Wood Burning Boiler Stove - plumbing of...

[Norcon]

Your tuppence worth is welcome but that is all it is!

What ever.
As a seasoned pipefitter I know which option I would be using and it wouldn't invlove running pipes through the loft or under the dining room floor.
OOh and btw I can light my fire using a half sheet of newspaper.

(You're as predictable as ever puller)

 

[Norcon]

Its in my own home and been that way for about 8 years.
And if you can post any relevant information from Boyle's and Charles' Laws that might lend some credibility to your suggestion that it is dangerous then feel free.
And btw it wasn't advice.
Was just stating how it was done in my home.
If the original timeserved plumbers hadn't messed up the installation then I might have left it alone.

 

[tamz]

I'll use these figures for sake of counting

Volume of back boiler 25litres
T1 = 15 degC = 288K
T2 = 400 degC = 673K
P1 = 1atm (roughly = 1 bar)

Charles' Law

V1/T1=V2/T2
25/288=V2/673 V2=58.42 litres

Gay Lussacs Law

P1/T1=P2/T2
1/288=P2/673 P2=2.337atm

Proved using the combined gas law

P1V1/T1=P2V2/T2 (try the numbers)

Just incase you don't like the calcs read this

http://www.hse.gov.uk/services/localgovernment/boilers.htm

 

[Norcon]

Thanks for the concern guys but I've got away for eight years with no problem.

Look at what the hse document says..

4 What causes the problem?
The back boiler unit typically consists of a fire grate, which carries the combustible material e.g. coal, and a water chamber ‘surrounding’ it. This water ‘jacket’ is generally behind the fire but may also be at the sides and partially above the grate with the flue passing through it. Thus heat input to the water is gained from the hot flue gases as well as radiated from the ‘coals’. As the units are difficult to drain completely there is likely to be residual water in the redundant boiler which will turn to steam when heated. This exacerbates the pressurisation if the unit was left in a sealed condition.

Not the case when I sealed the pipe ends off my boiler as all the water was boiled off.
The house was like a sauna that day. LOL. I ran it for a few months until I eventually got fed up with the pong in the room so arrived home one evening and took a tin of expanding from the van and did the deed.
Sorted.
If it blows its just me that will bite the dust so don't concern yourselves too much although I expect you'll be worried about the neighbours.
Well the closest one is a mile off so he should be OK.

 

[ericmark]

Knowing my son and daughter-in-law are fitting solid fuel heating I was reading comments.

They tried a thermo-syphon system which failed and are now using a pump although there was some thermo-syphon it was not enough to stop boiling however it does not boil with enough vigour to a real problem just loads of steam.

As already said there is a temperature switch so pump only runs as temperature rises.

One point I have not seen referred to is material of header tank their first one was plastic and this has been changed for stainless steel because of problem in plastic tanks failing when filled with boiling water.

For them it is not a problem but in a house the immersion heater needs a special thermostat as most have non re-settable over temp device so if it fails it will open circuit and would need replacing. However with solid fuel a thermostat with re-set button is required as the over temp may be nothing to do with electric heating and one does not want to have to replace when there was nothing wrong with it. In my parents house as a lad it was common to have to re-set the thermostat when water had previously overheated.

I would agree thermo-syphon must be safest method and from tests it seems once the circulation has started it does continue even without the pump. But with max head of 6 foot it would not start fast enough.

Had wondered about safety plug! I know many systems are built with weak spot so should the pressure rise then it will fail in a safe place. Ideal would be into fire! I know my parents had a few boilers blow before going from copper to stainless and it was very effective at putting out the fire.

However their kitchen was quarry tiled floor with fall to back door. My sons kitchen has tiled floor but is below water level so any leak/burst would fill bilges and likely also would contain ash so not nice to pump.

So any further thoughts? P.S. I am an electrician so don't know plumbing law. However electric regulations don't exist for my sons home. Too big for RCD and not covered with BS7671. Guess same on plumbing.

 

[mdurkin]

Hi All,
After a fair bit of research, and a weekend spent tracing out my existing plumbing, I thought I'd post an update.
The gravity circuit is near impossible so I can't do it. Basically there's not enough space in the loft around the edges of the room for me to get in and run pipes. Yes I can get in but access is really tight, and at under 10 stones, I'm pretty small. Unless I resort to a midget plumber, or ripping half the house to pieces it's a no-go.
So...
In answer to ericmark - it is possible to run a pumped system, and it does need to be triggered at a certain temperature to make sure the boiler runs efficiently and condensation isn't caused. But there should also be some additional protection. Here's what I think I'm going to do:

Pumped circuit through stove, triggered by temperature sensor behind stove so pump only runs when efficient temperature is reached.
small gravity circuit behind stove with heat exchanger, and dump connected to mains with a 95degree valve (so emergency heat dump on small gravity loop).
I found the details on www.heatweb.com - I'm probably going to buy one of their cylinders. They show all sorts of options and this is what they suggest if the cylinder can't be gravity fed.
here's a direct link:
http://www.heatweb.com/xcelinstall.pdf
see page 18.
I thought this might be of interest as the document describes all manner of installations and would be of help with any setup not just ones involving their equipment.

I'm just wondering how easily I could hide the small gravity loop behind the stove - the neatest way of getting it all installed. If I boxed in behind the stove is plasterboard heat proof? (i.e. there's a lot of heat back there behind the boiler)...

still researching, and need to get some floors up...

 

[Biggles..]

What about pumping the stove controlled through time clock,high and low limit pipestats, then no need to worry to much about routing to ensure gravity flow.

Pipestats stop pump from circulating The hot water in the store back to a cold stove until the stove is up to the required temp.

Store still warms like a buffer. Too hot no boom as anti boil relief to drain operates.all standard fittings on a dps store with solid fuel input.

4 pages and we are back to these two statements made at page 1 without all the name calling.What would a DPS installer know

for those who havent seen a dps store,heres one.

28Kw gas boiler,50Kw stove runnign 5 bathrooms,150m3 underfloor and first floor radiators.

View media item 19282 View media item 19283
Lee

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[mdurkin]

lol. It was a good journey for me to go on though, and I'm such a visual person, I needed to see the drawings to understand it properly. I still need to understand a bit more about the anti-boil to drain - I haven't got much space behind the stove and I could do to hide the piping.

So my remaining problems (design related) are just weight I think. I was wondering if I could install a smaller unit in the exisitng airing cupboard upstairs, coupled to a second much bigger heat store downstairs (say in the garage). The reason I'm thinking this is that it would good to store a good chunk of heat every evening, so the house is warm when we get home the next evening, before lighting the stove. I don't like my chances of putting that monster in my airing cupboard though!!

this weekend I'm pulling up carpets and floors to find the rest of the existing plumbing and look for suitable routes for the new circuits...