Thermostatic Radiator Valves

[MrsMaria]

I have TRVs on the majority of my radiators. Does it matter whether they are on the inlet or outlet of each of the rads?

[buildersmate]

Yes, it does.
Look on the body of the TRV for an arrow like a left left sign - it will show the direction of water flow required. Modern ones are often dual-direction and have a double-headed arrow to show this.
The thing won't work properly if you have a single-direction one with the waterflow the wrong way.

[MrsMaria]

Thank you for this. The TRVs are Danfoss and are fairly new (installed last year), where should I be looking for the arrow symbol? If I need to take the plastic top off, how do I do this?

[tezestwing]

can you tell the flow and return from your pipe work ? If you are not sure how to then i would have some advice from someone that dose,TRVs can play up if you dont know how to deal with them.
BM is quite right but to be a bit more precise the arrow is embossed on the actual metal casting --> as opposed to stamped also on the older ones before yours I think ,the head of the TRV was on top or to the side to satisfy flow conditions are yours like this ? I would leave the top alone Mrs M hth Tez

[MrsMaria]

Thank you Tez. I am able to tell the flow on the rads, input is hotter than output. TRVs are on input on some rads, output on others, and plumber who installed them reckons he's balanced them but most are cold at the bottom except if the boiler is going full blast. It's because I have no faith in the plumber that I posted my question (he managed to instal a thermostatic shower back to front amongst other things)

[gucciman]

trv's are normally fitted onto the flow but if they're bi-directional then it doesn't matter.

if the rads aren't heating evenly then you could have a sludge problem, otherwise id be looking at a faulty pump not circulating the water properly.

[MrsMaria]

Thank you everyone for your answers, I think I'll leave well alone!

[johnk]

It shouldn't be difficult to turn the valves around if they are on the wrong way, just watch out for spillage
John