Switching manual control value and lockshield around?

[richardadc]

I'm about to fit some TRV's and ideally on some of the radiators i need to fit them on the side the lockshield is rather than when the manual control valve (MCV) is. Can i just remove the plastic turn knob from the MCV and and then adjust this to be open by the same amount of turns as the current lockshield (to balance the system as before). I would then obviously replace the lockshield with the TRV.

Please let me know if this would work?

 

[heatingeng]

yes and no.

trv,s are better to be placed on the flow although some are designed to work on both the flow and return.

 

[Whitespirit66]

Yes, that will have the same effect.

Just make sure you but bi-directional TRVs if you are fitting some on the return side of the rad.

 

[D_Hailsham]

trv,s are better to be placed on the flow

Why?

 

[heatingeng]

trv,s are better to be placed on the flow

Why?

because in a lot of the older trv,s it says in the instruction to fit on the flow .
and you get a better control if there on the flow in my opinion.

if there on the return they will turn the rad off after its already got hot giving less control on the temp .

but as i said some manufactures will say you can fit them on the flow or the return and some will just say flow.

 

[richardadc]

Thanks all. They're Honeywell VT200e's so they are bi-directional. Where possible though i will try to fit them on the flow.

 

[D_Hailsham]

trv,s are better to be placed on the flow

Why?

because in a lot of the older trv,s it says in the instruction to fit on the flow .
and you get a better control if there on the flow in my opinion.

The original, one way flow, TRVs had to be fitted on the return with the adjuster vertical and with it horizontal if fitted to the return.

if there on the return they will turn the rad off after its already got hot giving less control on the temp.

But a TRV is not a switch, which turns the rad on and off. It is a proportional control. When the room is below temp it will be fully open. When the room temperature is within about 2 degrees the TRV will start closing down. When room temperature has been reached the TRV will have closed down just enough so that the heat given off is enough to maintain the room temperature. If the TRV is acting like a switch, it's because the system is not properly balanced.

Some people do say that, if you fit it on the return, the water temperature has less effect as it is colder; but I haven't seen any evidence to substantiate that.

 

[heatingeng]

when designing central heating good pratice is to fit any control on the flow to give best results .
i have been to a number over the years and in my own house we have a trv on our toilet rad the room is always very warm in there even if you turn it down to 2 or 3 because of the reasons given.