Confusing back boiler removal - hidden equipment or broken water tank?

[zhuffzilla4]

I live in a 1940s semi, the only source of heating I have in the house is a hot water cylinder with an immersion heating the water, no pumps for the hot, just gravity feed (no gas, boiler or central heating just hot water for the taps)

I am attempting to remove an old condemned stove with a back boiler but when I drained the pipes going into the back of the stove the water wouldn't stop draining, and when I checked the hot water cylinder I could see it was refilling.

Coming off the hot water cylinder is the normal cold in, hot out, overflow.
as well as a couple of 28mm feed and return pipes going through what I assume was just a normal calorifier which goes directly to the back boiler (there is a also radiator teed off the 28mm pipes in the upstairs bedroom, no idea if it has ever worked as I have never lit a fire in the house)

My assumption is that I could just cap off the 28mm pipe going through the hot water cylinder, then the water would drain from the back boiler and job done, not entirely confident with damage I could do I called a plumber to do it for me which is when things started to get interesting.

The plumber was adamant that there is a expansion/filler tank somewhere hidden in the house as far as he was concerned this is the only way that the pipes around the back boiler could possibly be filling up,
however I have been pretty solidly updating this house over the last year and I am sure that there isn't, I have been in the loft and had most of the floorboards up and I am sure that there isn't a filler tank unless the previous owner was a bit special and did something mad like hide it behind a false wall or up the chimney.

so current theories are:

Plumber = hidden filler tank (honestly the only place I can possibly think this would be is either inside a chimney or under a floorboard but I haven't heard any filling noises so I am sure it can't be this)

My theory 1 = The calorifer has split inside the hot water cylinder which is how water is getting into the pipes around the back boiler, the water tank is less than a decade old but the fireplace is one of those Parkray 1970s things, I am thinking the previous owner maybe lit fire and there was some air in the system which ruptured the pipe. (if this is the case I am amazed I haven't had some horrible illness though)

My theory 2 = (long shot) the pipes from our hot water tank go next door which is where the filler tank is (we live in an ex council house semi so who knows what bodge jobs have been done over the years), although I doubt this as the houses are clearly two separate properties from the beginning so i can't see the benefit of one filler tank for two houses.

if this isn't clear then I will try and draw a diagram, I just wanted to know if anyone has come across this setup before or has any other ideas?

 

[Newboy]

Primatic cylinder

 

[Nige F]

I live in a 1940s semi, the only source of heating I have in the house is a hot water cylinder with an immersion heating the water, no pumps for the hot, just gravity feed

Coming off the hot water cylinder is the normal cold in, hot out,

Follow the "cold in " pipe - it must go to a cistern somewhere.

 

[ianmcd]

as already advised sounds like you have a primatic cylinder

 

[HERTS P&D]

Get an 'old' plumber.

Andy

 

[FiremanT]

Struggling to fully understand your OP.

Have you a large CWST and a small header tank? You have isolated and emptied the CWST? If yes to both, then you probably have a holed coil in the cylinder.

If you only have a CWST and NO small header tank, then you probably have a Primatic.

or do you have one of these:
Can you post a few pics, especially showing the F&R from the cylinder. Is there a label on the cylinder.

 

[zhuffzilla4]

Thanks for all the responses - sounds to me a bit like the plumber who came out was over egging his "years and years of experience"
FiremanT the tank is pretty much the same as the one you posted - I have taken a picture here
https://photos.app.goo.gl/8VQm4t4CRpAeM6g37

There is no sticker on the tank but when we got the house the person said it was installed in 2012-13. there are no other tanks in the house.

Follow up question is that if I do have a Primatic/mainsflow then do I just go and get a couple of stop ends, drain the water tank and stop off the feed/return from the fireplace and job done? , the plumber quoted a two hour job and wanted a minimum of £120 which seems a bit steep, I even offered to drain it for him before he came over but he said that wouldn't make any difference to the job price.

 

[FiremanT]

Not in a position to answer fully at the moment. But DO NOT cap off pipes leading from boiler.

 

[zhuffzilla4]

Just to try and make it a bit more clear I have drawn a quick diagram,

https://photos.google.com/share/AF1...?key=VDJDam44b1A0UHVPTUhJNjl3V2NuMW52dGJaZ3FR

I want to completely remove the radiator, fireplace and all pipework connecting to that circuit leaving only the mains water in, overflow and hot water to taps.

Am I safe to just to drain the cylinder, drain the tap at the back boiler and then be safe to remove the pipes connected to the cylinder?

new questions before I nip to toolstation is : if I am blocking the holes at the cylinder do I just block off the bottom hole or both?

the pipes coming to / from the fireplace seem to be 28mm - do I just need a 1" brass flange plug to plug this hole like this: https://www.toolstation.com/shop/p75541

or do I need something like a compression end (sorry I get totally confused between plumbing supplies switching between metric an imperial)
https://www.toolstation.com/shop/p50743

Thanks so much for all the help everyone has given so far.

 

[Hugh Jaleak]

No, take Fireman T's advice, DO NOT cap anything until you know exactly what you are dealing with. I'd suggest you may have a Single Feed 'Primatic' type cylinder there, if you wish to dispense with any type of external heating for the hot water, you may well have to change the cylinder.

Primatic's are designed to do away with the need for a separate Feed and Expansion cistern, the internals allow the Primary side, (Boiler, CH and HW circuits), to be filled and provide expansion room within the cylinder. You cannot disconnect the pipes as you wont be able to isolate them without draining the cylinder as well, (leaving you with no hot water!)

Capping the pipes and sealing off the internal workings could possibly leave you with a potential bomb. I think your Plumber is out of his depth, you need someone who understands these cylinders!

 

[Nige F]

You have a Fortic cylinder - with the cold cistern on top - you Probably have a direct one, because of the open fire back boiler,which has a cast iron water jacket. You Should have a cast iron rad in the bedroom. All this is because you don't need a calorifier with a direct system IF cast iron is used. The solid fuel boiler Does need to be de commissioned properly.

 

[Dan Robinson]

Pictures will help.

We took out a bank boiler years ago in a house where there was a small galvanized cistern tucked up under the stairs leading to the second floor. We only saw it because second of the ceiling underneath was hanging loose.

Great fun that job

 

[FiremanT]

I am attempting to remove an old condemned stove with a back boiler but when I drained the pipes going into the back of the stove the water wouldn't stop draining, and when I checked the hot water cylinder I could see it was refilling.

Please explain exactly what you mean / saw

 

[zhuffzilla4]

Please explain exactly what you mean / saw

Hi FiremanT, thanks for sticking with this,
just to clarify this is the pipework at the side of the fireplace downstairs https://photos.app.goo.gl/dcMeaB8RsSuvx14R7
the 28mm pipes go upstairs and are connected directly to the water cylinder the smaller pipes go to a radiator in the bedroom

I hooked up a hose to the drain tap by the fire and opened it up, let it drain for about 15 mins and water was still coming out, the pressure wasn't huge but there was still a decent flow of water coming out, far more than should have been in the back boiler, rad and pipework,

I went upstairs to the water cylinder and noticed the top cistern was filling up, I turned the drain tap off next to the fireplace and the cistern stopped filling straight away so there is clearly some kind of auto top-up going into the back boiler circuit.

I did speak to a plumber yesterday who offered to just cap the feed/return for the back boiler at the point of the water cylinder but he admitted that he hadn't really worked with primatic stuff before, and as someone earlier mentioned that not knowing what you are up to could be lethal I am still on the search for someone who is experienced in this sort of thing.

Also just for clarification - this house was owned by the council and was purchased by the previous tenant about 10 years ago although she told me she had been in the house for about 40 years, I don't think that the house had been updated in any way for at least 10 years so it is likely that any major work in the house is likely to have been done by the council.

 

[FiremanT]

Hi FiremanT, thanks for sticking with this,
just to clarify this is the pipework at the side of the fireplace downstairs https://photos.app.goo.gl/dcMeaB8RsSuvx14R7
the 28mm pipes go upstairs and are connected directly to the water cylinder the smaller pipes go to a radiator in the bedroom

I hooked up a hose to the drain tap by the fire and opened it up, let it drain for about 15 mins and water was still coming out, the pressure wasn't huge but there was still a decent flow of water coming out, far more than should have been in the back boiler, rad and pipework,

I went upstairs to the water cylinder and noticed the top cistern was filling up, I turned the drain tap off next to the fireplace and the cistern stopped filling straight away so there is clearly some kind of auto top-up going into the back boiler circuit.

Is the cistern filling via the ball cock?

Turning off a drain cock can not possibly stop flow somewhere else