cold rads

[spoonse]

Hi there,
i have three lukewarm rads in the house-I've tried balancing them all from scratch but no luck so I took them off the wall and flushed them through with fresh water,still no good.I have an old microbore system and was wondering if it needs a proper flush through? The pipes are warm/hot below the valves but the rads somehow aren't getting warm-any ideas? thanks

 

[spoonse]

By the way there are no thermo valves on them

 

[JohnD]

close ALL the other rads.

do the cold ones now warm up?

obviously you have bled all the rads. Does water squirt out forecefully from all of them, especially the highest ones in the house?

 

[spoonse]

Yes mate I've tried closing the others down already but unfortunately the cold ones haven't changed at all .At present yes there is water there when bled on all of the remaining rads in the house

 

[JohnD]

then I would suspect a sludge blockage. It was important to verify first that water squirts out forcefully from the bleed screw on the highest rad in the house, or I would have suspected insufficient water.

However a chemical clean will not reach inside a totally blocked pipe as there is no flow to carry it there; and microbore with dual-entry valves are not very good at powerflushing.

Try taking the valve off the rad and see if both valve parts will squirt into a bucket. See if sludge or sediment comes out. If water squirts out of the bleed screw of the cold radiator, you know that water is able to pass down at least one of the pipes. While you have the rad disconnected, take it into the garden and squirt it through with the hose. Bang it on the back face with a rubber mallet or block of wood to help loosen sediment. Do not bang the front face as any scratches or dents will show.

If you can get any flow through the rad, you can use a chemical cleaner.

 

[spoonse]

thanks for that mate i'll try it out