In article ,
Capitol writes:
wrote:
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

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:-


https://www.keeptheheaton.com/produc...Yq0wodes 4JPg

Gas boiler of that age I used to service had a completely different
design of gas valve. It used (abused?) a pressure reducing valve to
operate as a gas valve for the main burners. It exposed what would
normally be the air pressure side to gas pressure via a tiny orifice,
which shut the thing off. To turn it on, it had a tiny gas valve which
let the gas pressure leak away from the normal air side, which opened
the pressure reducing valve (and it burned the leaked-away gas in an
extra single burner).

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.

If it's that bad, I would say it's had it. However, I never saw a
burner that needed anything other than cleaning.

Like I said elsewhere, no evidence was posted that there was anything
wrong with the valve or burner (beyond normal servicing). I strongly
suspect the problem is blocked flue channels through the heat exchanger,
having serviced similar boilers myself in the dim and distant past.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]