Gas combi boiler increasing pressure & switching off

[mrsh]

Hi all - the original problem was a combination of the water pressure decreasing sometimes and increasing other times, both resulting in the boiler making a 'click' sound & the pilot light going out within an hour or so.

We have bled all radiators and cannot see any visible signs of leaking at the boiler or any of the radiators. We suspect the increasing pressure problem may be caused by a blockage in the system somewhere in the boiler or a radiator(s).

A plumber cleaned out the system & fitted an inhibitor to prevent the system from clogging up in future, however...

Now the boiler runs normally at about 1 bar of pressure, with the pilot light lit & hot water flowing fine. When the central heating is switched on, the pilot light flame increases as usual & the radiators begin to warm-up. The water pressure increases gradually to 2 bar after 10-15 mins, the boiler makes a 'click' sound & the pilot light goes out which has the knock-on effect of no hot water (obviously). So we have to re-ignite the pilot light to get the hot water working again, but the cycle begins again if we switch on the central heating. Also, even when the pilot light is lit as normal, there sometimes is no hot water. On closer inspection, we notice that although the pilot light is on, it's not fully lit to heat the water running out of the tap.

Before we consider getting another plumber out, can anyone offer any advice on this please?

It's a Glow Worm Compact 80p Fanned Flue Combi boiler with Honeywell gas control (about 10 years old).

Thanks
Scott

 

[Puddle]

You do not give make or model of boiler, what is it, but would say maybe heating thermostat out of calibration/broken, causing over heating, or could be pump over run

 

[mrsh]

Thanks for the quick reply, puddle. It's a Glow Worm Compact 80p Fanned Flue Combi boiler with Honeywell gas control (about 10 years old). To my knowledge, there is no separate thermostat as such so it must be built-in to the boiler? I'd hoped the plumber who recently visited would have found it. Do you know how much it would roughly cost to repair/replace the thermostat and/or pump if needs be please?

 

[Puddle]

The thermostat/thermistor is in the boiler,there is also adjustment on the main pcb I think if I remember correctly,anyway maybe get gas plumber to replace heating thermistor and check gas pressures through gas valve,making sure low flame is not to high

 

[fuzzy]

has anyone checked the pressure vessel?

 

[Puddle]

expansions ok,only going up to 2 bar

 

[mrsh]

Thanks for the reply. It has been suggested elsewhere that it maybe the "overheat stat". How much would it cost a plumber to replace the parts concerned please?

Another plumber visited today and said our boiler was dangerous because it could be leaking carbon-monocide, condemned the boiler & disconnected the gas supply to the boiler. He said if we didn't let him do this, he would report us to the authorities (gas board?) & they would disconnect our gas supply from outside. He said we need a new boiler, quickly produced a quote of £1750 & is pressuring us into committing to a Saturday installation by lunchtime today (Tues).

Is this acceptable or are we being paranoid to think he's a pushy saleman?

 

[cr0ft]

I think a healthy dose of paranoia is a good thing! Why don't you phone another gas fitter and get a second opinion - you may have to pay for it but it could be the best call-out fee you've ever paid. This said, it would be desperate tactics indeed if the gas fitter is lying to get a sale.

 

[mrsh]

Agreed.

I have called British Gas and am weighing up their 2 options:-
1) £99 repair + £20 p/month (12 month contract)
2) £69 0-30mins repair / £189 30-120mins repair / £349 120+mins repair (one-off repair fee tarrifs)

I think it's better value to go for option 1 because it's the same price (£349) as the one-off fee if the repair takes over 2hrs but the monthly policy also covers the 'full central heating system', not just the boiler for 12 months. Oh, and if they cannot repair then it won't cost a penny because of their "no fix, no fee" policy.

Sounds like a good deal?

 

[cr0ft]

Personally at those prices I would try to find a local gas fitter as they will most likely undercut British Gas. They won't offer you a 12 month contract but if your boiler is serviced properly you shouldn't need one. By this I also mean your heating circuit which should have fresh clear water in it, not the muck that I normally see in heating systems connected to combis!

Combi boilers generally work a treat as long as the water flowing through them is clean and full of inhibitor.

Most gas fitters will come out for free to quote for the work, get a couple out to give you an accurate idea of what is wrong and get some prices from them first.

Alternatively, if you phone the boiler manufacturer some of them keep lists of approved fitters. That's another option and you may get better results than any old gas fitter who may not be that familiar with your model of boiler.

Just my 2p.

 

[mrsh]

British Gas replaced the "overheat stat" and "thermistor" last Thursday and our boiler has been working flawlessly for over a week now. All included in the £99 fee. Yes, we also pay £20 p/month to get this deal, but we think it's worth it for the peace of mind. We think this price plan works both for us, the customer, and British Gas so it's in their interest to fix the boiler as quick as possible, which is exactly what they did. BIG thanks and thumbs up to British Gas!!

I hope this personal account helps others in a similar situation avoid plumbers who aren't skilled enough to diagnose the problem and other plumbers who inaccurately "condemn" a boiler just to rip off folk, a.k.a. cowboys!

Thanks to all who replied and helped us on our quest to repair our, otherwise, perfectly functioning boiler.
Scott

 

[SafeGasInstall]

Yes mate , Big up British Gas !

What makes thousands of customers living the good B G ????