want to install a new radiator in single pipe system

[Margi]

Hi all
I need some advice. Ever since I changed one of the radiators in master bedroom (middle of single pipe system) the others do not work that well. I have to keep balancing still some of the radiators are not heating well.
I want to change the two other radiators in living room (very old ones) to new and keep the single pipe system. It is a 2 bed flat with 6 radiators.
Which radiators are better for single pipe system? and what do I need to consider before doing this? I would not personally do it but most of people I have spoken to do not know much about single pipe system hence the recent radiator in the bedroom not fitted properly.
Thanks

 

[ShaunCorbs]

dont mess with one pipe systems sorry but your asking for trouble it you start changing things

 

[rocketmanbkk]

dont mess with one pipe systems sorry but your asking for trouble it you start changing things

Can you explain why please SC?

 

[ShaunCorbs]

Can you explain why please SC?

they tend to not work like above when they get messed with and you can never get them working right if you do , and there sludge traps

 

[jonnyswamp]

If you change any rad on a one pipe, make sure it is identical in length, as if you have to alter pipe tails to suit shorter or longer rad you will have trouble getting things working properly
if you do alter length of rad, you will have to expose the "ring main" and cut in tees so that feed to rad valves are vertical from the main up into the valve without any change in direction
On these systems the heating water is pumped around the ring main (one single pipe travelling around the property) and heat is rises up the feed pipes into the rads, rather than getting pumped through like a standard system

http://www.gasman.fsbusiness.co.uk/images/Onepipe.jpg
If the above image is visible, you'll see the pumped water will take the path of least resistence, so won't get pumped through the rads, just relying on the laws of physics to allow heat to rise and cooler water to fall back into the ring main, which is why the feed pipes must be vertical to work prperly
Don't know how much sense that has made to anyone,but it makes perfect sense to me
No doubt someone else will be along to explain it in half the words and make 3 times as much sense

 

[Roger Welton]

Also if you increase the size of a rid at the start or in the middle of the loop, you will reduce the heat output from the rest of the loop so should really increase them to compensate.

(or just convert it to a 2 pipe and it will never be a problem again)

 

[lame plumber]

or just rebalance the system as they did when it first went in, s'not rocket science you know

 

[jonnyswamp]

Depends if rad is different size to the one it replaced, also if rad valves have been replaced with modern TRV's

 

[Unregistered]

Thank you for all the replies-after rebalancing the system it seems ok except for the one radiator in the bathroom-pain!!
Would really love to convert the system to two pipe if it is under £1000 for a 2 bed flat.