Radiator Outlet Temperature

Radiators *dissipate* heat - they don't *generate* it!

Whichever side is hotter is the *inlet* (flow) and the cooler side is the

Although it is *usual* to have lockshields on the return side, it doesn't really matter. If any/all of the other valves are TRVs, make sure they are designed to operate with the flow in either direction. Ordinary manual valves don't care, anyway.

You can address this very easily by swapping lockshield caps with the wheel valve knobs.

In reality, it doesn't really matter.

...unless the ambient temperature is higher than the CH water temperature!

Thanks for the answers, that is preety much what I suspected from reading about it, I guess the system would need balancing after swapping them over, as I turned them all to fully open!!!!!

Dean

I would just add to the other replies by saying that depending on the valve types this may have been done for a reason. In the case of my own CH system the instructions for the Danfoss TRV's said that they had to be mounted with the barrel horizontal if fitted on the flow but if vertical mounting was required they should be fitted to the return, and that was how we did it with all the lockshields on the flow side.

Peter.

Not unless it already needs it ;-)

With many manual valves they are in fact the same mechanism as a lockshield. Typically when you buy one, you get two plastic caps for it. Fir one, and it is a conventional valve, fit the other and it is a lockshield. If yours are like this, then you ought to be able to swap over the plastic tops without even changing the valve position.

True - but I had discounted that possibility!

Except that what was a lockshield - carefully adjusted to give a balanced flow - now has a handwheel and can be turned willy-nilly. Equally what was the on/off valve is probably fully open and no longer balanced.

So YES, the system *will* need re-balancing.

I did say ""without even changing the valve position".... ;-)

(must admit I did not follow the thought through as far as the possibility that someone may want to twiddle with the knob!)

In which case, try the following procedure:

Having swapped the knobs, close the manual valve completely and count how many turns are required. Now close the lockshield valve completely and count how many turns that required. No open it the same number of turns as the other valve was open. Finally open the manual valve the same number of turns as the lockshield was open. Balance restored, all is right with the world, and you can twiddle with your knob whenever you fancy. ;-)

That will probably get you somewhere close - assuming that the valves are identical apart from the heads. [If they're not, you probably won't be able to swap heads anyway].

Also, you need to plan this in advance. The OP appears to have opened the lockshields fully without noting their 'balanced' position!

Well, I have swapped them over, the lockshield valves are on the correct side now! They were not opened fully when I took the covers off them, not really sure how the system was balanced before!? The house is about 30 years old and the valves have bigish brass bodies (i.e. They look like they could have been the original ones). It's all very bizzare! I'll fire the system up tomorrow to see how well it is now!

Thanks everyone for all the help Dean.

Sorry this is a bit late, but in so many replies I'm amazed only "Set Square" noticed you already upset the balancing (in the unlikely event that they were ever properly balanced anyway), and even he forgot to tell you how to redo the balancing. See the chapter on "Balancing Central Heating Systems" in the FAQ.

Phil The uk.d-i-y FAQ is at