new radiator luke warm ?

[sophiesdad]

Hi all ,
firstly, what a great site , and the info i have learnt has already led me to tackle 2 problems succesfully , and although it took some, gave me some confidence.
well , now i have another problem and and hoping for some advise please.
i had single radiator in my dining room , but didnt heat the room enough , was told last year it was too small , so this year , i installed a double , got it plumbed in ok , but now cant get it to heat at all.
i have bled the system from cold , and balanced the rads, and all the others work fine , but not this. it was getting hot when it had the smaller one on there , but i am lost.
pump is ok , the flow pipe starts to get hot and then fades .
any ideas ? or shall get an expert in ?
thanks for anyones time to read and or reply, i will be very gratefull.

 

[villa_tom]

Is there a TRV on this rad? If so then its probably failed either the pin inside head its self, or the pin on the actual valve itself it could be stuck in the down position. If there is not a TRV then one of the rad valves could be at fault.

 

[shorticus]

You may also have created an air lock when you refilled, try shutting down the other rads (only needs to be by one valve) one by one to see if it gets hot then, when it does you'll probably have to vent it too

 

[sophiesdad]

Hi and many thanks for your replies.
it does have a trv valve but its brand new , as is the shut off valve the other end.
Will look at the air lock possibility tomorrow , will bleed again and balance again and get back.
thanks