1980's Radiators with only one valve

[George Kaplan]

Hi folks, I need to remove at least a couple of radiators in a house that I have recently purchased. I am not a plumber or heating engineer but I am an engineer (mechanical and hydraulics) so I am familiar with the way things work. However this house has radiators that I am not familiar with. The two pipes come into a block at the bottom of the radiator where one side seems to go straight into the rad and the other goes to the top of the rad via a pipe that connects to a TRV.

I need to remove two of them to work out why they are not heating up fully but cant see a way of isolating them. Before I drain all of the pipes can anyone on here enlighten me as to what these are and as an aside why would you use them. I think they date from 1981 when the house was built.

Thanks in advance, George.

 

[Deleted member 120897]

It’s a twin entry radiator valve/radiator, I’m not entirely sure how they work, but you may just be able to close off the trv.

 

[George Kaplan]

It’s a twin entry radiator valve/radiator, I’m not entirely sure how they work, but you may just be able to close off the trv.

Thanks for the reply. Closing off the TRV will not isolate the pipes. The pipe unions are before the TRV.

 

[snowhead]

Not seen them before but I'd guess they are Servowarm, they had some unusual heating systems.

Between the pipes at the bottom there looks to be a plastic bung.
That may be covering the (lockshiled) return valve, either screwdriver or allen key to turn it possibly.

If you want the radiators off the wall you won't be able to isolate, only drain the system

 

[Basher]

As all above, you'll need to drain the system.
I suspect if there's an adjustment behind the bung, it may be for balancing the system

you're not entirely alone
!

 

[George Kaplan]

Thanks all, I guess I will need to drain it down. The house has a void under the ground floor and so I was able to have a quick look at some of the pipework. It looks like at least some of the system is piped in series which is also not ideal. Maybe thats why the rads are as they are. I think I may try to live with it all as it is and then, next summer drain the whole lot down and flush the whole system and maybe re-pipe it in parallel. I will see how I feel when the time comes.

Thanks again.

 

[ShaunCorbs]

New valves won’t work with a series style eg 1 pipe

 

[Basher]

The house has a void under the ground floor and so I was able to have a quick look at some of the pipework. It looks like at least some of the system is piped in series which is also not ideal.

I was going to ask if it was a one-pipe system. That's why you have that arrangement.
I have a one-pipe system from about the 1960's. Everyone seems to dismiss one-pipe and want to "upgrade", but using the right valves, piping it with adjustable zones, and with balancing, it works absolutely fine.
You can get Caleffi valves designed for 1 pipe, with thermostatic valve and internal bypass, that have a similar twin input to yours, if you ever needed to add a radiator without doing a radical 'upgrade'.

 

[George Kaplan]

Hi Folks, I started this post some time ago and you guys were very helpful. However I have done nothing about my issue until now due to it being summer.

To recap, the property was built as a bungalow in 1980 and had a 1 pipe central heating system. At some point, I think in about 2007, te previous owners did a loft conversion to make it two stories and at the same time changed the layout slightly downstairs and re-did the original bathroom downstairs.

There are lots of radiators downstairs, 13 in total, all fed by the single pipe system all in 15mm. Only about half of them get warm. The first 4 get very hot, a couple more get warm and the rest stay more or less stone cold.

So I pondered my options and decided the best course was to re-pipe the system. This also means I can install two circuits downstairs so that I can separate the bedrooms from the living area. I decided to go with copper due to the potential for rodents in the circa 3 ft high crawl space under the ground floor.

Up to now I only had a quick look at the pipes closest to the access hatch which were all the original ones in 15mm soft copper. However delving further under the house it soon became apparent why some radiators stayed cold. I am guessing that the plumber that did the bathroom remodel did this to 7 radiators in total because all of the plumbing he (or she) did was in the same plastic and had no insulation. See the picture. What a muppet!

Also, I found a large pump under the house. It was fully disconnected but was obviously in use at some point as it was on a foam pad and I could see where it was wired up to in the past. Any ideas what this wold be for? I put the beer can in the frame for scale. There is a label under the end cover of the pump and using google, the label seems to refer to a pressure vessel.

I have some other questions but will start a new thread with them.

Thanks again,

George.

 

[Basher]

There is a label under the end cover of the pump and using google, the label seems to refer to a pressure vessel.

It appears to be a shock arrestor - here's a slightly younger version:

Also it looks as if those old rads are fitted with one-pipe valves with bypass, caleffi style, where the rads could all be connected in series, not Tee'd of close-together Tee's on the pipe, like you show under the floor, which won't work well (or at all)!

PS I don't know what that pump is for !!

 

[ShaunCorbs]

It’s a cold water pump

Tbh the heating wants to be ripped out and started again ideally new rads aswell to replace any old ones etc

 

[George Kaplan]

It appears to be a shock arrestor - here's a slightly younger version:
View attachment 84224
Also it looks as if those old rads are fitted with one-pipe valves with bypass, caleffi style, where the rads could all be connected in series, not Tee'd of close-together Tee's on the pipe, like you show under the floor, which won't work well (or at all)!

PS I don't know what that pump is for !!

Hi Basher, yes the system should be piped in series but the muppet who modified the circuit basically added a bypass at each radiator, no wonder they didn't work.

I am piping two new circuits in parallel in 22mm.

I have some questions about Controls but I will post a new thread when I get to that point.

Thanks,

George.

 

[ShaunCorbs]

That is actually how a one pipe circuit should be installed but with injector tees

 

[George Kaplan]

It’s a cold water pump

Tbh the heating wants to be ripped out and started again ideally new rads aswell to replace any old ones etc

Thanks, I did wonder if it were to boost the water pressure which isnt great here.

I am replacing all the pipes and creating three separate circuits so I can independently control different zones.

Some of the rads are being replaced now although some will have to wait until next year as I have a finite budget this year.

That is actually how a one pipe circuit should be installed but with injector tees

I didnt know that. I thought injector tee's were used with gravity systems.

However I have never come across a single pipe system before.

George.

 

[Basher]

George - I'm not a plumber as you've probably gathered, but thought you might be amused by my experience of 'one-pipe'.
I lived with a one-pipe system for over 30 years, originally with an oil boiler that sounded like the engine room of an ocean liner, replaced by a Potterton when gas arrived in 1990, then updated with a system boiler a few years ago.
Fortunately it had been designed with 5 'zones', so wasn't 23 radiators all on one pipe! Also some attention had been paid to how the rads had been connected, though there were no injector tees. The sort of thing below.

But in the process of "maintaining" it, I did come across the Caleffi valves that allowed rads to be connected literally in series
You can adjust the ratio of flow through the bypass to flow through the rad, so get them to similar and adequate temperatures, though as you see below, Caleffi suggest progressively bigger rads!


With a Honeywell Evohome programmer and motorised valves on most rads, it worked well.
I admit more trouble than a proper 2-pipe system, but it did the job!!

Best of luck with the improvements to your system.

 

[ShaunCorbs]

Thanks, I did wonder if it were to boost the water pressure which isnt great here.

I am replacing all the pipes and creating three separate circuits so I can independently control different zones.

Some of the rads are being replaced now although some will have to wait until next year as I have a finite budget this year.



I didnt know that. I thought injector tee's were used with gravity systems.

However I have never come across a single pipe system before.

George.

Be careful if re using existing rads as you will have to alter the pipework later as most likely be imperial sizes eg width/length of them

 

[George Kaplan]

George - I'm not a plumber as you've probably gathered, but thought you might be amused by my experience of 'one-pipe'.
I lived with a one-pipe system for over 30 years, originally with an oil boiler that sounded like the engine room of an ocean liner, replaced by a Potterton when gas arrived in 1990, then updated with a system boiler a few years ago.
Fortunately it had been designed with 5 'zones', so wasn't 23 radiators all on one pipe! Also some attention had been paid to how the rads had been connected, though there were no injector tees. The sort of thing below.
View attachment 84234
But in the process of "maintaining" it, I did come across the Caleffi valves that allowed rads to be connected literally in series
You can adjust the ratio of flow through the bypass to flow through the rad, so get them to similar and adequate temperatures, though as you see below, Caleffi suggest progressively bigger rads!
View attachment 84235

With a Honeywell Evohome programmer and motorised valves on most rads, it worked well.
I admit more trouble than a proper 2-pipe system, but it did the job!!

Best of luck with the improvements to your system.

Hi Basher, thanks for the comment. My existing system has Caleffi valves already. I have adjusted the bypass in them so that it doesn't work (on the rads that are not being replaced immediately) so that they work on the new circuit.


George

 

[George Kaplan]

Be careful if re using existing rads as you will have to alter the pipework later as most likely be imperial sizes eg width/length of them

Thanks for the tip. The pipes for all existing rads come up through the floor in pairs only about 2 inches apart. When I replace the existing rads I know that I will have to modify the pipes anyway and I am OK with this.


Having spent far too long in the crawl space the pipework is 99% complete. I just need a couple of fittings that I will pick up next week. Once it is all leak tested I will have to go back in and insulate everything.

When I was taking out the old pipes I noticed that most of the system was 15mm but one leg of the system was in what seems to be 18mm pipe which is a new size to me. Anyway its now all replaced with 22mm with 15mm tails to each rad.

George.

 

[Lou]

(Just bumping a few older threads, they will drop off what is new soon)

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