De-commissioning back-boilers?

[zoew]

Putting a new back boiler in safely. Plumber says boiler for water not safe to put pump on for radiators ? Why not if bubbling means time to circulate? And nice and hot? Zoe

[Tim Watts]

Any chance of that in English?

[Dave Liquorice]

Soild fuel heat source? There has to be a gravity loop to get rid of the heat in the boiler or it will boil and when they do it's not a gentle little bubling noise but sodding loud bangs an wooshing noises.

There can be a pump to circulate water around the rads but it must not be in the gravity loop to the HW cylinder and/or heat dump radiator.

Is the back boiler the only source of heat for the system or is there also a gas/oil boiler as well? Getting them to play nicely together is beyond most "plumbers". It's not difficult but you need to know what you are doing.

[johnrowlands43]

I would advise looking at what the HSE guide lines are ! they recommend removal of back boiler rather than venting although this is an option. having worked in the industry some 16 yrs, my safety concerns are fumes and smoke usually find their way up the redundant channels and pipes ! Stick to HSE guidlines would be my advise.

[Andrew]

Well *I* would read the bloody DATE of the posting and its replies.

You obviously didn't and are 8 years too late. Where did you trawl up this old posting from ?.

And making reference to the HSE on DIY newsgroup isn't going to make you very popular, especially if you actually work for them.

[Graeme]

Shall we make that 9, this year? :-)

[Brian Gaff]

Blimey this thread has a checked history over many years, but we when we moved in here did not even realise there was a back boiler in the fireplace, it was only later on when we needed a new hot water cylinder that the plumber found it which had been disconnected and stop ends put on the pipe it was still full of water and had not leaked after over 30 years. He of course stuck a hose on a tap at the bottom and drained it. It was amazing that we had not had a flood in those 30 years or so. Maybe they made things a little better back in the 1930s! Brian

[Marland]

If that is as exactly how you described it then whoever undertook the original disconnection did exactly what should not be done. A drained back boiler is just a lump of Iron or occasionally copper which will get very hot which may or may not matter depending on what surrounds it, one full of water and capped becomes a sealed pressure vessel and if it or bits of capped pipe connected to it rupture under pressure then the results can be nasty, low end is a split and you get a puddle for a while, high end is a sudden explosive failure which could well be strong enough to cause a lot of damage especially if it blows the contents of the burning grate into the room over everything including occupants.

Ideally a disconnected back boiler and piping should be filled with sand though if it is left uncapped pressure should not build up.

GH

[S Viemeister]

Mine was left uncapped, drained, had a number of holes drilled into it, and was filled with sand. And the new combi has saved a fortune in heating costs.