9 Reasons Why Your Boiler is Not Firing Up for Central Heating and Hot Water

It usually happens first thing in the morning. A blood-curdling scream from the bathroom tells you somebody’s turned on the shower and found out the hot water – isn’t.

However, before you phone us asking ‘why is my boiler not firing up?’ and requesting an emergency gas safe engineer, there are a number of things you can check, and often remedy the situation yourself.


Things to check when the boiler looks dead.

It’s not as unusual as you might think, for the power to the boiler to be accidentally switched off. Especially if you have inquisitive little-people in the household. Check the boiler hasn’t been unplugged, and the switch is in the ‘on’ position at the wall socket and isolation switch. Make sure the breaker in your main fuse box hasn’t tripped. A night time power surge may be enough to do that. Push the breaker back up and see if power comes back on. If everything seems okay, hold the reset button down for ten seconds, and wait to see if the boiler reignites.


Reduced or no gas supply.

Not much we can do about this one. Have you fallen behind on your energy payments? Do you have a problem with your bank? Have you just moved into a new property, and unknowingly been left with unpaid energy bills by the previous tenant?

Energy suppliers appreciate the difficulties thousands of people are suffering in the current situation, and have various ways they can help, such as changing to prepayment meters to help with budgeting.


Are you using a portable heater?

There are a number of reasons you may find your boiler not firing up, even though the house temperature seems to be dropping. Have you had a power cut during the night? Your central heating timer may have reverted to factory settings and needs to be reset to your preferences.

Has the thermostat accidentally been turned down by those inquiring little fingers? Are you using a portable heater or clothes dryer? If it is underneath the central heating or room thermostat, the thermostat will be affected by the extra heat, and tell the boiler to shut down. Solution, move the heater or dryer. Quick check. If the thermostat is set at 20°, turn it up to 25° and see if the boiler kicks in.


Boiler working but rads cold.

The first things to check in this situation are the radiators. A system continuously working, trying to lift the temperature to that set on the thermostats, is going to result in excessively high energy bills if the problem isn’t remedied.

If your rads are warm at the bottom and cold higher up, the chances are you have an air bubble on one of the bends. Or if it’s an old system, the pipework could be getting blocked by sludge and sediment.


Bleed the radiators.

Bleeding each radiator is an easy enough job if you have a little DIY savvy and a few tools. If you’re not 100% sure where the bleed valve is on your radiators, do a little Google search. Slacken the valve and you should hear the air hissing out, followed by a dribble of water. Tighten the valve and keep your hand on the top of the radiator to see if it begins to warm up. Repeat on each radiator in the system.


Flush the system.

If the problem is sludge, we suggest you have a word with one of our heating and plumbing engineers. They carry all the necessary pipework, pumps, and chemical cleaners to power flush your system quickly and effectively, to bring it back to maximum efficiency.


A frozen condensate pipe.

The condensate pipe is the small pipe that runs through the wall to the outside of your property and carries away the boiler condensation. If outside temperatures are below freezing the water can freeze, blocking the pipe and shutting down the boiler. The solution, apply heat to melt the ice and then lag the pipe.


Operating pressure is too high or too low.

A boiler not firing up can often be caused by too high or too low operating pressure. Your boiler’s operating manual will tell you the optimum operating pressure for your boiler, and this pressure can rise or drop for a number of reasons. If the pressure is too high, the remedy is to bleed water off from one of the radiators until the pressure drops. If too low, you can open the transfer valve to add water to the system and increase the pressure.


Pilot light failure.

If the pilot light refuses to stay on it is usually a flame failure or a faulty boiler burner. Unfortunately in this situation, you will need to contact us, and one of our gas safe engineers will visit to ascertain the problem, and clean or replace the failing part.

If you have problems with your boiler not firing up, or any concerns regarding your heating system, please contact us and have a chat with one of our fully registered gas safe engineers.

T: 0131 444 2200