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One Pipe Central Heating System

Postby james29 » Wed Aug 27, 2008 12:47 pm

Hi there.
We have a one-pipe central heating system with brand new radiators and condensing boiler. As its a one-pipe system however, we cant put Thermostatic Valves on the radiators so cant regulate the heat of them. Hence, upstairs is boling hot and downstairs (esp the hallway) is freezing cold. (We cant have cavity wall insulation in our house).
Does anyone know of a way maybe of varying the radiator heat per room?
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Postby AdamsHeating » Wed Aug 27, 2008 5:44 pm


You should have lock shields valves, these can be adjusted to give an even temperature across the house. It's a case of trial and error unless you have a machine that will tell you the temperature at the inlet of each rad.

Most likely the valve on the radiator closest to the boiler will be almost closed and the radiator furthest away will be fully open.

Not ideal a open pipe system.

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Postby htg engineer » Wed Aug 27, 2008 7:40 pm

Change to a two pipe system with TRV's, I wouldn't recommend anyone using a one-pipe system these days - it's best to upgrade when you renew the boiler.

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Postby kevarch » Fri Sep 05, 2008 2:15 pm

make sure the radiator valves are of the full flow type. standard valves will not heat the radiators to anything like their full potential
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Postby mazfg » Tue Sep 23, 2008 9:52 pm

I too have a single pipe radiator system and have just fitted TRV's to it and they all work fine. How exactly is your one pipe system configured?
Is it that the pipe goes in one end of the radiator and out the other, if so I can see this not going to work for trv's.
My pipe goes into the radiator via a T-piece with one side going to the TRV (and then the radiator) and the other side to a length of pipe that runs along the bottom of the radiator. At the other end of this pipe there is another T piece which has the lockshield one side(which goes to the other side of the rad) and pipe the other which then goes off to the next radiator in the system. It then repeats like this throughout the whole system. This way if the TRV turns the radiator off, it allows the hot water to run along the bottom pipe feeding the next radiator and so on.
Hope this helps...check your system out?

Would be interested to know your set-up. Not a lot of info around for one pipe systems. I must say though mine does work exceedingly well and have never had any problems with it!
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