DIY Doctor UK DIY Forums

I have recently drained the system to replace all radiators, how can. I tell which is going to be the feed and return pipes now I can turn the combi boiler on

Does the pump have an arrow on it showing directional flow? If not, a bi-directional valve should do the trick. Alternatively, whichever one heats up first is the feed!

Hi

Original post should have said the boiler cannot be turned on as the is no pipes attached etc so cannot feel which pipe gets hot first.
I believe the valves are multi directional these days so hopefully it won't matter when I re attach pies etc

It doesn’t matter which is the Heating Flow and Heating return at a radiator as the water will flow through the radiator anyway it can.