Cold radiators

[dave maden]

Central heating system been in nearly 3 years .now all of a sudden a couple of radiators aren't warming up .Have bled them and it gets hot immediately after the trv but rad not getting hot .I don't think it's sludge as rads only been on 3 years .What else could it be ? Thanks

 

[joni os]

Remove heads of TRV and press pin to make sure it moves freely. Pins stick if not used during summer months, sometimes a knock on side of valve is necessary to jar plunger free. Support opposite side of valve whilst knocking.

 

[dave maden]

Pins are ok they push in and spring out and it's hot just after trv .thanks

 

[joni os]

If not TRV then close TRV and uncouple from rad sufficient for water to escape this should clear any sludge. If your system is unvented reduce pressure first. Open and close balance valve at other end of rad. and leave fully open.

 

[Riley]

Other thing to try is close off other rads and see if you can force heat to the ones playing up

 

[JCplumb]

Is there a pattern to the cold rads, i.e. are they all downstairs, or all in one section of the house?