Pressurised system

I had a combi boiler installed last year (May) all the rads apart from 1 (bathroom) have thermstsat valves fitted, on 2 of the rads upstairs I noticed that the plumber had put the stat on the other end of the rad where the TRV had been ????? surley to be able to balanace the system the stats should all be at the same side of the rads.


How easy is it to install a new rad and /or replace an existing rad on the system. do I have to drain down as with a header tank/ pumped system

if the TRV's are bi -flow then you will be ok, but some 'bi-flow' TRV's need adjusting (Danfoss RAS-C2 for eg). look at your TRV bodies and see if there are any arrows on them, a single ended arrow means one way flow and a double ended arrow means bi flow.

They are probably biflow due to the age of the system.

Are you having probs with your central heating?

yes mate the old pumped system had the main circuit running under the floorboards upstairs with 3 downpoints feeding (1) living room back rad (2) living room front rad and the (3rd) feed ing the hall and dining room the system was well balanced as I drew on knowledge from this site on adjusting the trv's so that the last rads on the system were hot, unfortunately this does not happen with the combi boiler the rad in the hall and diner (3rd) downpoint always seems cold, dinig room rad is warm to touch at the top but cold at the bottom same as hall rad

warm at top and cold and bottom means that the TRV has turned off at a set temp or sludge.

turn all other (working) rads off and see if the prob rads get hot, if so then you may well need to balance system, if not may have bad pipework installation/sludge etc...


and when balancing the rads\system adjust the lockshield valve and not the TRV end