New Radiator Got Hot Now Cold -Why ?

[Gary500]

My CH system is circa 20 years old. My hot water was fine, my four rads upstairs were piping hot, my hallway rad downstairs was also piping hot but the two rads in my lounge were cold so I took off the largest cold rad and flushed it through. When I put it back, opened the valves (I have no trvs) and let the air out it got hot straightaway but then went cold. All the other hot rads remained hot. As I thought the rad was terminal I bought a shiny new one but when I connected it up, opened the valves and let the air out, it too got hot immediately and then went cold. As before all the other hot rads stayed hot. The supply pipe is hot but the return is cold. The rad is actually stone cold at the bottom but very very slightly warmer (but still cold) at the top. Can anyone explain why a rad should fill with hot water and then go cold? It can't be blocked, it's brand new! The pump is only 12 months old and has no trouble moving hot water around to the other rads. It has recently started making gurgling noises whereas before, it used to run so quiet I had a hard job to tell if if was going. What remedial course of action should I take to get my cold rads hot once more?

 

[doitall]

Blockage in one of the pipes, try filling the rad with one valve turned off, or better still take the rad off and connect a hose pipe to each of the tails in turn.

 

[Gary500]

After connecting up the rad I only opened the valve on the supply side, then bled it and then opened the lockshield valve. This is a brand new rad, it can't be blocked already surely ? What are the chances of the return pipe being blocked somewhere ? I'm going to shut off all the working rads and see what happens.

 

[gavinda]

read the post above you. or perhaps get someone that knows what they are doing in... may save you some omney. i always get this wheni quote for powerflsuh..

its only 2 rads not working, ill just buy 2 cheap rads.


sure thing guy..see you next week