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Nathan · Joined: 03 May 2008 Posts: 5 Location: CARDIFF

Hi there, I am new to this but thought i would give it a shot

I have a MAIN Combi 24 HE boiler, Since Friday Morning the boiler hasnt worked, no hot water no central heating. It was installed about 15 months ago, and no garantee / warranty anymore.

I have had a look at a few other posts on here, and thought a few things may help in a diagnosis.

The pressure gauge is just below 2, the pump seems to be buzzing so i assume its working, The boiler power light is on and the "flame failure light" lights up red every two seconds. Also burner light does not come on at all, pilot light is not on and There does not seem to be a spark, I have used the reset button but that doesnt work either.

I have had a read through the manuals provided with the bolierand says theres a blockage with flue, problem with flue terminal or internal problem. It then goes on to mention quote"PCB - M4 connector is approx 230v AC, terminals 36-38, if this is yes, it then says replace gas valve.

I suppose this could be the answer or the easiest one to do, However through your experience I was wondering if there were any other remedies i could perhaps use or do safely which would resolve the problem, before i pay for a guy who charges £50 for 30 minutes, £45 there after plus parts. As you can tell im trying to save money.

All advice would be greatley appreciated

thescruff · Moderator Joined: 03 May 2003 Posts: 4164 Location: Bath

The pump may be buzzing but is it spinning, if you have a small compass hold it over the big screw in the center of the pump, it should wizz round like a top.

Nathan · Joined: 03 May 2008 Posts: 5 Location: CARDIFF

Unfortunately I havent got a small compass, is there anything else i can do to check if the pump is working, also could this stop the boiler from lighting up, also could it be something electrical.

AlanE · Posted: Sat May 03, 2008 3:22 pm Post subject:

AlanE · Posted: Sat May 03, 2008 3:28 pm Post subject:

Nathan · Joined: 03 May 2008 Posts: 5 Location: CARDIFF

AlanE · Posted: Sun May 04, 2008 10:11 am Post subject:

Your quote refers to section 'F' of the chart. What led you to that section - a pin??

The chart takes you through a fairly logical sequence FOLLOW IT don't just jump about. You have no burner lit so you think no gas but as explained above unless the boilers initial tests ALL PASS, and these checks are carried out every time the boiler is called upon to supply heat, the boiler will STOP at that point.

I might use the chart as a last resort, but then I know my way around these boilers, it's my job, you don't. Follow the chart, do what it says to check components, and post back where the boiler is halting. That way you stand a real chance of fixing it without just swapping expensive parts until you just maybe happen upon the faulty component. Working in a haphazzard way you stand a good chance of still not getting it to work!

Nathan · Joined: 03 May 2008 Posts: 5 Location: CARDIFF

Think im gonna just get a guy out, havent got a clue about any of this, not sure how to clean it out, or to drian it, im not ignoring it just dont know where to start, thanks for help, but im out of my league here

AlanE · Posted: Sun May 04, 2008 1:06 pm Post subject:

Nathan I read what you posted and must say I admire you. It is a skill that more DIYers need to aquire. To know when to stop rather than go blindly on regardless.

It is ok having a go, even with fairly detailed instructions, but never if there is a chance of making things worse.

Would be interested if you could post here what they find. Everything always helps the knowledgebase for the future.

Nathan · Joined: 03 May 2008 Posts: 5 Location: CARDIFF

A guy from a respectable company came out, Had a look at the boiler, although cracked the condesate trap was still working, and not leaking yet. The main problem was the pump, when the screw was undone large amounts of black gunky water came out, and that was true for the entire system when drained.

It turns out by the opinion of the guy who came out, the installer said he did things which possibly could not be true such as installing an inhibitor and a sludge remover, if this was case a year done the line i wouldnt have this problem, also the electrics were a cowboy job, but still working but not compliant, quite worrying!!!.

I think although larger companies charge a little more ie British Gas, i think its worth the amount they charge at least you know the job was done properly and may not cause a problem later on.

The guy charged me £50, bled the system, got it working, Although i may have been able to it myself, and posted above i wouldnt know where to start and may cause more harm than good, a well paid £50. He showed me how to check it in future to elimate that problem if it doesnt work again.

AlanE · Posted: Tue May 06, 2008 9:17 pm Post subject:

Thanks for posting back. Glat all sorted.