Single pipe heating and radiators mounted too high

[edentech]

Hi Guys, I have recently had a new bathroom installed and have had a radiator mounted on the wall as a towel warmer. The bottom of the rad is about

3ft off the floor.

When I turned the heating on, the radiator did not heat up. My installers tell me that because I have a single pipe heating system and the rad is mounted so high up the wall, there is insufficient pressure to get the hot water into it. They claim that the water is simply flowing past the radiator and is unable to make it up there. I have bled the rad and there is water right to the top.

Is this a possibility? What other explinations are there? Could it be plumbed up the wrong way around (is that even possible)?

If this is true would it be possible to block the pipe flowing past the rad in effect forse the water through the rad? I know that this would mean that if I turned the radiator off, the whole system would break but are there any other reasons why this cant be done?

Thanks in advance.

David

[Dave Fawthrop]

|!Hi Guys, |!I have recently had a new bathroom installed and have had a radiator |!mounted on the wall as a towel warmer. The bottom of the rad is about |!3ft off the floor. |! |!When I turned the heating on, the radiator did not heat up. My |!installers tell me that because I have a single pipe heating system |!and the rad is mounted so high up the wall, there is insufficient |!pressure to get the hot water into it. They claim that the water is |!simply flowing past the radiator and is unable to make it up there. |!I have bled the rad and there is water right to the top. |! |!Is this a possibility? |!What other explinations are there? |!Could it be plumbed up the wrong way around (is that even possible)? |! |!If this is true would it be possible to block the pipe flowing past |!the rad in effect forse the water through the rad? I know that this |!would mean that if I turned the radiator off, the whole system would |!break but are there any other reasons why this cant be done? |! |!Thanks in advance.

My, pumped, single pipe system works fine. The TRVs on radiators and towel rails, also work fine, fitted to the upstream end. One towel rail has 2 ft pipe runs and the other, about 5 ft pipe runs.

[edentech]

Gutenberg

Free to any

Thanks Dave,

Any thoughts to what the problem might be and how to solve it? I know it's a difficult question to answer but is there anything I can look out for?

[TMC]

My understanding of a single pipe system is that all of the radiators are mounted in series along the pipe. these are not that common and are a cheap installation If the radiator in question did not heat up then none of the others would either.

I assume therefore that you have a twin pipe system where the radiators are mounted across the flow and return pipes. In this case a radiator can be turned off and the rest will still work normally.

Some idea as to where the boiler is in relation to the radiator would help (eg if the boiler is on the ground floor and the new bathroom is in the loft that may be the problem but if you live in a bungalow 3 feet of lift would never be a problem)

As to your problem you need to check that the valves are open at both ends of the radiator so that a flow through is possible. I would then turn off all of the other radiators in the house and start the system to see if the new radiator heats up Check also the settings on the pump you may be able to increase the speed

Tony

[edentech]

Hi Tony,

The boiler is on the ground floor and the bathroom is the next floor up. I have tried turning off all the other radiators but to no avail. I am yet to confirm that it is a single pipe system and will do so tonight by looking at the other radiators but I suspect that this is the case. I'm told that although the rad is linked up correctly to the pipe, the hot water is simply passing it by because it is too high up the wall.

[F]

No. They are effectively in parallel.

A single pipe carries water around the house and each radiator takes water from it and then returns it to it. The single pipe is 'unbroken' between each radiator's 'flow' and 'return' connection.

Turn one or more radiators off and the others continue to work as the water bypasses the radiators which have been turned off.

[F]

When a radiator is turned on in a single pipe system water flows through it because it offers a path of lower resistance than would be the case if there was just the pipe.

If your radiator is not warming then there must be unusually high resistance there. As previously suggested, check that the valves at both ends are turned on and try turning off all other radiators.

[TMC]

That makes sense it would also explain why on the only one of these I have seen there was only one valve on each radiator. It was an ex council place

Tony

[Dave Fawthrop]

|!On 16 Apr, 11:13, Dave Fawthrop |!wrote: |!> On 16 Apr 2007 02:58:05 -0700, [e-mail] wrote: |!>

|!> |!Hi Guys, |!> |!I have recently had a new bathroom installed and have had a radiator |!> |!mounted on the wall as a towel warmer. The bottom of the rad is about |!> |!3ft off the floor. |!> |! |!> |!When I turned the heating on, the radiator did not heat up. My |!> |!installers tell me that because I have a single pipe heating system |!> |!and the rad is mounted so high up the wall, there is insufficient |!> |!pressure to get the hot water into it. They claim that the water is |!> |!simply flowing past the radiator and is unable to make it up there. |!> |!I have bled the rad and there is water right to the top. |!> |! |!> |!Is this a possibility? |!> |!What other explinations are there? |!> |!Could it be plumbed up the wrong way around (is that even possible)? |!> |! |!> |!If this is true would it be possible to block the pipe flowing past |!> |!the rad in effect forse the water through the rad? I know that this |!> |!would mean that if I turned the radiator off, the whole system would |!> |!break but are there any other reasons why this cant be done? |!> |! |!> |!Thanks in advance. |!>

|!> My, pumped, single pipe system works fine. The TRVs on radiators and |!> towel rails, also work fine, fitted to the upstream end. One towel rail |!> has 2 ft pipe runs and the other, about 5 ft pipe runs.

|!Any thoughts to what the problem might be and how to solve it? I know |!it's a difficult question to answer but is there anything I can look |!out for?

I find out what is happening in my system with "hand Mk 1" Put a hand on the pipes and see what is hot and what is cold. Where does the pipe get cold, does this happen at a bend? It a swept T fitted the wrong way round?

[Andrew Gabriel]

They were very common in the '50's. They were not 'cheap', but the standard way of plumbing a pumped system at that time. Such systems required much more accurate radiator sizing than heating engineers are capable of nowadays.

Hum, I would say series, but with the plumbing equivalent of shorting fairy lights.

That's basically an on/off valve. The balancing is done per single pipe circuit with a gate valve, usually at the origin of the circuit.

[Lurch]

On 16 Apr 2007 02:58:05 -0700, [e-mail] mused:

The old rougharses way of fixing the problem is to clamp the main pipe inbetween the flow and return on the rad and force the water through the towel rail. This is most defintiely not recommended though.

As someone else mentioned, best bet is to see what is and isn't getting hot.

How well balanced is the rest of the system?

[edentech]

Gutenberg

Free to any

Hi Dave, I had a go last night and dug up most of the floor. I actually found that the pipe supplying the radiator was not hot either. It appears that my heating system is actually lots of little loops, the bathroom being the only radiator on this particular loop. The pipe feeding it comes out from the boiler, up into the loft, and back down into the bathroom. The pipe is only hot for about 4ft after coming out and up from the boiler before it starts to cool. I can therefore only assume that the water is simply not circulating around the circuit. What is it that pushes the water around? I can't see a pump anywhere on any of the loops.

I may actually attempt to take some photos for you guys to see because I'm no expert and I think there is something strange going on.

FYI, before the radiator was replaced there were two previously on this loop and they worked ok without a problem.

Cheers

[edentech]

See my pervious post. It seems to me that the water is not flowing through the supplying pipe sucessfully. The rest of the system seems fine but from my investigations it seems that they are running on seperate loops!

Very strange eh!

[Andrew Gabriel]

It might be that the length of pipe in the loft is air-locked and needs bleeding. Is there a bleeding valve on it?

The other possibility is that that circuit is designed for gravity feed (no pump), in which case it's not going to work unless you have the inlet to the top of the radiator and the outlet from the bottom.

[Dave Fawthrop]

|!In article , |! [e-mail] writes: |!> Hi Dave, |!> I had a go last night and dug up most of the floor. I actually found |!> that the pipe supplying the radiator was not hot either. |!> It appears that my heating system is actually lots of little loops, |!> the bathroom being the only radiator on this particular loop. |!> The pipe feeding it comes out from the boiler, up into the loft, and |!> back down into the bathroom. The pipe is only hot for about 4ft after |!> coming out and up from the boiler before it starts to cool. I can |!> therefore only assume that the water is simply not circulating around |!> the circuit. What is it that pushes the water around? I can't see a |!> pump anywhere on any of the loops.

We need more information. Is there a pump and where.

|!It might be that the length of pipe in the loft is air-locked |!and needs bleeding. Is there a bleeding valve on it? |! |!The other possibility is that that circuit is designed for |!gravity feed (no pump), in which case it's not going to work |!unless you have the inlet to the top of the radiator and the |!outlet from the bottom.

On gravity bottom inlet and bottom return also works, The water circulates

*inside* the radiators

[The Natural Philosopher]

been there, done that.

In my case shutting off every other loop and running the pump at max blew the gas out of its arse satisfactorily.

[John Stumbles]

When it gets into the bathroom does it go just to one end of the radiator or does it split with one branch going to one end of the rad and the other branch going to the other end of the rad and joining with that one to return to the boiler?