trv single pipe system

[cardiy]

HiHi Have viewed this topic before but still not clear. I have Drayton trv never fitted I think its a trv3 or even 2 as its not got black rubber under thermostat. Anyway it has full diameter holes on the in and out and is flow one direction only, it looks to me to give identical flow to a manual shutoff as fitted to my system, if that is the case the flow should be OK but will the the thermostatic control work? I can't work out from posts what is being said is it flow or control that's the problem, it seems that most modern trv have restricted diameters and you have to pay through the nose for a full diameter flow. I have seen Evolve trv pictures which seem to have full diameter holes if so will these work on a single pipe system. Mine works well but need controls on some rads. Please can someone clarify.

 

[PhoenixServices]

Be careful with fitting trvs to a one pipe, depending on how it is piped up it could stop all rads from working when it shuts off. You can check this by turning the rads off that you want to fit the valves to on the lock shield. If the rest of the system still works, you are fine to fit trvs.

 

[Riley]

As above and I wouldnt guess if the TRV you have isn't specifically for a one pipe system most companies do a version. Something like Danfoss Randall RA-G Single Pipe TRV Body

 

[cardiy]

Thanks for replies. It seems that big manufacturers have gone over to restricted inlets to make balancing on modern systems easier whereas their original models were just auto versions of manual valves. So if I can find full diameter trv by some manufacturer who still uses the original concept will they work. I don't want to pay a big price because there is a premium on low volume sales. A quick scan of images on the net does show some with full diameter connections. I am diy but done full systems on previous houses so not muppet, this system already in this one.