One pipe system woes

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11 Mar 2013
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Lancashire
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Dear All.

I fully appreciate that the real answer to this question is to repipe the system with two pipes. This would be something that I would plan for next summer, but for now I need a quick fix.

Last year I searched around for a firm to fit me a condensing combi and a two pipe system. I originally had a one pipe system connected to a Baxi back boiler and hoped that someone would take on the job. Whether or not there was an ample supply of work in my area remains to be seen, however not one firm seemed interested at all and either priced me above and beyond or just never bothered to get back to me. However, a friend of a friend who can now only be described as a complete clown offered to have a look and I now have an issue with the work that he did. I know that I should have gone back to him, and that I did - only to be shrugged off, told to go away and ignored ever since. Issue being, this was a foreigner, a cash job and I have no legal standing. I have threatened to contact the firm that he works for. However, what would that solve? I still have the issue that I will explain below.

He insisted that he could fit a combi in a bedroom, and could pipe it to the one pipe system. He used the old gravity fed water pipes and joined in at the loft, feeding the original radiators, leaving the old boiler in place (the fire is still connected and works). Initially the rads would not get warm and he believed that this was due to the pump on the boiler working so fast that it was racing around the system, under each rad, failing to enter and only heating up the old 22mm pipe. Reluctantly and against my better judgement, he cut the pipes underneath each rad so that the water was forced to enter each and every rad in series. Sounds awful, but the heating worked great. He fitted a Potterton Apollo Boiler incidentally.

Since then, I have converted a bedroom into two rooms and need a rad in the 'new room'. Today I have hung a small double rad, have piped it in 15mm plastic and have fed it from the flow and return 22mm in the loft, about 15 feet away from the boiler. The heating bled up, runs fine and all of the rads get warm bar the new one. Only a very small portion of the feed pipe to the rad gets warm in the loft and no amount of bleeding and messing about cures it.

I assume that the free flow of the one pipe system again is allowing the water to flow in the easiest direction (it is racing past the branches that I have fitted)? Without repiping at the moment, how can I persuade the water to flow along my new branch? I have considered fitting a 22mm stop cock/tap into the 22mm flow somewhere near to my branch to slow the water down, but fear that I may damage the boiler or put the pump under too much pressure.

Please don't ridicule me. I know I have made a mistake, but it was the only way I could get a combi fitted. I have a basic knowledge in plumbing - my dad is a retired plumber and I have worked with him off and on over the years.

Can anyone help me get this rad warm? We are foster carers and need that rad to work until at least the time where I can afford and/or have the time to do something about it in the warmer weather.

Sorry for the long post. John.
 
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Hi John, I'll have a go.

but first you have to forget the rubbish you posted based on ignorance.

A properly installed one pipe system will work wirh any boiler.

The real problem now is knowing what the idiots have done to mess it up and how you have connected the new rad.

Trvs must be the right ones and not the cheap every day stuff you can use with a 2 pipe system.

Ok back to the problem can you post a line drawing showing the pipes and rads.
 
I understand the problem.
What the guy did to pump it through each radiator certainly worked
so your piping is wrong for the new radiator.
Converting a system to two pipe is fairly straightforward assuming it
is easy to get at all the piping. I would estimate 2-3 days on an average house. I have done complete installs in only slightly more than this.
So get someone in and have it done while th weather is reasonable.
 
Hi John, I'll have a go.

but first you have to forget the rubbish you posted based on ignorance.

A properly installed one pipe system will work wirh any boiler.

The real problem now is knowing what the idiots have done to mess it up and how you have connected the new rad.

Trvs must be the right ones and not the cheap every day stuff you can use with a 2 pipe system.

Ok back to the problem can you post a line drawing showing the pipes and rads.

Mmm.

Diagram? Maybe not.

The system (from new in the 60's) is two pipe upstairs. The 22mm flow and return go into the loft from the boiler in the bedroom and then disappear into the dorma (its a dorm house). The flow goes down the chimney breast, through the old b/boiler, through each rad downstairs and then back into the dorma up the soil stack in the kitchen - where god knows what happens to make it a two pipe 15mm arrangement. It has always been like that. This is all original piping.

Worthy of note is the fact that all of this part of the system works fine. Its when I have tapped into the 22mm flow/return that I do not get a flow to the new rad.

FYI, I have removed the TRVs to rule out that issue.

Thanks in anticipation, John.
 
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As you have a section of the one pipe piped in series through the rads then balancing is going to be difficult.

Mebbe you should have piped it in series also.
 
I understand that. However the system works quite well. Granted I have no TRV's and so the heating is a bit - on or off. But as I said, the boiler works great, rads get lovely and hot, house is warm and my gas bills have plummeted.

It just that one rad I need help with - the new one.
 
Its not easy making a silk purse from a pigs ear. :LOL:

A diagram would be interesting.
 
Its not easy making a silk purse from a pigs ear. :LOL:

A diagram would be interesting.

A diagram is going to be essential.

As I read it the flow and return from the new boiler go into the loft.

Then I guess there's a length of pipe meaders around the building picking up all the rads as it goes. ( that makes it a one pipe system)

What worries me is the connection with the old back boiler if he's connected the new boiler into the primaries.

As a clue for the op. The flow into the rads are by gravity, therefore if it is a one pipe where you've connected, then the flow to the rad should raise up a couple of feet (min) first before dropping to the rad.

Lots of ways to sort it but need pics and drawings
 
Its not easy making a silk purse from a pigs ear. :LOL:

A diagram would be interesting.

Your right - it would. However I can't draw what I can't see!

Draw what you can see, it may make sense

Your loosing me on the primaries etc etc.

It is connected at the one pipe start. 15 feet away from the boiler.

I would try to draw you a diagram but I would seriously struggle as the vast majority of the upstairs is all hidden. I wouldn't even hazard a guess as to how it turns to two pipe.

Sorry!
 
Sorry, you said he used the old gravity fed pipes, assumed they were the two pipes going to a cylinder, which would have no connection with the heating outside of the boiler. ( this is the problem we need to sort.)

Dont even try to hazzard a guess how it goes to a two pipes. It doesnt and cannot other than through a manifold or LLH. (very unlikely)

I think he's taken the flow and return pipe into the loft from the new boiler, what he's done then is anyones guess.
 
Sorry, you said he used the old gravity fed pipes, assumed they were the two pipes going to a cylinder, which would have no connection with the heating outside of the boiler. ( this is the problem we need to sort.)

Dont even try to hazzard a guess how it goes to a two pipes. It doesnt and cannot other than through a manifold or LLH. (very unlikely)

I think he's taken the flow and return pipe into the loft from the new boiler, what he's done then is anyones guess.

Thats what he says he has done. He could not plumb directly at the back boiler as it is on the other side of the house.

My old system used to get slightly warm when the hot water was heating (due to the gravity side of things I believe). For that reason, he has removed the primatic cylinder in the loft, and has fitted the flow and return pipes (he says) to the old hot water pipes?

Seems odd to me but may mean something to you!

Must admit, he has connected to two existing pipes in the loft - and there were no heating pipes up there originally!!
 
Sounds like he has connected the new boiler flow and return to the old gravity (primary) pipes that feed back to the old boiler, then through the old boiler for the heating.

If that is true then if you have also conncted into the same two pipes then your rad should work, Is there a means to get the air out off the new rad pipes at high level ( perhaps one of them is air locked

Where is the pump now.
 
I was always taught that when joining into a one pipe system, no matter where, tees should be rad distance apart. For instance, if you have one pipe system running through loft space and you hang a 600 rad in room below, tees should be min 600 apart.
Injector tees would help.
 

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