Does anyone have experience of open fire back boiler plumbing?

[Neilmac]

Hi all, wonder if there's a tradesman on here who has experience of open fires with back boilers. Just moved into A 1980's semi in a rural area, which has a traditional open fire. It obviously has a back boiler as there is a damper. There's a box-in at the side of the chimney breast. Two 22mm copper pipes then appear in the airing cupboard. These pips are connected to the hot water cylinder indirect coil. Problem is this, as far as I can see, it appears to be a sealed system. No expansion pipe into the loft tank, no top-up feed nothing. Just a back boiler, two pipes and a coil. Does anyone have any ideas? Oil filed? Any help or advice greatly appreciated.

Bit more background, that might be helpful. The house has no 'wet' heating system. Just electric radiators. Only plumbing in the house is a bog standard gravity fed system.

 

[deg]

You sure the cylinder has a coil? Sounds like a direct cylinder.

 

[ShaunCorbs]

will be the very old type where it uses your cylinder water (your hot/cold water in your cylinder) to fill and will vent via the hot outlet like a normal cylinder (no coil in cylinder)

and will work on gravity circulation

if you can best bet would be to get the lot ripped out and install a new system combi boiler or heat only boiler and cylinder

best speak with a gas safe engy about your options

where are you located if you dont mind

 

[snowhead]

As above, the cylinder will NOT have a coil.
The water in the boiler behind the fire is the same water that comes out the Hot tap.

 

[snowhead]

double post

 

[Neilmac]

Hi, thanks for your reply. No, I'm not 100% it has a coil, that sounds like the answer I hadn't thought of.

 

[Neilmac]

Hi, and many thanks for your reply. Would love to fit a combi boiler but not on the gas grid. Just fitted electric heating and really impressed with it. But still intending to use open fire and wanted to know that system was safe before lighting a fire. It looked like a sealed system to me but common sense told me that wouldn't be safe at all. hadn't thought of it being a direct cylinder. Dhhhoooo.

 

[snowhead]

Removing a back boiler. Get it wrong you get very wet! | The Stove Fitter's Manual

It's either the original type , 1st pic, with the flueway built from brick but obviously not blown apart like that one!!

Or it's a complete unit like the second pic.

 

[kris]

Yeh like previously mentioned it's an old style direct water heating from the coal fire, now although this is cost effective it maybe an option to upgrade to a more efficient system, obviously cost comes into it as well as is there gas in your area etc, even multi fuel stove with back boiler , hw tank and rads ( talk to hetas approved installer for this ) or even look at options of keeping your fire and upgrading , electric usage on electrical heaters can be high so best to calculate long term adv and dis adv, or if cost isn't an option then multifuel stove with back boiler interlinked with gas or oil boiler , I've done a couple with brilliant end results ,

 

[Neilmac]

Really appreciate the replies, all now makes sense. One more quick question guys, if this is a direct system and her indoors lights the fire on a cold day and keeps it burning all day, forgetting to close the boiler damper. What's to stop the cylinder overheating and ending up full of scalding hot water?

 

[snowhead]

What's to stop the cylinder overheating and ending up full of scalding hot water?

Nothing.

And the header tank, which should be metallic will heat up as well.

 

[Neilmac]

Its a plastic tank, and doing a bit of research before posting, read that someone was killed when a plastic tank softened and showered them with boiling water. Scary thought. I would have thought that modern regs would have introduced a safety feature into a direct system like this to make sure excess heat was dealt with by shutting circulation down with a thermostatic valve etc.

 

[ShaunCorbs]

Its a plastic tank, and doing a bit of research before posting, read that someone was killed when a plastic tank softened and showered them with boiling water. Scary thought. I would have thought that modern regs would have introduced a safety feature into a direct system like this to make sure excess heat was dealt with by shutting circulation down with a thermostatic valve etc.

dont use the fire what ever you do as you've said its likely the plastic tank could go

and tbh theres not many left these days

 

[snowhead]

I would have thought that modern regs would have introduced a safety feature into a direct system like this to make sure excess heat was dealt with by shutting circulation down with a thermostatic valve etc.

The best you can do on an old system is a heat soak radiator, usually in the Bathroom.
You can't cut off the flow, you'll end up with picture 1.

Regs aren't usually retrospective.
A modern solid fuel system does have safety features.

 

[Neilmac]

No, won't be lighting a fire and risking that. Not being on gas grid, and house having electrical heating (new, highly effective and far more economical than people imagine), I think best solution would be to de-commission back boiler, open fireplace up and have a modern multi-fuel stove fitted. But that's a topic for solid fuel forum. Many thanks for your replies, very much appreciated and very useful.

 

[REDSAW]

take advantage of the situation and fit a log burner with heat ex

 

[joni os]

Good decision not to use or waste money attempting to upgrade existing. If tank is bare copper without foam insulation, then whether direct or primatic it will be old and most probably full of sludge. Consider wood burner with back boiler to be self sufficient in case of power cuts etc, One tonne of dry wood should give 3000Kw of heat. Wood at £150/tonne equates to 5 pence/Kw. Installer should be Hetas registered for wet system. Don't invest in too big a stove or room will be overheated. A stove burning clean at rated capacity better than larger smouldering stove. As property is semi, talk to neighbours and learn from any mistakes they may have made.

 

[REDSAW]

how much a tonne?@~@