Wiltshire Energy

Summer care for your heating

Summer care for your heating

Summer care for your heating system


During the summer, your heating system can remain idle for many months. You may not know it, but damage is being done the inside of your radiators in the form of corrosion. If the pH balance is too low, then the steel parts of your heating are being eaten away and may spring a leak in the future.

Regular annual maintenance by a suitably qualified and experienced heating engineer will identify issues within the water circuit. Flushing or chemical treatment can alleviate problems before they occur.

  • The ideal pH of a heating system is 7.6 to 8.4.
  • Low pH will cause acidic corrosion
  • High pH will cause scale to form, blocking pipes and valves
  • If you have an air source heat pump, then the frost protection (glycol) level should be maintained to between -12°C and -18°C.
  • A magnetic filter will help reduce deposits (ferrous) from clogging up the heating system

Thermostatic Radiator Valves (TRVs)

Thermostatic Radiator Valves or TRVs control the room temperature using a self acting actuator, located on the valve body. During summer, the room temperature can we above the set point of the TRV and the valve will be forced closed.

If the valve is left in the closed position, it could have to tendency to stick closed and not work when you turn the heating on at the end of Autumn.

To prevent this from happening, it is best to leave all the TRVs in your home in the fully open position, and turn off the heating on the controller.

If the valve has stuck closed, then it is possible to free it up by gently tapping the pin, when free, it will pop up by about 3mm.


Heating pumps can also size in the summer due to inactivity. Older style “induction” pumps attract magnetite (magnetic ferrous sludge) around the pump rotor and lock up. This can be prevented by periodically running the heating on minimum for about 10 minutes.

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