Radiator Cold Goes Hot When Bled Then Cold Again

[m33ksy]

I think that is going to be my next option. Removing and draining. Also will make sure the radiator is not blocked. Should the flow be the same out of both sides?

 

[kevplumb]

yes

 

[m33ksy]

Many thanks i'll try it tomorrow and let you know how I get on.

Thanks everyone for your help so far

 

[rojaca]

Just to reiterate- re trv. If mono-directional or just knackered, if the flow is reversed going through the trv you won't get any circulation. the flow can shut the valve onto the seating.
However when you open only that valve and bleed through it it will give the appearance of the valve functioning correctly because the flow then coming in the correct direction
Most TRV's are bidirectional, but some have a collar etc which need adjusting if installed on return pipe

 

[m33ksy]

OK that kind of makes sense. So your saying even if I take the radiator off and try each valve they could both show good flow however the trv could still be knackered?

 

[m33ksy]

Hi it's now working fine. Took the radiator off to flush it and some blackish water came out but not really any sediment but realised water was only coming out one end. Turns out the side the trv is on the radiator had a plastic cap screwed in it no wonder no water was flowing! I guess the previous owners didn't want to use the radiator even though they could have just turned the trv off! Unless the radiator was installed with the cap on and has never worked for that reason as the house is only 2 1/2 years old.

Thanks all so much my spare room is now all nice and warm.

 

[seco services]

so how was you managing to bleed the rad when you shut each valve and bled rad ?

 

[awais]

undo the nut opposite side of the air vent for about half turn you will get some air out it worked for me several times i hope it should sort the problem out

 

[seco services]

undo the nut opposite side of the air vent for about half turn you will get some air out it worked for me several times i hope it should sort the problem out

are you paying attention it's already working.

 

[awais]

sorry chief

 

[seco services]

sorry chief