Three of the Most Common Gas Central Heating Issues (and how to fix them)

Posted on 28th February, 2018 | Posted by admin


Gas central heating issues can in the very least, be a slight annoyance. In worst cases, they can be a huge inconvenience and create lots of unforeseen expense.

Here we list three of the most common and innocuous gas central heating issues most homeowners encounter and what you can do to try and rectify them.

Important: If you can smell gas, you must call the Gas Networks Ireland 24 hour emergency line immediately on 1850 20 50 50.

When All You Want is Warmth…

But you have no hot water or heating.

  1. Ensure your mains gas supply is working by checking whether your other gas appliances such as your gas cooker or fire are operational. If these aren’t lighting then it’s most likely an issue with your mains gas and you should call your gas supplier.
  2. Does your boiler need resetting? Sounds obvious but this is something that can be overlooked. The boiler reset button is usually found on the front of most modern boilers. Turn the dial to ‘reset’ hold for three seconds, then switch back to it’s normal setting.
  3. Is the water pressure too low for the boiler to work? Check the pressure dial on your boiler: It should be set to between one and two bars. If it’s lower than one, open up the pressure valves to let more water into the system until pressure reaches the correct level.
  4. Has the pilot light gone out? If it has, or if it keeps going out, it could be a sign of dirt and debris build up in the pilot light mechanism. This can usually be rectified by poking a long, thin object into the hole in the pilot light pipe to shift the dirt. If, however, you’re unsure how to do this, then please consult your manufacturer’s handbook or a RGII engineer.

When You’re Almost There but Not Quite…

If your boiler is working and the heating has kicked in but there are cold patches on:

  1. The top of your radiator: This means there’s air in the central heating system and you’ll have to bleed your radiators to release the air and allow the radiators to fill with water.
  2. The middle of your radiator: There’s a possibility that rust and sludge are blocking the bottom of your radiator. This usually involves a power flush of the system. This is normally carried out by a RGII engineer.
  3. The bottom of your radiator: This could mean rust, sludge and limescale build up is blocking the flow of water in your radiators. You can attempt to eradicate this by using a chemical sludge remover, but this only works if you have an open-vented system. If you have a close-vented system, then it requires cleaning out by a professional Gas Registered engineer.

My Boiler is Making Loud Noises

A clunking, thudding boiler is never a nice sound, and although it’s usually a sign of something serious, you’ll be glad to hear that sometimes it can be caused by a fixable problem!

Check that:

  1. The thermostat isn’t set too high. If the water in the boiler is overheating, it could be causing the clunking noise you hear.
  2. If the thermostat is fine, there may be overheated water in the central heating system due to a build up of limescale. If you do have a limescale build up, the system will need to be flushed with a chemical flush (for open-vented systems) or by a professional (with close-vented systems).
  3. Check that enough water is getting into the system by checking your water tank levels and ensuring that your water supply hasn’t frozen.

If you carry out all of the above checks but you’re still having gas central heating issues, then it’s time to call in the experts.