Over the last approximately 15 years we have found it impossible to get all the rads to heat up without shutting off the rads in rooms not being used.2 years ago we had a new Glow worm Flexicom hx 24KW condensing boiler fitted the old one was a 50,00 btu so I thought all our problems would be over.Wrong we still couldnt heat all the rads.There is TRV's on all rads 9 in total there is no room stat or cylinder stat.The C/heating pump had to be changed last November.I have been told by a plumber that the original system was a one pipe system and the new rads have been piped as a two pipe and the rest has to be changed and a valve put between the flow and return.Can anyone advise me if this is the best option.He will be fitting a cylinder stat and another zone valve so I can have water only or C/heating only or both at once.Just one more bit of info the original cylinder was a primatic and when it needed changing I had a header tank fitted and an ordinary cylinder.
One to two pipe C/heating system
- Thread starter deden56
- Start date
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two pipe system is always better
A one pipe system is not suitable for your new boiler - you can never mix have a mix of the two systems because it won't work.
Here's the difference -
On a one pipe system the water in the return from the 1st radiator goes on to warm all up the other radiators (in turn) before returning to the boiler to be re-heated.
On a two pipe system the water in the return from each individual radiator goes directly back to the boiler to be re-heated.
As you can see the systems are completely different and therefore totally incompatable.
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Sure you can mix, but as you've seen it isn't a great idea. Going completely over to two pipe will probably solve your cold radiator issues.
You also should consider a room stat since you're making all those changes.
You also should consider a room stat since you're making all those changes.
But was it all flushed and cleaned out @ the time
could be sludged up still ,The system has not been flushed but when it was drained about 10 times over the last 10 years it was very clear.How can I tell that the system is a 1 pipe and needs changing? has been drained 3 times in last week.
I found that the heat exchanger was blocked and this caused the boiler to tripped out and show a fault. Thanks to a local plumber this was diagnosed and sorted in a few days
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