Balancing problems with Honeywell TRV's

[dbharrison]

I have recently fitted Honeywell VT117E TRV's on all my radiators except one (same room as room thermostat). After fitting I found I had a balancing problem as one of the rads did not get hot (unless all other rads were turned off and then it got propperly hot)). The TRV's have a built in balancing screw and I tried to use this to reduce the flow to each of the rest of the radiators and force it into the problem rad. This did not seem to be effective at all and I could see that even with the balancing screws set to the 'fully closed' position there seemed to be considerable flow through each of the TRV's.
Has anyone else had similar problems or am I doing something wrong here?

[fuzzy]

you normally balance using the lock sheilds on the return, is this possible?

take of all trv heads so fully open and run heating, balance each rad with LS, then replace all heads. Should only turn off when satisfied.

I have had a problem with some trvS IN THE PAST, some have a limiting piece of plastic internally, just flick it out, some just too sensitive! had to back of the thread to allow to open!

hope some of tis helps, let me know how you go on dbharrion

[dbharrison]

Thanks Fuzzy
Problem for me was that the valves on the rads (non TRV) were a bit of a mixed bunch and I could not tell which were Lockshield and which were on/off types. I have now gone round and replaced all the non TRV valves with Lockshield. The non-working rad now does work but I have found that I need to close all the other rads almost right down (about 1 turn open on the Lockshields) to get enough flow through it. Something has changed since putting in TRV's but I am not sure what

>mixed bunch and I could not tell which were Lockshield and which were on/off types

their is no difference between a lockshield and a wheelhead valve only the plastic cap.

>(about 1 turn open on the Lockshields)

thats all you need, a fully open valve is only about two turns any more after that and it doesn't restrict the bore if you look down a valve.

their is useally aprox 11 degrees difference between your flow pipe and return.

[CharterGAS]

11 degrees flow return differential on a non condensing system and 15 degrees difference on each rad

make sure you have 20 degrees minimum on a condensing system!!!!