2 metre long rad won't heat up

[D_Hailsham]

knowing what works and what doesnt.

If it does not work why do they specify it as the connection method when testing rads?

If something works in theory and in practice, but not in a particular case, that normally means that there is a flaw in the implementation. In the OP's case, the system is probably well out of balance, due to the addition of a 3-3.5kW radiator.

Also, the fact that the OP says that both pipes are very hot suggests that the LS valve has been left fully open. So the water will take the path of least resistance, i.e down the first few channels in the rad. Consequently, one side will be hotter than the other.

 

[mickyg]

knowing what works and what doesnt.

If it does not work why do they specify it as the connection method when testing rads?

If something works in theory and in practice, but not in a particular case, that normally means that there is a flaw in the implementation. In the OP's case, the system is probably well out of balance, due to the addition of a 3-3.5kW radiator.

Also, the fact that the OP says that both pipes are very hot suggests that the LS valve has been left fully open. So the water will take the path of least resistance, i.e down the first few channels in the rad. Consequently, one side will be hotter than the other.

thats wonderful, but er...it won't work properly. simples.

 

[Agile]

knowing what works and what doesnt.

If it does not work why do they specify it as the connection method when testing rads?

Also, the fact that the OP says that both pipes are very hot suggests that the LS valve has been left fully open. So the water will take the path of least resistance, i.e down the first few channels in the rad. Consequently, one side will be hotter than the other.

I would expect the connection method used when testing rads would be to the OPPOSITE top connection.

In the OP's case, I dont see that a reduction in flow rate will improje the situation, in fact I would expect just the opposite.

This is a classic case of a DIY job going wrong as a result of lack of experience. Luckily its just a matter of repiping it correctly.

Rony

 

[bengasman]

knowing what works and what doesnt.

If it does not work why do they specify it as the connection method when testing rads?

It isn't. Not in this century anyway.
Standard practice/recommended way of doing things: bottom either side.
Flow in at top on one side and return out at other side was not unheard of 40 years ago, and quite the standard in the victorian era. Things have moved on since.

 

[namsag]

As i said DHalisham google all you want but as jus about all on here who actually work on systems will tell you it just doesnt work on rads this size

 

[D_Hailsham]

knowing what works and what doesnt.

If it does not work why do they specify it as the connection method when testing rads?

It isn't. Not in this century anyway.

When rads were tested to BS3528, the connection method used was TBOE. When BS3528 was superseded by BS EN 442 (in 1997 - last century), the connection method was changed to TBSE.

Standard practice/recommended way of doing things: bottom either side.

I agree this is how the majority of systems are connected, probably for aesthetic reasons.

 

[mickyg]

I agree this is how the majority of systems are connected, probably for aesthetic reasons.

no because it works better. It might not say that when you search google, but in practice thats how it works best.

 

[bengasman]

I agree this is how the majority of systems are connected, probably for aesthetic reasons.

no because it works better. It might not say that when you search google, but in practice thats how it works best.

Damn, you beat me to it.
It's funny how you can read and google about things for years on end, those that don't have much practical experience, will never see what is obvious to those that do.

 

[holty]

BS EN 442 .just been to my friens house in holland were it is standered practice to have TBSE on small rads.yet the larger rads had TBOE.even the dutch figured out that larger rads using TBSE wont work properly.

 

[D_Hailsham]

In the OP's case, I dont see that a reduction in flow rate will improje the situation, in fact I would expect just the opposite.

It's a case of getting the flow rate correct; and this means getting the differential pressure across the radiator correct, which is done by adjusting the LSV.

Without knowing the exact changes made to the OP's system, e.g:

was it replacing other rads and what size, or an additional rad?
where does the new rad appear in the system?
what is the total kw of the system?
etc,

It is impossible to say why the OP is having problems.

 

[bengasman]

No wonder they worked it out, gets bloody cold up there. However true that may be, it is not common practice there to connect rads TBOE, not in this century that is.
TBOE is a relic dating from the days when gravity feed was the norm, and 2" pipes the standard. One step up from Roman times in other words.

 

[bengasman]

In the OP's case, I dont see that a reduction in flow rate will improje the situation, in fact I would expect just the opposite.

It's a case of getting the flow rate correct; and this means getting the differential pressure across the radiator correct, which is done by adjusting the LSV.

Without knowing the exact changes made to the OP's system, e.g:

was it replacing other rads and what size, or an additional rad?
where does the new rad appear in the system?
what is the total kw of the system?
etc,

It is impossible to say why the OP is having problems.

It may be complicated for you, for us that actually work in this field it is pretty simple; the method is unsuitable for this setup; as has been mentioned several times, the rad is too long for this to work.

 

[Agile]

It's a case of getting the flow rate correct; and this means getting the differential pressure across the radiator correct, which is done by adjusting the LSV.

It is impossible to say why the OP is having problems.

Getting the flow rate "correct" is solely a matter of producing the temperature differential appropriate to the BOILER's expectations.

The lower the differential the more heat output from the rad!

To me its quite clear that the OP has wrongly connected the rad and so its only heating at the one end.

Tony

 

[holty]

No wonder they worked it out, gets bloody cold up there. However true that may be, it is not common practice there to connect rads TBOE, not in this century that is.
TBOE is a relic dating from the days when gravity feed was the norm, and 2" pipes the standard. One step up from Roman times in other words

can only tell you what i saw in his house which was only installed 5 year ago and had recently, a remeha fitted.sorry rephrase that that larger rads were bottom opposite ends. still the smaller rads were TBSE.

 

[bengasman]

Exception that proves the rule; bottom either end is the normal way there, like in any civilised country.