RichardW wrote: 27 Nov 2017, 13:01
As myglaren, no idea what the tank is for; it's got lots of internal pipeways and things, and at least 3 outlets off the bottom. There is some fouling inside, as Steve notes!
Mandrake wrote:which I'm not allowed to change myself since it would disturb gas lines
Actually, nothing to stop you doing that - the gas regs only require any one doing gas work to be 'competent' - it's only when you get into charging for the work that you need to be certified. Changing the fan on ours involves disconnecting the gas supply to the burner.... Am I competent
Are you sure about that Richard ?
I'm a regular on a heating forum as well and a couple of the members are in the trade gas safe engineers and are pretty adamant that the regs do not allow someone who is not gas safe to carry out any work that requires breaking the seal of a gas part of the boiler, meaning disconnecting gas lines (gas leak risk if not correctly resealed) or opening the seal on the main fire box (CO leak risk) etc...
Like the rest of you, I'm pretty confident in my abilities to do the kind of work that experts say DIY'er shouldn't do, (it's never really stopped me before

)
however what I lack is any sort of gas leak detector. So although I'm 99% sure I could disconnect and reconnect a gas line and seal it properly, without having a leak detector I would not feel comfortable doing this as I couldn't be certain that I had got it right - compression fittings can be funny old things, even with water, let alone gas!
That one time you didn't quite get a good seal due to a poor olive or a scratched pipe could be a doozy - if water leaks out you can see it and tighten the joint a bit to fix it. A small amount of escaping gas into a closed boiler closet could go unnoticed - especially when you have as poor sense of smell as me!
If you guys want to re-seal gas lines without a leak detector that's your choice I suppose. If I had a leak detector I think I would probably do the gas side as well, even though technically I shouldn't.
So for lack of a gas leak detector I don't touch the gas lines of my boiler, however I am willing to work on pretty much any other part of it. The plumbing side, wiring etc, no problem, and I replaced the gas control electrovalve as it is just a slide on unit, and also replaced and rewired the main power cable to it some time ago which was getting a big shabby... (As well as retrofitted an external digital flow temp thermostat)