Fixing & optimising my heating system (oil + log boilers).

[Mysterae_]

Looks like heat is coming from the lockshield i.e. the return side and not the flow side.

Yup!

Ah! In reality, it shouldn't make a difference. It might even be better in the respect that the thermostatic head on the TRV won't be affected by the temperature of the TRV itself.

Some of the comments made me reconsider my thoughts on the lockshield and TRV being input and output respectively being the wrong configuration so after a bit of research...

Ultimately, if the radiator is working fine, then it's fine. Most modern TRVs are bi-directional so can work either way, but some can't and will "chatter" or just not work. Take the dynamic TRVs that I'm keen to install, they must be installed in flow side of the radiator to operate. Also if you don't know the valves are mixed up then balancing the system could be a challenge. It's best practice to put them on the right input/output put sometimes the desired location of the TRV (for ideal room temp detection) can trump it.
Something I didn't know is that some radiators aren't bi-directional and have the flow marked on them, particularly designer rads.

Interestingly as well, in Denmark they always put the thermostatic head horizontally so it's away from the radiator. They also put them top/bottom for better heat distribution (not sure which goes where).

Horizontally seems to be the most recommended way of fitting them but the least aesthetically pleasing. In Germany and some other European countries the flow in to the radiator is almost always the top of the radiator as it's more efficient, don't know why we don't like it in this country!

 

[dirtychinchilla]

There's lots of things wrong with heating in this country. We're so behind it's ridiculous. If PITRVs were installed in every house in the UK, we'd resolve a huge number of the problems we have, be more comfortable, and the pay back period would be very quick with the price of energy as it is.

I'm going for the vertical valves where they might get in the way of furniture. If there's no possibility of furniture getting in the way, I'll probably put the horizontal valves. Where we have the sort of bypass radiator, where the wall mounted themostats are (got two), I'll be using a fixed head instead of the thermostatic one.