The gas valve and / or burner on my faithful old Sunrod G50 boiler have finally failed after about 50 years use.
Unlikely, I know, but I don't suppose anyone has these parts available, or any idea where I could get them?
I would really like to keep this extremely reliable boiler going if at all possible.
I'd appreciate any advice.
Many thanks,
John
Have you got the part number and make of the gas valve? (probably got more luck with that than the burner I would expect)
Thanks for replying. How would I find these?
John
Label stuck on the side of the valve? Failing this a photo would be useful.
Tim
Eg.
Tim
Please forgive yet another follow up, but, it occurs to me that given that you don't seem to know which part has failed it would be much more helpful if you could tell us what you *do* know.
Presumably it's an open vented, cast iron heat exchanger device with a traditional pilot light? There aren't a lot of failure modes to consider and it should be possible to narrow things down a bit better than "burner or gas valve".
Burners may rot or get blocked jets but don't generally "fail" so if it's not lighting you need to look "upstream".
Is the pilot light staying lit? If it is, does the gas valve click when there is a call for heat?
If it clicks can you hear a his of gas? If it doesn't click, it could be a valve problem or an electrical supply problem.
Does it have an overheat stat? If this has tripped it'll stop the gas valve opening.
Is your pump working okay? Failing pump could cause overheating etc....
Tim
Almost all these boilers used the same gas valves, but with different part numbers to confuse the public. Most were made by Honeywell and spares are readily available. Do a search and send out a few enquiries. About £200 is the going price I believe, but I managed to pick up a spare for £25 last year in the US, who use the same 24V gas valves. The detailed data for the gas valves is difficult to find, but I found a data sheet on a ck website after a lot of searching. Found this:-
The burner is more difficult. Is it the burner with holes in, or the jets? The jets are readily available. The burner should be repairable I'd have thought with a bit of welding.
Tim:
I'll take a look tonight to see if there's a label or take a photo. Replies below:
Presumably it's an open vented, cast iron heat exchanger device with a traditional pilot light? There aren't a lot of failure modes to consider and it should be possible to narrow things down a bit better than "burner or gas valve".
Yes. My CORGI plumber told me it was one of these, and to look on the internet to see if parts are available.
Burners may rot or get blocked jets but don't generally "fail" so if it's not lighting you need to look "upstream".
It will light, but blue flames immediately appear around the front of the boiler casing.
Is the pilot light staying lit? If it is, does the gas valve click when there is a call for heat?
Yes. Can't remember if it clicks, and it is disconnected now pending repair/replacement
If it clicks can you hear a his of gas? If it doesn't click, it could be a valve problem or an electrical supply problem.
Gas supply does not seem to be a problem.
Does it have an overheat stat? If this has tripped it'll stop the gas valve opening.
Not relevant, I think, as this happens as soon as lit.
Is your pump working okay? Failing pump could cause overheating etc....
Yes, no problem with pump.
Many thanks,
John
finally failed after about 50 years use.
or any idea where I could get them?
all possible.
I think it has holes rather than jets, but will check tonight.
Many thanks,
John
That sounds, um, a bit f*cked. ;-)
You really need to take a look at the burner to see what's what and if it's repairable. As John says, a replacement burner is probably unobtainable.
Tim
Sounds like the flue is blocked? Or there is a gas leak internally?
That doesn't sound right at all. Can you provide a photo?
I have known old burners needing a very good clean where the holes become partially blocked. Again remove and lets see some photos.
There's no gas leak. There was a fall of soot, but I thought the plumber cleared this when we had the problem. I'll contact him and verify again and report back next week. I do hope this is the problem!
Thanks,
John
Thanks - I think I'll have to get the plumber back and have a close look at this. Thanks for your suggestion.
John
Does it discharge into a chimney? Is there a cap to stop Jackdaws building nests?
Tim
This is a DIY group! Is there any reason why you can't remove the burner yourself? One of that vintage should come out quit easily though I can't find a manual for this boiler.
Reliable but crap efficiency & poor safety. If nothing else, check your fresh air supply is always sufficient & fit a CO alarm.
NT
Efficiency should be in the 78% region.
How do you get that figure?
NT
I would say a little over optimistic given its age. Its alos too old for any published rating.
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