One rad not hot

[OldBuoy]

Oldish system (maybe 40yrs) but reliable (one pump req in the last 14yrs)

All seems okay but one rad in a downstairs extension (a cold room at best) does not heat up very well. I took the rad off and flushed with a hose loads of manky water came out. Seems to have improved it a bit but still not as hot as the others.

Would a simple flush sort this out do you think? or should I call a heating engineer?

[OldBuoy]

I bled it the other day when i put the rad back on. I've shut off the other rads and running boiler full blast and the rad is now very hot. Does this point to a blockage or balance the system? I used to have (many yrs ago) some rad thermometers for this but can't find them anywhere now.

It could have been plumbed by a muppet, it's never been that good we've been 12yrs.

[OldBuoy]

Thanks, the dodgy rad has a thermostaic valve on the outlet side. This will make life fun. I need to check the other rads. IR thermometer on it's way from Amazon (£10)

Edited by OldBuoy on Thursday 9th October 13:14

[PositronicRay]

Well balanced them up, and all the rads seem better and the cool one is warming up.

One rad still gets bd hot, the lock shield valve is seized and I managed to shear the top of the spindle off trying to free it. So trying to regulate tht one by turning down the TRV.

Thanks for you're help and advice.

Edited by PositronicRay on Sunday 26th October 07:24

[PositronicRay]

g7jtk said:

TRV ion stuck. Remove head and tap pin repeatedly until it springs back and hot water flows. Wd40 and replace head. Job done.

TRV okay, it's the lockshield valve on the other end.