the power is restored.

Guidance on having a Heat Pump installed

Step 1   Have a heat assessment carried out on the house, this will determine if your house is suitable for a heat pump to efficiently heat your home. If your house is not suitable for a heat pump, you will be advised on what upgrades are necessary to make your home suitable for a heat pump. This may be in the form of replacement radiators, additional radiators, additional insulations, upgraded windows and doors, external insulation, ventilation recovery. Heat pumps work most efficiently on homes with a BER A rating.

Step 2   Design stage, this is where the information from the heating assessment is passed on to the design team who will determine the KW size of the heat pump, radiator type, and size, and the underfloor loop design, etc. You should consider the use of a buffer tank, as a buffer tank works more efficiently with a heat pump and helps keep operating costs down.

Step 3 The location of the room stats is of the utmost importance and commonly over looked. The height from the floor, the distance from the radiators and not above a radiator, not in direct sunlight, not located at the front or back door, etc. The type of wall stat being installed, smart stats give the end user more information such as current room temperature and target room temperature, and running information such as whether the room stat is calling for heat or not. If one wall stat is being installed for the upstairs zone, avoid placing it in a it in one of the bedrooms , place it in the landing area.

 Step 4   The installation stage is extremely important, such as the location of the outdoor unit, ensure you discuss well in advance of the installation day as having it relocated is expensive to carry out. Avoid facing the out door unit into prevailing winds and also if possible avoid placing the unit on the north side of the building. Ensure the distance between the heat pump from the wall and the clearance from the side of the unit and in front of the unit are adhered to, typically 300 mm at the rear 1.5 meters at the front, and 1 meter at the sides. The isolation switch should not be mounted on the case of the outdoor unit. Avoid locating the unit close to the bedrooms. Avoid mounting the unit on the wall of your house as running noise can transmit into your house, When mounting on wall brackets, consider using a drip tray as this will prevent the runoff water from dripping to the ground which can lead to icy slip hazards in the winter. Also, avoid mounting the unit high off the ground as this can lead to higher maintenance costs due to access and having to use ladders and platforms etc.

The installation information is clearly laid out in the booklet that is supplied with the heat pump. If these instructions are not adhered to, it can result in failing the commissioning of the heat pump and cause high running costs on your heat pump.

Step 5   The final stage is the commissioning stage, this is where the heat pump supplier sends out an Engineer to set up the heat pump running parameters such as temperatures, and flow rates, and also carries out operational tests to ensure the heat pump is running correctly and finally registers your heat pump for warranty. Remember an annual heat pump service is required to keep that warranty valid.

Use of Timers and Schedules

It is not recommended to use timers and schedules with air-to-water heat pumps for the following reasons. Heat pumps are unlike gas and oil systems where the radiators can achieve very high water temperatures of up to 75 degrees Celsius which will result in a rapid response in radiator heat output leading to very quick heat-up times in the rooms. A timer and schedule work well with this type of high-temperature heating system.

On the other hand, an air-to-water heat pump heats the house with a low-temperature system, heating the underfloor and radiator water between 30 and 45 degrees Celsius. This is only warm water compared to the 75-degree hot water used in the above systems. The low-temperature water used in the heat pump system takes a long time to heat the rooms to reach its target room temperature set by the end-user on the room stat, when it reaches its typical temperature room temperature of 21 degrees downstairs and 19 degrees upstairs the heat pump stops and it goes off until the room stats drop by 1 degree in which and it will then kick back in and run until it returns to its target temperature. Essentially all it is doing for the remaining of the winter is maintaining the room target temperature set by the end user on the room stat.

The heat pump runs for long periods at low temperatures and low costs compared to the oil and gas running at high temperatures for short periods.

If a timer or schedule is set on the heat pump system, it will inhibit and prevent the heat pump from maintaining the 1-degree differential temperature drop set on the room stat and will lead to the heat pump working harder and struggling to reach the set target temperature leading to higher electric bills and a colder home.

It is important to note that the heat pump is much different from oil and gas and therefore should not be run in the same manner, as it’s a low temperature with slow response time and when used correctly in a suitable house will result in a more comfortable home with lower running costs.

The heat pump should not have several temperature changes such as lowering and increasing it during the day, due to its slow response time this will result in higher running costs. It’s a set-and-forget system. Set it to your comfortable room temperature for the winter typical temperature of 21 degrees and reduce it to 12 degrees in the summer to prevent it from coming on.