John Rumm spake thus:

On 15/03/2012 01:34, Lieutenant Scott wrote:
Someone was telling me that it's important to connect the flow and
return to the right ends of a radiator. But I cannot see a problem in
water running the wrong way.

"The wrong way" would mean water flowing into the radiator through the
balance valve and out through the thermostatic valve, but the radiator
is symmetrical, and the valves are not one way (are they?), so what
would be the problem?

Some TRVs are one way. Some are described as two but work better on the
flow side, and some are fine either way.

Some are either way, but need to be adjusted for the correct direction -
this can be done after installation.