How does an anti gravity valve help me save money on my central heating?

What is an anti gravity valve?

An anti gravity valve is a non return valve which works to prevent thermosiphoning.  They are fitted vertically onto the flow pipe for the central heating above the boiler. They are used to stop water from thermosiphoning into the radiators when the hot water is called.

Anti Gravity Valve

Anti Gravity Valve

How does an anti gravity valve save me money on my central heating?

If you do not have an anti gravity valve, your radiators will be heated when you do not need them to. This wastes energy and increases the cost of your heating bills. Anti gravity valves can save you money on your central heating. This is because they stop the flow of hot water to the radiators when the heating is off. This stops the boiler from having to heat more water to replace that which would be lost or wasted when it is thermosiphoned to the radiators.

How does an anti gravity valve work?

Under low pressure, the weighted or spring loaded flap inside the valve will close when circulation stops in the circuit. This is so that water cannot pass through the wrong way. When circulation of hot water for heating is needed, the power of the water pump causes the flap inside the anti gravity valve to open in order to allow water to flow through to the radiators.

Anti gravity valve diagram

Anti gravity valve diagram

What happens if the anti gravity valve is not working?

If the anti gravity valve needs replacing there can often be excessive amounts of air in the radiators. If the valve gets stuck open, the radiators will get hot when only the hot water is switched on. If the valve gets clogged up or stuck shut, then the water will not be able to circulate to the radiators when the heating is on.




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