Newb - please bear with me - I use this a lot for reference and advice, but first question. I have one radiator that refuses to get anything more than luke warm. I just spent most of my Sunday replacing it with a new one and new TRV and lockshield - with only marginal difference.
Let me try and explain....
The boiler is in the roofspace. There are 12 radiators in the house, on 2 floors. The problem one is in the living room (ground floor) which is an extension. The flow and return are buried. I cant work out the order of the rads, but it isnt the most physically distant from the boiler, but it is the only one to have buried pipes - the other downstairs rads are all fed with pipes that come down from the ceiling,
It is the last to get heat, the flow pipe gets hot. and after a while, the radiator gets warm at the top, then lukewarm all over. I assume this is just conduction from the flow pipe, rather than water movement. The return pipe stays resolutely cold.
There is a drain valve on the return pipe. and if I open that (after closing the lockshield) , within a few seconds piping hot water will flow out of it. So return is not blocked, and no sign of an airlock
Its slightly better after changing the rad today, but not good. If I turn all the other rads off in the house, it gets almost hot, but not too hot to touch. The other rads will get hotter when they are on.
I dont know where to look next - changed all components, no blockage, no airlock. Im guessing that it could be bad layout of pipes due to the long spur and the return flow is inhibited somewhere, or possibly the pump doesnt provide enough force to lift the return water from under the ground to the roofspace. I dont know - strictly amateur.
Any thoughts or suggestions gratefully received.
Let me try and explain....
The boiler is in the roofspace. There are 12 radiators in the house, on 2 floors. The problem one is in the living room (ground floor) which is an extension. The flow and return are buried. I cant work out the order of the rads, but it isnt the most physically distant from the boiler, but it is the only one to have buried pipes - the other downstairs rads are all fed with pipes that come down from the ceiling,
It is the last to get heat, the flow pipe gets hot. and after a while, the radiator gets warm at the top, then lukewarm all over. I assume this is just conduction from the flow pipe, rather than water movement. The return pipe stays resolutely cold.
There is a drain valve on the return pipe. and if I open that (after closing the lockshield) , within a few seconds piping hot water will flow out of it. So return is not blocked, and no sign of an airlock
Its slightly better after changing the rad today, but not good. If I turn all the other rads off in the house, it gets almost hot, but not too hot to touch. The other rads will get hotter when they are on.
I dont know where to look next - changed all components, no blockage, no airlock. Im guessing that it could be bad layout of pipes due to the long spur and the return flow is inhibited somewhere, or possibly the pump doesnt provide enough force to lift the return water from under the ground to the roofspace. I dont know - strictly amateur.
Any thoughts or suggestions gratefully received.