Radiator cold, then heats up when next one is turned off

[anthonyseoul1]

Hello,

I installed a new radiator in my kitchen. The kitchen has two radiators. The newly-installed radiator stays cold when the heating is on. However, as soon as I turn off the TRV on the other nearby radiator, it starts to heat up.

What might the problem be?

Thanks for your help

 

[ianmcd]

bet you have teed the new rad into the two pipes for the old rad ? what size of pipes are they and what size are the rads ?

 

[anthonyseoul1]

bet you have teed the new rad into the two pipes for the old rad ? what size of pipes are they and what size are the rads ?

The pipes are 15mm and the rads are 150cm and 170 cm singles.

I teed off the pipes to connect the new rad.

Do I need to balance the system?

 

[ianmcd]

wont do anyharn giving balancing a try