Central Heating Troubleshooting

Troubleshooting checklist

There could be a number of reasons why your central heating or hot water isn't working. You can fix several problems yourself, avoiding a callout and - if you're a HomeCare® customer - possibly saving you money. Try these tips first:

• check the gas, electrical and water supplies to the appliance are turned on. It's surprising how easily they can get accidentally switched off
• check the thermostat is turned up and the clock timer is on
• some boilers have a pressure gauge showing system water pressure, this usually needs to be at around 1 bar, read more about system pressure
• got a system with a permanent pilot light? Check that it hasn't gone out - this is a very common problem with older appliances
• try putting your heating on maximum for a short while to see if you can get it back into action
• have the clocks gone forward or back? Your clock programmer might just need adjusting to the right time
• has there been a power cut recently? Your heating clock programmer may have returned to its factory settings when the power came back on. Test the central heating by setting it to come on in 15 minutes time - if that works, simply re-enter your preferred settings
• do you have a customer-operated reset switch (not one that needs you to remove any casing)? These are usually found on the front of modern boilers: check your user manual to see if it needs resetting
• try turning the electrical supply to the boiler off and on - the switch is usually near the boiler or in the airing cupboard. This might reset your boiler and resolve the problem
• could you have frozen pipes? In periods of long, cold weather, the condensate pipe of your boiler can freeze. See my pipes have frozen
• are other gas appliances affected? If so the problem is bigger and you need to Book a callout

For open vented system boilers 
(You have this type of boiler if it has a small black tank. You'll usually find these in the loft.)

Has the ball valve float in the feed and expansion cistern got stuck?
(this is usually a small plastic or steel tank situated in the loft)

If so, when your water system falls to a certain point, system water can't circulate. If you can safely and easily get into and move around your loft, check to see if the ball valve is stuck (usually indicated by no or low water in the cistern). Gently move the ball float valve arm to free it - do not use force. This may solve the problem.

For sealed system boilers or combination boilers 
(You have this type of boiler if it doesn't have a cistern that looks like a smaller version of your cold water cistern.)

• has the system pressure dropped? This is sometimes caused by water leaks, and can stop the boiler from working properly: 
  
  

  1. check the pressure gauge - this should be set at 1 bar. A red indicator needle sometimes shows the position set when the boiler was installed.

  2. look in your user manual to see if you can re-pressurise the boiler yourself - you can also find instructions on the rear of the control panel. But if your boiler panel needs tools to remove it, do NOT touch it: Book a callout instead.