Solar Thermal – Installation and Repairs

Solar Thermal Energy is one of the most popular forms of renewable energy in the UK today, and it’s not difficult to see why. As well as heating your hot water through summer and winter, you can over time recover the cost of installation through the savings you can make on your energy bills. We at Biggs Heat Technologies we have fully accredited Solar Thermal Systems Installers. For a no-obligation assessment of your property and a quotation please call us on 07887 647921 or 01202 386439.

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Solar systems should be serviced every four to five years.

Biggs Heat Technologies service and repair solar thermal systems.

Solar Service and Installation


1. Clean the collectors

2. Check Glycol quality

3. Check expansion vessel pressure

4. Check correct operation.


Stagnation occurs in solar thermal systems when the temperature in the hot water cylinder reaches the set temperature and the controller stops the pump to prevent over heating of the cylinder.

When the pump stops the glycol stops circulating and the fluid in the collectors during this period stays static in the panels. Even though the pump has stopped circulating, if solar energy is still available the panels will continue absorbing the energy which can heat the fluid in the panels to in excess of 180 degrees which makes the fluid flash to steam in the panels.

The system components are designed to withstand stagnation, but regular prolonged periods of stagnation will cause premature failure of components and the glycol.

Stagnation is normally caused by poor system design or poor user understanding of the system. Think of your Solar thermal system as your primary hot water heat source. In spring as soon as solar gains are available then turn you boiler hot water programme to off and try to rely on the Solar for hot water using the boiler as a boost if necessary.

This will prevent stagnation, maximise solar extraction and payback for the system and reduce fuel bills.

Heating the hot water cylinder on a daily programme using the boiler during summer months will mean in the morning two-thirds of the hot water cylinder will be hot from the boiler, only leaving the bottom third for the solar system to heat up. This will cause stagnation.

Adapt your hot water usage to suit the Solar system. Try to carry out most of your hot water usage in the afternoon/evening. Ideally running out of hot water at the end of the following days early morning usage will give the solar system a completely cold tank to dump its energy into all day again reducing the risk of stagnation.

Periodically check your pressure gauge. (normally found on the pumping station) If it reads zero this will indicate that the system needs servicing.

Contact Us

Contact us if you would like a quotation for a solar thermal system or a service on an existing system.

To get a FREE no-obligation quote, call Tel: 01202 386439 or Mobile: 07887 647921 now or complete our online enquiry form.