problem with one cold radiator

[rob7475]

Hi,

We have just had our central heating upgraded and I'm having problems with one radiator. initially, the radiator would get warm but not hot. now its stone cold.

i've tried bleeding it and water comes out. if i bleed some water out into a jug, the copper going into the lockshield gets hot. i've checked the trv at the other end and the pin moves freely.

i'm waiting for the plumber who installed to call me to arrange to sort it but its freezing in the bedrooom so would like to sort it before if i can.

boiler is a Worcester bosch greenstar 30si combi, pressure is at about 1.5.

cheers

rob

 

[John506]

Shut off all other rads by the TRVs, may be a blockage and this shuld shift it. If that fails and the rad goes cold again when you open all the other rads again, try opening the lockshield fully

 

[rob7475]

Hi,

i've shut off the trvs on all other rads that have them (i have a couple of skirting heaters that don't have trv's)

i've just tried bleeding the rad again and noticed that if i close the trv whilst bleeding, the lockshield side gets warm. If i close the lockshield, the side with the trv gets hot. not sure if thats useful or not??

Rob

 

[John506]

Because when you close off the TRV, and bleed, you are drawing water in from the return pipe which the lockshield is on.

You shouldn't really mess with the lockshield because you can unbalance the system.

What happened when you turned the TRVs to the hot rads off, did the cold one heat up?

 

[rob7475]

when i turn the trvs to the other rads off, the cold one stays cold. i'll try turning off the valves to the skirting heaters and see if it makes any difference.

Rob

 

[John506]

How many rads are cold?

Pins might be stuck down in the TRVs.

Do they even get a bit warm?

 

[rob7475]

just one cold rad - rest are ok. checked trv and pin moves up and down fine. rad and trv are only three week old and did get warm at the beginning.

Rob