No heating or hot water? What to check first

Don't touch electrical switches, put out any flames, open doors and windows, and turn off the gas at the meter if you can. Then call the Gas Networks Ireland 24-hour emergency line on 1800 20 50 50 from outside the house. Don't try to fix anything yourself.

Is there power to the boiler, and is its switch on? Has the timer or smart thermostat been changed, or has the clock reset after a power cut? Turn the room thermostat up a few degrees to see whether the boiler fires.

On gas, check that other gas appliances work and, on a prepay meter, that there's credit. On oil, check the tank gauge or dip the tank: a boiler that has run out of oil often needs a technician to bleed the fuel line before it will start again.

Most modern boilers are sealed systems with a pressure gauge on the front. With the heating cold it usually sits around 1 to 1.5 bar; your boiler's manual gives the exact figure. If it has dropped close to zero, the boiler may stop and show a fault.

Many boilers can be topped up with the filling loop, following the manual. If the pressure keeps dropping, there's a leak somewhere in the system or a fault in the boiler, and that needs a plumber.

Condensing boilers drain water through a plastic condensate pipe, which often runs outside to a drain. In a hard frost it can freeze, and the boiler stops, sometimes with a gurgling noise.

If you can reach it safely, pour warm (not boiling) water along the outside section of the pipe to thaw it, then reset the boiler as the manual describes. If it keeps freezing, a plumber can reroute or insulate it.

If the boiler shows a fault you can't clear, keeps stopping, leaks, bangs loudly, or you see soot or scorch marks, stop using it and call a plumber. Only a Registered Gas Installer (RGI) may work on a gas appliance; oil boilers should be serviced and repaired by a trained oil technician, many of them OFTEC-registered.

Never take the casing off a boiler yourself.