We have a Baxi boiler that keeps turning itself off. There are three lights on the front: green, amber and red. The green shows power is on and should stay lit. Amber shows it is fired up and heating water etc. The red shows it has over heated. There is a little dial to adjust temperature I guess that has always been set to about 3/4 on.

We noticed there was no hot water and looked at the boiler and the green light was flashing and the other two were off. Turned the dial off and then back on again and the green light went on permanently and the amber light turned on and we had hot water and heating… for about 10 minutes until it turned itself off and the green light started flashing again.

Any suggestions of what to do/check before we call out a heating engineer who will twiddle something and charge us £150 for 5 minutes work?

Pilot light going out?

Possibly – any ideas how to stop it going out?

You could try checking the gas supply but it might be that the pilot needs a new part – no idea what it is called, but the little thing the flame burns from.

But I would sugest the professional advice – you don’t want to be messing with gas.

I am not planning on taking anything apart. Just wondered if there was a simple trick like ‘turn it off and then on again’* which is the standard solution with PCs

*Yes, I have tried that

It has just started working again!

The part mastiles mentions is called the Thermocouple, it could be that and is quite easy to replace, you could do it yourself before you ring that expensive heating engineer 😉

Or has the water pressure dropped?

nige – Look at my name. Do you seriously expect me to be allowed near a boiler with a hammer?

Ha ha ha i was thinking that as i typed, especially now your thinking about using a hammer!!!

Of course I would use a hammer, the axe would be plain stupid!

and it has gone off again 🙁

Is it coming on and off by itself? If so it won’t be the pilot as it would go off and stay off.

COULD be water pressure.

Okay, I have had time to play with the controls here is what happens.

Turn the dial on the boiler off for about 15 minutes and then turn it back on and the boiler fires up. The green light stays on and after a couple of seconds the amber light comes on.

After about 20 minutes the boiler goes off and the green light starts flashing. The boiler won’t restart until you have turned the dial off, left it for 15 minutes and then turn it back on.

There is no banging of pipes or any funny noises from the boiler. How do I check/correct the water pressure?

Pressure usualy between 1 and 2… there will be one of the taps under the boiler to adjust this…

Have you checked the Baxi website with the model no ?
Might be a user guide online.
Is it new(ish)…sounds pretty new so unlikely to have a pilot light (& thermocouple).

Low water pressure ?
Should be about 1.5bar.
Should be gauge / display on front.
Small tap underneath that you open & fill the system with, open & wait till reaches 1.5bar.

Low gas pressure ?
Decent flame on the cooker hob ? (If gas)

Could be a few things.
Ring a local Baxi dealer, they should be able to tell you.

Sounds like there is no/little circulation of water through the boiler.

If the water isn’t getting topped up, the boiler could overheat and trip a thermal overide. Go in the loft and check the header tank ball valve has not stuck and that the tank is full up to the ball. (assuming this is a vented system). If it’s a combi, make sure you have not lost water pressure – there will be no header tank. There’s usuually a water pressure meter inside combi boilers – consult your user manual.

Also check that the circulator pump is running. Put you hand on it to feel if it is turning.

The other thing to check is if the motorized valves are opening. I don’t expect this to be a problem because it is quite comon for the switch in the valves to “call” the boiler to start up.

Let us know if you find any of these affect the problem.

You can tell if it’s a combi as it will have a pressure vessel, pumps and motorized valves all built into the boiler casing. Plumbers like combi’s coz they are less work to fit and you don’t need header tanks, pumps, MSV’s and yards of additional connecting pipework.

Get your manual online if you can’t find the original.

sounds like either the thermocouple or pcb, ours usually gets replaced at the annual service visit. Do you not have a maintenance contract?

Latest update, I have spotted a pattern.

When the boiler is doing something like heating the water in the tank or when I turn the central heating to max it stay on and is fine. As soon as it stops firing because either the water is heated or the house is up to temperature it conks out.

I wait 15 minutes with it turned off and then turn it back on and as long as the water or house need heating it works fine.

It is like it stalls on idle (yes I know that is cars and engines but you know what I mean).

Did you check the things I mentioned?

What boiler is it? Exact model number etc, gc no would be nice, but not essential

Baxi 100 HE – No Manual

The pump and valves appear fine and it works correctly when it is switched on and running. The water tank in the attic is full and the hot water and central heating both seem to work fine except when the boiler goes off obviously.

runs for a while then overheats, leave off then can be resetted?

Probably the red foam seal/or the inner door at the bottom left hand side has gone, heat escapes from there and is re-circulated by the fan, there’s an overheat stat on the fan that trips, locking the boiler out untill it cools. When your gas man comes and takes the case off, it’ll run perfectly, as the heat can’t build up.

Just to clarify, you did look at the small header tank for the central heating and not the main cold water storage tank!?

British Gas On call assistance may be some use to you, fixed fee for the job, looking around the £150 mark, no fix no fee.

Had similar problem with mine, it was a thermocoupler..i say go with British Gas and they may eventually replace the boiler for reduced cost…

Here’s an idea…try a forum like say, STW, and post an “anybody know a good plumber near [insert location]…” and see what happens. FWIW, these things are normally complicated and combi’s stop functioning for all kind of reasons, sometimes simple, sometimes bloody complicated.

Oh, and just before Christmas, I had a similar problem to yours…a new boiler, £1600 lighter and beans on toast for Crimbo dinner 😯

I’m almost certain it’s what I said above, I’ve repaired plenty of them. However it really could be owt (except the thermocouple cos there isn’t one 🙂 ), Our on call assist jobs are very popular and cracking value,

What I really want to know is…

WTF are you doing with your heating on at this time of the year?????

masty – It is the central heating AND WATER. We are showering at this time of year. The heating is incidental.

paul – looks like I will be calling them. Thanks

Any update?

He used the hammer and blew himself up…well it’s his name after all…

At least it isn’t winter 😉

FFS Worlclassaccident, stump up for a central heating engineer!

Blocked condensate syphon? Or muck from the heat exchanger stopping the pilot from lighting after one cycle. Both will require the use of an engineer as they’re on the “hot” side of the case.

When your gas man comes and takes the case off, it’ll run perfectly, as the heat can’t build up.

i’d try that. try not to loose any screws.

Still alive? I’d leave taking it to bits to a gas man

Took the front of the boiler, swore at it, decided it looked a bit dangerous for me to play with so put the case back on. Just walking to the phone to call an engineer when the boiler fired up. It has worked fine since then.

Conclusion – Swearing fixed the boiler.

thats my technique too