I have several reclaimed cast iron radiators which I'm installing. The internal thread of the connectors appears to be 1.25" so will require reducing bushes. I'll be using standard 15mm TRVs, etc. so assumed I'd need 1.25" to 1/2" reducers but looking at the valves the external thread seems to be 3/4". So are 1.25" to 3/4" reducers the correct size for standard TRVs?
Thanks.
Thanks.