baxi bermuda 552?

Had this problem where the pilot light goes out after around 20 minutes, wasted £50 for a gas engineer to change the thermocouple still the same.
Called him back he then said the Gas Valve unit had gone which was not the case as they generally don't go faulty.
I downloaded & studied the service manual & did the job myself in the end.
This is the way to make sure you cure this problem:
Fit a direct replacement thermocouple or equivalent not the universal type, take the pilot feed pipe loose and blow both ends to clear debris in the pipe, replace the injector pilot jet as it becomes damaged over many years of use.
After all that check the pilot flame.
The pilot flame ideally should be bluish without a yellow tip & approximately 1 inch (25mm) long, the pilot light should also be approximately lapping around the last 10mm of the thermocouple.
You will probably need to adjust the pilot light adjustment screw to achieve a 25mm or 1 inch pilot flame length, it takes quite a bit of screw adjustment to take an effect.
Anything other than a correct pilot flame will burn out the thermocouple within a year or so.
Check the main burner flames, ideally they should settle to bluish flames with some orange tips not yellow, the tips of the flames should be close but not touch or lap the bottom fins of the heat exchanger, if they do you may need to adjust the governor adjustment screw for correct burner pressure.
If all that did not cure the problem only then start to suspect a faulty gas valve unit as they are very expensive.
Remember that for an occasional loss of pilot light can be a downdraught from the flue on a windy day or a vacuum cleaner exhaust blowing under and towards the fire.
Notes:
You must be either a qualified or competent person with sound knowledge when servicing gas back boilers.
You must check for gas soundness after completion with suitable gas leak detector and or appropriate gas liquid spray for leak detection, you must have a carbon monoxide detector in the room of the boiler.
You should inspect the flue and chimney and carry out a smoke bomb test correctly and fire spillage test.
Always refer to the service manual which is available online.

Jeff Ants
December 2016

Hi, I have a Baxi 552 boiler. The pilot started cutting out yesterday whilst running the central heating but appears to work fine when only heating the water. I noticed that it generally cuts out after 20mins heating and there's a loud click as this happens. I had the thermocouple changed last year (Oct 2012) when it was doing the same thing so am not sure whether its the same issue. Any one got any other ideas as to what it could be?
Thanks

Steve
January 2013

Hello I also have the baxi 552..My pilot light is lite. But will not kick up.So we have no heating.. Any ideas please

maggie
October 2012

Some people are so thick don't attempt this fix yourself as you are messing with a gas safety device a thermocouple this must be done by a gas safe reg engineer or you risk gas explosion or carbon monoxide poisoning please please don't listen to fools they risk there lives to save £45 for engineer to fit no wonder we have so many gas related deaths

Stuart
October 2011

Cj if your old Baxi is past it you can now fit the new Baxi Bermuda BBU HE. It is a straight replacement for the old Bermuda. You will need to fit a new flue and it is a 'A' rated system.

KGB.
August 2011

get your self a gas safe registerd engineer problem solved

j.preece
December 2010

i have just had a issue with the pilot light cutting out all the time. Looking on all these forums i was going to replace the thermocouple but someone suggested high pressure blast over the thermocouple which i tried first. It has now worked fine for 1 day and it would not last more than 20 minutes before. cross fingers it stays going. P.S i had it serviced as well but it did not cure the problem. Maybe a brush is not as good as a pressure blast. Good luck all

Andy R
October 2010

Hi, i Have just had a similar problem with my Gas Valve V4600C1029 for my 551 boiler same as the 552.
The grey button on the gas valve would click and turn off the gas when i put the cover back on after the boiler working perfectly with the cover off. After getting a new gas valve (thinking it was a faulty solenoid) and thermocouple thinking this would cure it, i was disheartened when it didn't. After much thought, searching the internet and contacting a Baxi technician, i realised the pilot light wasn't heating the thermocouple at the correct temperature (Omhs Setting - 5). All i did was adjust/increase the pilot light to a higher flame hitting the thermocouple and it cured it. what was happening was when i put the cover back on the boiler, the draft of air coming in to feed the burner below the cover was lifting the pilot flame away from the thermocouple and the thermocouple would then loose it heat and then the solenoid within the gas valve would the click the grey knob and turn off the gas.

Hope this helps somone in a similar position.

Paul
May 2010

my pilot light is on but as soon as you put the cover on the boiler it cuts out why is this?

Mandy
April 2010

Thanks for the info on the thermo couple just one question should the grey nob stay in when the pilot is lit ? i assume it should as when it comes out the gas goes off on mine at the momoent , cheers for any furthewr info guys n gals
regards Neil

Neil
March 2010

I recently had the same problem. I bought a new thermocouple but this did not cure the problem. I took the gas valve into work and a workmate said he had the same problem which was the solenoid. The wire had come adrift on one of the coils. We pulled it back, scratched the insulation off and trapped it between the metal and the plastic sleeve. It now works fine. The cover has to be removed to do this so be careful that the gaskets are properly seated. Don't attempt this unless you are competent to do so!

Gazzer
March 2010

Hi all, just for anyone reading these threads on the same problem i have had, Baxi Bermuda 552 back boiler pilot light won't stay alight!! the thermocouple was the problem, i got one from a local plumbing merchant for £8 and have to say it is a very easy DIY job to do,of course there is the small problem of one coupling to disconnect to be able to remove the wall mounted fire to enable you to gain access to the back boiler but as long as you are comfident in what you are doing its very easy,first turn your gas supply off at the mains,then hold in the pilot light valve and ignite it to burn off the gas still in the pipes,when the light goes out there's no more gas,remove the front grill and the radiants,disconnect the small coupling at the lower front R/H side which supplies the fire,remove the fire controll knob and 2 screws on holding wall brkts, and lift the fire off to gain access to the boiler,remove the large heat shield on the front of the boiler (3 screws),remove the heat shield from the Honeywell valve (2 screws on L/H side),now you have easy access to the thermocouple,you will need a 10mm spanner to remove the nipple from the valve end and 12mm to remove it from the pilot light end,remove the old one,fit the new one making sure not to cross any threads,job done,replace everything back where it came from,when i put the fire supply coupling back on and turned the gas back on i used a water and washing up liquid solution to check it wasnt leaking just to be on the safe side!! hoovered all the cobwebbs and dust from in there, relite the pilot and hey presto it stayed on and my heating is now working again,if i had called a heating engineer out i'm sure it would have cost the best part of £100 but it only cost me £8. so as long as your comfident in what your doing i say DIY. All the best

Steve
February 2010

hi i have an old back boiler and fire, i would like to fit new fire is it only the vp3 fire that will fit
christine

tina
February 2010

my pilot light went out today and we have spent 6hours trying to relight it when it lights up and leave the grey button it goes out please help

sharon
January 2010

The Baxi Bermuda 552 won't take a universal thermocouple - the thermocouple is an integral part of the thermostat and cannot be changed. It's available from here: http://www.e-gas-boiler-spare-parts.co.uk order number 042818.

Or do a Google search for Baxi part number: 230336

Wayne D.
July 2009

change the thermo couple
you can buy these at the plumbers merchant,
you need a universal one,
so that you can fit the new one in the existing
threaded hole .
its made of copper and sits next to the pilot light,
remove it by unscrewing the end that goes to the
thermostat housing and also the bit that,s near the pilot light,discard it and replace with anew one.
make sure that fitted the end of the coupling is in the flame always.
good luck!!!.

danny
October 2008

Can anyone tell me how many btus baxi 552 provides? Ours is positively ancient and I want to change heating system but need to know current provision. Many thanks

CJ
June 2008

change the thermocuple if that dont work its the soinoide on the gas valve

sam jones
October 2007

The back boiler can only be accessed by removing the fire front which involves breaking the gas supply. This should only be done by a competent CORGI engineer with the appropriate training and test equipment.

The thermocouple has probably failed.

Your boiler does need servicing every year and it sounds as if you have not bothered to have this done. Each year a few people die from CO poisoning from your model!

Tony Glazier
October 2007