1 warm radiator upstairs when heating turned off?

Question

I have got 1 warm radiator upstairs when the heating system is turned off and the hot water is on. Is this a problem with a check valve and if so where would i find it?. Have done some repairs in the past so not a complete novice but unsure regarding this one. any help appreciated

Answer 1

That's normal in some systems, this is called an expansion rad , the hot water tank gets hot and can not store any more hot water,  just like a kettle when it boils lets off steam, and this is the process only  instead of letting off steam it goes into another rad.