Protecting your heating systems if your supply fails
Different types of heating system need looking after in different ways in the event of a water supply failure. Check what type of system you have and follow the advice below.
Any heating system with a cold water storage tank and hot water cylinder
If you have a heating system which uses a cold water storage tank (usually in the attic) and if the water supply is cut off, but your cold water storage tank is full, it’s safe to run your central heating. However, you should not use your hot water. A system with a cold water storage tank may give a limited amount of hot water after the supply is cut off, but you risk running the storage tank dry. If that happens it will create an airlock when the water comes back on again, so don’t be tempted.
If your cold water storage tank has run dry, do not use your central heating or your hot water as this could cause your hot water cylinder to collapse.
If you have a combi boiler (where your hot water is heated directly form the gas boiler and you don’t have a hot water cylinder) you can use your heating, but you must not use any hot water from the taps.
If you have Economy 7, turn the immersion heaters off.
Solid fuel/ oil central heating system
If you have a back boiler on your fire (i.e. if your fire heats water or radiators in your home) do not light your fire while the water is off. Once the water supply has been restored, light only a small first at first.
If you are unsure of anything at any time contact a qualified heating engineer