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Low boiler pressure
Low boiler pressure
Usually displayed on the boiler's built-in pressure gauge, check that your boiler pressure is not too low. If your boiler pressure is below 1, your central heating system is likely not able to function properly. Low pressure can be a result of various potential reasons, such as a water leak in the system, the pressure relief valve needs replacing or a cause of recently bleeding the radiators. A simple first step you can take is to look for a visible leak in the system. If a leak is found, try re-pressurising your boiler via the filling loop on a sealed system.©
Radiators not heating up
Radiators not heating up
Cold patches in radiators is a common problem and is often due to the build-up of sludge or air trapped inside the system causing an unequal distribution of heat. The resolution will depend on whether the cold patch is at the top, middle or bottom of your radiator. For example, if only the bottom of your radiator is getting hot then there is most likely trapped air and you'll need to bleed the radiator. A cold patch in the middle or at the bottom of your radiator is usually caused by a build-up of sludge and rust., as shown in the image above. This can be overcome by flushing the system out or removing the radiators individually and flushing the affected ones.
Frozen condensate pipe
Frozen condensate pipe
Motorised valve parts
Motorised valve parts
The motor that drives the valve into open and closed positions.
Other common faults (not an exhaustive list)
Other common faults (not an exhaustive list)
If there’s no central heating or hot water
If there’s no central heating or hot water
Check that the central heating programmer is set to “on”. It may have been turned off in error.
Check that the thermostats are turned up to the correct level.
Check that the electricity supply is switched on and that the central heating fuse has not blown. If both are fine but the programmer is not receiving power, there may be a loose connection. Call an electrician to check the wiring.
If a motorised valve is fitted (to control the flow of hot water from the boiler), slide the manual lever to open it. If there is resistance, the valve is not opening properly. This could indicate a burnt-out motor.
If the pump isn’t working, you can try to start it manually.Turn off the central-heating system and wait until the pump is cold. Remove the screw in the middle of the pump and turn the impeller (the pump's manual starter). On some models, this is a small screw that is turned with a screwdriver. On others, there is a small handle attached. If this doesn’t work, try tapping the pump casing sharply, but gently, with a mallet 2 or 3 times, or remove the pump, and flush clean water through it with a hosepipe. Do not submerge it in water. If none of this works, replace the pump.
If the pump is running, but the boiler does not light, check that the pilot light is on and that the gas supply is turned on at the meter. If you have an oil boiler, check that the fuel is turned on and that there is oil in the tank. If the pilot light is off, follow the procedure in the handbook or on the boiler casing to relight it. If it will not stay lit, the flame failure device probably needs renewing.
If a combination boiler will not light, check on the pressure gauge that the water pressure is at least 1 bar. If it is above this,If it is below, top up the water via the mains filling point.
If the mains pressure to the entire house has dropped(check by running the taps), call your water supply company for advice.
If the central heating is working but there is no hot water
If the central heating is working but there is no hot water
Make sure that the thermostat on the hot-water cylinder is set to 60°C.
Check that the motorised valve (if fitted) to the cylinder is open.
Bleed the air-release valve beside the hot-water cylinder (if there is one). The valve is usually located on the pipe that enters the heating coil.
If the upstairs radiators are hot but downstairs radiators are cold
If the upstairs radiators are hot but downstairs radiators are cold
This is probably due to a jammed pump.
If the downstairs radiators are hot but upstairs ones are cold
If the downstairs radiators are hot but upstairs ones are cold
Check that there is water in the feed-and-expansion cistern.If it is empty, the ball valve has probably jammed.
Bleed the air from the system.
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