open fire backboiler connections

[repton]

Hello,

I'm currently trying to figure out the plumbing in our house ready for some fairly major work and having removed a panel covering the pipework to the back boiler on one of the open fires I've found something I wasn't expecting. There seem to be two pairs of pipes going into the masonry. One is a pair of 28mm pipes that go up to the heating coil in the hot water cylinder (and to the header tank in the loft), and the second pair are 22mm pipes that (via the pump) feed the 5 radiators in a loop.

Photo here.

Is it likely that the back boiler has more than one loop, or is it more likely that these two pairs are actually linked somewhere within the brickwork of the fireplace and connected to a single loop in the back boiler? I'm assuming it's the latter as if they're completely separate than I can't see anywhere in the system that the water can actually get into the heating loop.

I'm installing a Dunsley Neutraliser upstairs as I want to link this backboiler with one on another fire, so I'm hoping the latter is the case and then I can presumably leave the 28mm pipes as they are, cap one of the 22mm ones and fit a drain valve to the other 22mm one.

Anyone any ideas?

Ta,
Paul

 

[bathroomboy]

Don't take this the wrong way but you really have to now what your'e capping off and piping up, solid fuel fires are uncontrolable and you could end up with a serious explosion.

By the way the 28m/m are most likley gravity feed for the cylinder, the 22m/m are probably pumped for the rads.

 

[migoplumber]

take extreme notice of bathroom boy! you are entering an area that really is for proffesionals. mistakes on that type of installation can be devastating and deadly.

why not get an engineer in, explain you would like to help with the work, and see what he suggests?

good luck
shaun

 

[bathroomboy]

I agree Migo this needs careful planning by someone with solid fuel heating experience, can be volatile if not right.

 

[repton]

By the way the 28m/m are most likley gravity feed for the cylinder, the 22m/m are probably pumped for the rads.

That is definitely the case as that's where the various pipes lead.

The only way of getting water into the system is up in the airing cupboard on the 28mm loop near the cylinder connections (where there's a feed from the small cistern in the loft on one pipe and a beather pipe that goes up to just above the cistern on the other), and the only drain cock on the system is at the bottom of the 22mm radiator loop, so the fact that the whole system does drain when i open that single drain cock implies that the two are interlinked somewhere within the fireplace.

Thanks for the warning about sealing back boiler connections, that's why I was asking on here really as I've read plenty of scare stories about exploding back boilers where connections have been sealed up. I'll make sure I'm not creating any completely sealed sections by checking what goes where once the existing pipework is disconnected, but for now I'm just trying to work out as best I can what I have before I start cutting pipes (or knocking chunks out of the fireplace...)

Paul

 

[migoplumber]

its not just about sealing pipes up paul, there are many and various safety devices installed, if you miss something and cut one out it will be a big problem.

also when you have located the pipes and marked up which pipe does what, no engineer in his right mind would just believe you and connect up.

all the safety devices will have to be tested, the system will need commisioning, something that has to be done by a pro.

just expose your pipes and call the engineer in, even if you just pay him for a couple of hours advice, he would of actually seen your job, and should be able to give you some more in depth advice.

what sort of experience do you have in plumbing/heating ?

shaun

 

[repton]

its not just about sealing pipes up paul, there are many and various safety devices installed, if you miss something and cut one out it will be a big problem.

What kind of safety devices? If there are any then they're very well hidden as I've exposed almost every pipe in the system and found nothing so far.

what sort of experience do you have in plumbing/heating ?

None before I moved in here but so far in this house I've completely replaced everything in the airing cupboard and loft, including the HW cylinder, both cisterns and all the interconnecting pipework. The current job is the neutraliser and then after that I'm installing solar water heating (the new HW cylinder I put in already has the second coil for that). My soldering may not be the neatest in the world but so far nothing has leaked. I do appreciate your concern but I'm not a complete numpty and fully intend to do all this myself. I've also rewired large chunks of the house and put an underground feed out to an old barn (having not done any wiring ever before either) and the sparky who came to test it all for the Part P certificate didn't have to make a single change to what I had done, much to his surprise.

Now does anyone have anything to say other than "get a professional in"? 😉

Regards,
Paul

 

[Bernie2]

I would follow Migo and Bathroom boys advice if I where you.

Err!

Being of an old age, I am familiar with the system you have got or if not exactly the same near enough the same.

Its usually a back boiler with four tapping's, two at the top for flows and two at the bottom for returns.
The 28mm are the Primary flow and return and the 22mm flow and return to the heating loop.
The 28mm Primary flow usually has a vent off by the cylinder to over the header tank/cistern, and the 28mm return has a cold feed from the same cistern.

You may even find a safety valve on the boiler pipework close to the boiler.

The central heating loop is fed with water through the boiler.

The air being released as it fills through the rads.

It looks to me though, and I admit I can't be sure, that the pipes are corroded, they don't look to be properly sleeved either if at all. The gas pipe or what looks like a gas pipe isn't even sealed sleeved.

If despite the contrary advice you still have a go, just make sure you don't touch the Primary pipework. The vent and cold feed routes from the header to the boiler are the main safety pipework as well as the primaries.

Incidentally the heating usually is just a loop. But you can have all kinds of variations.

And I would make sure it was well flushed before I used it if I where you.

But once again please whatever you do make sure you have free flowing open vent from the boiler to the header cistern and a clear unobstructed cold feed path the same.

And if you do a design, don't forget a solid fuel boiler will hold its heat for perhaps an hour or more, after you have shut the damper and even then still need a to dissipate surplus heat.

 

[repton]

The gas pipe or what looks like a gas pipe isn't even sealed and sleeved.

None of them are gas pipes, the nearest village to us with a gas supply is about 5 miles away!

On the photo the right hand two pipes are the 28mm ones going up to the airing cupboard and the left hand two (and the three heading down) are the 22mm heating loop. On the heating loop the middle pipe going off the bottom of the photo is the feed from the pump (which is under the floorboards next to the fireplace) into the back boiler, then the feed out of the boiler splits into a 22mm pipe heading to the 4 radiators upstairs and a 15mm one to the single radiator downstairs. The 22mm pipe that goes straight from top to bottom of the photo is the return from the upstairs radiators back to the pump.

The system you describe sounds like it is probably what I have got.

If this is the case I need to work out what I need to do to safely stop using the 22mm loop, other than open up the fireplace and cap them off at the actual boiler as that kind of destructive work isn't really an option at the moment. The radiators will be fed from connections on the neutraliser once I'm done, with the pump relocated next to it in the airing cupboard.

Simply capping them off wouldn't create a problem with a sealed box as the larger 28mm connections will still be able to breathe up through the pipework in the airing cupboard into the header tank, however this would leave me with no way of draining the system so I would at the very least need to run a pipe from one of them down to a drain cock under the floor where the existing pump is.

Thanks,
Paul

 

[Jason.S]

Paul,

The lads here are just merely expressing their concerns about your knowledge of this type of system, and trying to make sure you are aware of the potential dangers involved.

Dont forget they are also trying to help.

Good luck mate. 🙂

 

[bobpape]

The intricacies of the system set aside ask yourself how long will the existing
installation work for.

If you cant guarantee at least 10 more years of life, then on the grounds of economics and potential inconvenience it would be wise to seriously consider
complete renewal,

And please believe me when I say 10 years comes around pretty quick.

 

[repton]

If you cant guarantee at least 10 more years of life, then on the grounds of economics and potential inconvenience it would be wise to seriously consider
complete renewal,

That is my aim. Time and money permitting, by the time 10 years is up the open fire with back boiler I'm asking about here will probably be replaced by a Clearview stove (with back boiler) and the other open fire on the otherside of the wall will be replaced by a small Rayburn (with back boiler). The radiators and associated pipework will all also be replaced by then as most of the radiator pipework is fixed to the skirting boards at the moment and I want them under the floor ideally.

Paul

 

[bathroomboy]

Paul, like I said yesterday, I'm not saying don't do the work but what I am saying is that it needs a lot of thinking about, personelly it's not a job I would take on for a customer, I would leave this to an heating expert who has experiance with solid fuel installations, an explosion would be similer to an unvented cylinder which makes a gas explosion look like a damp squib, hot water and steam when it flashes off has a massive impact.
Don't forget it's not just the piping up, it's the design of the system which will be covered some by building regs,the heat is uncontrolable once lit, and therefore it has to be designed to get rid of heat in some way.
You really need to get the whole of the house system designed by an expert, not just for safety, efficiency as well, skip on these things now and you may have years of problems to say the least. Hope this helps. Rob

 

[Bernie2]

Hi! Paul,

Bearing in mind what has been said about safety.

I can make a bit more sense of the photo now.

Yes it looks okay to do what you propose, if your set on doing it, and would do it anyway regardless.

I would prefer to try and help you as much as I can, than let you go ahead without any sort of help.

The 22 mm pair are only really a flow and return loop.

As an added precaution, you could always cut the 22mm flow pipe, back into the wall and fit a safety valve on it, even if its already got one on it inside the fireplace itself. That way you would have the 28mm vent as a safety feature and a safety valve.

Don't forget solid fuel fires are uncontrollable really and can easily heat hot water way beyond a safe temperature. So there is a high risk of scalding from the hot water.

The HSE put out a good information leaflet on it and the Baxi Burnall leaflet gives you some ideas. But I have to admit the info is sparse.

 

[repton]

You really need to get the whole of the house system designed by an expert.

The system design I'm using is the one that Dunsleyheat have supplied to me to go with the neutraliser I am installing at the centre of the system, so it should be safe and hopefully pretty efficient.

For anyone who doesn't know what a neutraliser is, have a look at this: [DLMURL="http://www.dunsleyheat.co.uk/linkupsys.htm"]dunsleyheat uk manufacturers of multifuel stoves, range cookers, boilers...[/DLMURL]

Don't forget solid fuel fires are uncontrollable really and can easily heat hot water way beyond a safe temperature. So there is a high risk of scalding from the hot water.

The existing system that was in the house when we moved in had all those problems including being able to hear water boiling away in the pipes at times when the fire had been lit all day in winter!

The new design should sort this out. The output from the HW cylinder has a TMV on it to protect us from scalding, and the neutraliser will have a thermostat on it that automatically turns on the central heating pump to dissipate some of the heat through the radiators if the temperature of the water in it gets too high.

Thanks again for your comments,
Paul

 

[Bernie2]

Seems okay to me. You must remember though on the forum we have no idea who we are talking too nor they who they are.

So being on the safe side we have to be very cautious and add as many worst case scenarios as possible and as many safety warnings as we can think of.

Hope we never knocked your confidence at all, it was intended purely as a safety interest.

Don't forget the same would happen to me if I asked a question.

Anyway Paul the best of fortune, you seem to have it all covered. 🙂 🙂

 

[daza]

I would follow Migo and Bathroom boys advice if I where you.

Err!

Being of an old age, I am familiar with the system you have got or if not exactly the same near enough the same.

Its usually a back boiler with four tapping's, two at the top for flows and two at the bottom for returns.
The 28mm are the Primary flow and return and the 22mm flow and return to the heating loop.
The 28mm Primary flow usually has a vent off by the cylinder to over the header tank/cistern, and the 28mm return has a cold feed from the same cistern.

You may even find a safety valve on the boiler pipework close to the boiler.

The central heating loop is fed with water through the boiler.

The air being released as it fills through the rads.

It looks to me though, and I admit I can't be sure, that the pipes are corroded, they don't look to be properly sleeved either if at all. The gas pipe or what looks like a gas pipe isn't even sealed sleeved.

If despite the contrary advice you still have a go, just make sure you don't touch the Primary pipework. The vent and cold feed routes from the header to the boiler are the main safety pipework as well as the primaries.

Incidentally the heating usually is just a loop. But you can have all kinds of variations.

And I would make sure it was well flushed before I used it if I where you.

But once again please whatever you do make sure you have free flowing open vent from the boiler to the header cistern and a clear unobstructed cold feed path the same.
And if you do a design, don't forget a solid fuel boiler will hold its heat for perhaps an hour or more, after you have shut the damper and even then still need a to dissipate surplus heat.

hi i have what iv been told a 4 tapping back boiler but i have 2 28mm pipes ment to come out the side of the fore and 2 22mm pipes comming out the othere side of the fire but the 2 28mm pipes seem to of at 1 point come out of the side of the fire but have been joined togethere so now there are only 2 22mm pipes coming out of the right side of the fire that go to the rads via a pump can u help with some advise thanks

 

[desrob]

What kind of safety devices? If there are any then they're very well hidden as I've exposed almost every pipe in the system and found nothing so far.



None before I moved in here but so far in this house I've completely replaced everything in the airing cupboard and loft, including the HW cylinder, both cisterns and all the interconnecting pipework. The current job is the neutraliser and then after that I'm installing solar water heating (the new HW cylinder I put in already has the second coil for that). My soldering may not be the neatest in the world but so far nothing has leaked. I do appreciate your concern but I'm not a complete numpty and fully intend to do all this myself. I've also rewired large chunks of the house and put an underground feed out to an old barn (having not done any wiring ever before either) and the sparky who came to test it all for the Part P certificate didn't have to make a single change to what I had done, much to his surprise.

Now does anyone have anything to say other than "get a professional in"? 😉

Regards,
Paul

my advice is to offer you no advice at all and hope others follow suit, your terminology alone suggests your not competant.GET SOMEONE IN.