Recent content by Tomas

Doubt that the join in that position is doing any harm. A few factors determine the max lenght, have a look here Should answer a few questions :shock:

Would the addition of thw two new radiators cause one of the original two to stop working altogther? Could do. I would expect it to get some heat though after a bit of time. It is possible that the existing rad that's not heating may have air lock and is unrelated to the new pipework going...

Check for the blockage first, but I think asking 15mm to supply heat to 4 rads may be at bit much in this configuration. I visited a job last week, The owner of the house had added two new rad to the system that would'nt heat up. Everything pointed to a blockage (if he closed all the rads...

If I follow correct, You have 15mm comming from the main 22mm circuit upstairs. This may have to be upped to 22mm, With the new 22mm in an upside down T to the down stairs rads. Carry the 22mm as close to the wall on the diagram and as far as you can on the left hand rad, Tee in the new rads and...

What Pipe size are the flow & return from upstairs? And the size to the radiators(flow & return?

Try opening the battery holder on your stat. Keep it open until the temp reading fades away and is no loger visible(up to 10 mins to fade). Put the holder back in to the stat and pop the temp up so the boiler flame appears on the stat. That should reset the unit .

Are the pipes to the upstairs radiator that U tee'd off also 10mm microbore? If they are then they may not be able to supply enough heat to both radiators. Try turning off the bedroom radiator to see if the new rad heats up any better.