Help required with One Pipe system TRV's

[james7777777]

Am fitting new rads in my house which has a one pipe system. I have gone out and bought myself a set of danfoss one pipe TRV valves at great expense! Here they are:

RA-G Valves Without Pre-Setting.
However instead of having a compression fitting to plumbing in the 15mm copper pipe it has a 1/2 inch female screw thread. Is this the right valve for domestic usage???

 

[jackyp1234]

put a male iron to copper in them

 

[ecowarm]

You may have got the wrong ones for the job, they are commercial for a gravity one pipe system.

 

[james7777777]

OK Thanks - They are so bulky I wanted to make sure they are OK for the home!

Also I looked at some honeywell TRVs today that didnt have the tiny hole that most TRV's have that restricts the water flow. It didn't say they were anything but "standard" TRV's however the bore of the honeywell's doesnt look that much smaller than the specialist Danfoss TRV valves - do you think I could get a away with the Honeywell valves?

 

[james7777777]

hmmm - I have a domestic, pumped one pipe system...however i cant see any other specialist one pipe valves in exisitence???

 

[tamz]

You have bought the correct valves. They are of a more commercial design as these days one pipes are found on commercial rather than domestic.
You can fit Ras -C or D heads instead of the bulky ones.
Either use a half inch x 15mm male iron or a half inch internal nut and ring.
Danfoss do them - code 013G4115

Drayton used to do one but i'm not sure if they still do.

 

[ecowarm]

be careful some 1 pipe systems are not suitable for TRV's at all

 

[james7777777]

Ecowarm - Im no expert but I dont think thats true. These Danfoss valves are specifically manufactured for one pipe systems

 

[james7777777]

Thank you Tamz

 

[ADM360]

I belive ecowarm is correct! that some one pipe systems are not sutable for TRVs as the rads are piped in series so if the first rads TRV shuts down there is no flow though to any other rads!

 

[ecowarm]

Thats correct ADM

 

[ecowarm]

Ecowarm - Im no expert but I dont think thats true. These Danfoss valves are specifically manufactured for one pipe systems

Taken from the website that your link above sends you to,

RA-G - for 1-pipe systems
For use in conventional 1-pipe systems, where circulation through the radiator relies on gravity. RA-G valves have capacities optimised for this type of system which require high flow rates at low pressure drops to function correctly.


It will not work correctly on a pumped system!

 

[ASJ]

I belive ecowarm is correct! that some one pipe systems are not sutable for TRVs as the rads are piped in series so if the first rads TRV shuts down there is no flow though to any other rads!

I think it depends on how the one pipe system is configured. In mine the one pipe is a continous, unbroken, loop with each radiator teed off the loop(for flow) and back into the loop (for return), thus if the valve is shut down the water simply bypasses that radiator and carries on to the next one. The radiators are not really in true series because if they were then as you correctly stated, closing one would stop the flow to the next.

 

[Unregistered]

I don't care that this is an ancient thread, I don't care it's an ancient thread.

I'm just going to annoy you all on it anyway. ..

 

[Best]

Try registering with the forum and start a new thread, although what you say doesn't make any sense.