My diaphramn valve is faulty, the actual diaphramn has been taken out as it has melted, so the entire valve is now deemed faulty. Any tips? Apparently £150 for the part and £150 for fitting, your just down the road from me...it's a Ravenheat LS80 boiler.
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Check out keeptheheaton.com or it might be co.uk
They carry stuff Vallient themselves don't seem to, sell it at a reasonable price and get it delivered really quickly; the next day in my experience. I was quite happy to put the free sticker they included on the boiler, with their number on it.
Find the replacement diagphragm, then take the valve apart and swap em over.
If you have the technical manual for the boiler, or can get a copy from Ravenheat or on line, there'll probably be a troubleshooting guide in there that tells you how to do it. The builders, plumbers and electricians I've seen usually just open the guide and follow that. The one for even our really old combi walked me through things in a "does this happen? yes / no, then do this ----->" tree fashion.
Taking the valve apart isn't hard, but you may have to disconnect some other junk in the way before getting to it. Mine was one of the first combi's and it was buried behind the pump and a fair bit of pipework. Just unbolt it all, get to the sucker, then put it all back.
Before starting, identify the gas line and don't touch it. You can either do that from the outside and follow it in (e.g. the pipe that isn't hot or cold) or from the inside, the pipe that goes into the burner. It'll be in the technical guide too. I'd recommend you do all three. You don't want to unbolt that by mistake, obviously. Particularly if you smoke. Once you've found it, colour the pipework connected to it in with a marker pen if you want to be sure you don't mix them up whilst unbolting things. If the gas line is opened, you have the immediate fire risk, but you also need to do a pressure test on the mains after putting one back together, to check it's not leaking at a very slow rate.
I just had a look on EZparts.co.uk (ezyparts?) and they seem to have the replacement for £14 (first price I found).
If you take a photo of the boiler with the cover off, I may be able to point to what is what and what needs to happen.
The diaphragm goes on these things, combi's, a lot of the time. Particularly the older ones. They just wear out from the heat and constant bending. Some newer ideas use different types of sensors.
If someone has identified that the diaphragm has melted and is then suggesting you pay £150 for a new one, you're probably dealing with;
1.) Someone who doesn't realize they can buy a new diaphragm and it'll work fine again
2.) Someone who does realize that, but knows they can get away with charging you £150 and pocketing the other £140, because if you tell another plumber "the diaphragm valve broke", they won't know if you mean the whole valve it's self or the bit of rubber.
There is a very strong possibility of one of those being correct.
The price for the actual work, that depends on how well buried it is and how tricky it'll be. But £150 is about what my brother earns per day (maybe more), working for big law firm in the middle of London on IP rights for Boeing, Durex, Mars, Nike, Adidas (footy shirts) and others like that. So that plumber better get it done and fixed so it'll work for a few years at that price - especially since he probably isn't paying any tax on it. And since I managed to do it in a day having never touched a boiler before.
If they're doing any gas work, try asking them about Corgi and see how they react.
Our plumber assured us his training was up to date. I'm now almost sure he didn't have a card.
The cost of a new valve is due to all the machining involved (the brass is about £5-10 in scrap I think). But it's not that bit that breaks, it's the bit of cheapo rubber inside.
So, it's quite possible you could have this fixed in a few hours for literally 20x less money.
Plumbers and roofers love scrap. Quite often when they fit a new boiler, they can rebuild or straight up reuse the functioning parts from the old boiler. E.g. drop in a diaphragm from another they just scrapped and charge you the full price. The lead from a roof and water mains swap is worth about £150-200 in scrap. And all the copper / stainless / brass in a boiler is worth a fair bit more than broken bricks and bits of timber.
I saw a funny little sh1t on Rogue Traders who'd do things like, tell people they needed a new fan (when the pressure switch had just been disconnected), take it out, go outside, then bring the same one back in, refit it and charge £400. They knew it was the same one, because they watched him do it on tape and had written on it with a UV marker pen.
Setting up the gears on a racer so they don't chatter is harder than doing the diaphragm on a boiler. I tried doing the grip shifts on my brother's fancy racer and it was a god damn joke they were that tiny, complex and tricky to get together. The diaphragm isn't.