Central heating problems and solutions

If your house feels like an iceberg or there’s only frigid water pouring from your taps, there are some useful checks that could save you a call-out fee, or help you to give an engineer information about the nature of the problem.

Trouble Shooting for your central heating problems

Listed here are the most common problems which can occur with central heating systems and some quick fixes, solutions and useful tips that will have it up and running, and you and your family lovely and warm once again.

Read more: Troubleshoot your boiler problems


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. Call a heating engineer.
  • 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. Call a central heating engineer. 
  • If a combination boiler will not light, check on the pressure gauge that the water pressure is at least 0.5 bar. If it is above this, call a central heating engineer. 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

  • 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

  • This is probably due to a jammed pump.


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


Boiler still not working?

Boiler brands like Worcester Bosch, Baxi and Glowworm have varying warranty lengths on items such as pumps. So check the manufacturer T&C's to see if your boiler is still under warranty. "