Boiler (combi) playing up again :(

martyp

Hi all,
I'm hoping I can get advice from a boiler expert on here again as I'm terrified of big bills...
My Glo-worm Hot Water Express 80 (about 20 years old?) has moments where the pressure has gone down or pilot light goes out and seems to really play up in the winter.
Now the pilot light seems to be ok and the pressure is ok but it doesn't make the 'click...rumble' noise when you turn the hot water tap.
Is there something that could be easily/cheaply replaced to get the click rumble noise back again and get hot water again.
I've found that giving it a hard thump seems to get it working again but I doubt that's a good thing and certainly not a long term fix.
It's just started happening again after a summer without problems and the only two different things I can think of are the external water being colder or starting to use the gas fire in the living room?
The central heating hasn't been used at all yet...
If someone can say 'that's the XXX valve' and I could get it off ebay for a tenner and fit it in seconds that would be perfect but I do fear it could be something complicated...
Can anyone help at all?
Many thanks in advance...

paulsad

I don't think there is anything you can do simply these days (or before really) to a boiler - sorry to say - my son is an engineer and we've just been to sort out a friends boiler - he uses a computer to diagnose the boilers now and really knows his stuff - you will have to get a qualified person to fix it I'm afraid - Gas and Electric are too dangerous to mess with.

ben2909

I had the same problem on a different make of combi boiler.

The problem will either be the mirco switch,or the valve.Mine was the valve and i just brought a new diaphragm.Your best bet is to dig the instructions out as they usually have some sort of fault guide that you can follow.

martyp

That's great, cheers. I did manage to find and download the repair manual so will have another look at that. I thought I'd check on here to see if anyone else had experienced the same issue, hoping it might be something well known.
I just checked ebay for parts and there are just circuit boards for over £100...
Will look into those two parts and check prices. I think my neighbour installs industrial boilers so may have the computer equipment...

gas4you

At 20 years old it could be said that the boiler has done very well, owes you nothing and is ready to be changed, rather than spend good money on it.

Domthemon

Tend to agree that a new boiler is the ideal route after 20 years. New boilers are so efficient too. If however this isn't an option I suggest you carry out some tests. Start the heating up then turn the hot tap. Does it fire up for heating first and then does it stay on and warm the water? Turn heating off. Leave tap on. Does it still work or has it switched off? Try now turning hot water on and off a few times. Does it work ok? Ditto heating.

It sounds like divertor valve but as correctly stated above it can also be the micro switch the divertor valve triggers. As these work together it is difficult to assess which is at fault without a meter and testing and watching the innards as the boiler is operated. You would be looking at over £100 supply only for a divertor valve probably £20-30 max for the microswitch.

martyp

gas4you wrote: »

At 20 years old it could be said that the boiler has done very well, owes you nothing and is ready to be changed, rather than spend good money on it.

I would love a new boiler but really couldn't afford one. I have my MOT in October, then car insurance in November followed by Christmas so really bad financially the next couple of months. My car is also around 20 years old and I just keep doing little repairs on it as I can't afford a new car either...
Really just want to keep the existing boiler going for as long as possible at the moment (in the dream one day my income will increase!)

martyp

DomtheMon wrote: »

I suggest you carry out some tests. Start the heating up then turn the hot tap. Does it fire up for heating first and then does it stay on and warm the water? Turn heating off. Leave tap on. Does it still work or has it switched off? Try now turning hot water on and off a few times. Does it work ok? Ditto heating.

Hi DomtheMon, many thanks for your help and advice.
I've just turned the hot tap on in the kitchen fully and no hot water and no click/rumble noise. I then did the tests as you suggested and when I turned the central heating on it instantly kicked in and the water started coming out hot. I left the tap on fully as I switched the heating off and the boiler went off and so did the hot water. I turned the hot tap on fully several times and it didn't kick in at all.
I turned the central heating on several times and each time the boiler fired up.

Hope this helps with the fault finding?
Do you know where I could get the parts from at all?
Many thanks in advance

Domthemon

Sounds like the divertor valve but best to take front panel off and locate the bit that moves and clicks when you turn the heating on. Then see if you can see the other bit on the valve that moves (it is usually like a pin that goes up and down) or should do, as the water is turned on. If the pin slides in and out against the microswitch when the hot tap is opened then it is likely the microswitch. If not then probably the divertor valve. I would guess a plumbing and heating merchants, but you need to drain the boiler off and have a reasonable amount of plumbing skills.