Cold radiator

Luckysasha

Can anyone help me out please. We got a brand new heating system fitted 5 years ago. Total refurb new pipe work etc. last year and again this year the rad in one of the rooms is heating on top and cool on the bottom. I have read similar threads where people suggest its a build up of sludge in that rad but honestly can sludge build up that quick.? All the rads are fitted with Trv's so I swapped the one on this rad with another one to prove the Trv's wasn't stuck. Another problem I have is one of the other rads needs to be bled at least once a month. Could the two problems be connected?

Dtp1979

Luckysasha wrote: »

Can anyone help me out please. We got a brand new heating system fitted 5 years ago. Total refurb new pipe work etc. last year and again this year the rad in one of the rooms is heating on top and cool on the bottom. I have read similar threads where people suggest its a build up of sludge in that rad but honestly can sludge build up that quick.? All the rads are fitted with Trv's so I swapped the one on this rad with another one to prove the Trv's wasn't stuck. Another problem I have is one of the other rads needs to be bled at least once a month. Could the two problems be connected?

Yes it's probably connected. If you turn off all rads except the bad one, does it heat up completely? And yes sludge can build up after 5 years easily if there's a problem with the system. The fact you're bleeding the rad so often suggests you have a problem

Luckysasha

Thanks for the reply. You suggest a problem because of having to bleed another rad. Any idea what this problem could be? Surely if air was getting in then water would be getting out no ? I will turn off all the other rads and see what happens

Dtp1979

Luckysasha wrote: »

Thanks for the reply. You suggest a problem because of having to bleed another rad. Any idea what this problem could be? Surely if air was getting in then water would be getting out no ? I will turn off all the other rads and see what happens

Yes water could be escaping out. If under a concrete floor then you'd never see it.

dersawazzie

Could be a simple balancing issue, although as the other poster said cold spots and constant bleeding tends to signify sludge. Does the affected radiators cold spot appear as an arc or half moon in the radiator ?

Luckysasha

No it's a straight line about a third of the way up from the bottom that's cold. I tried closing the return side half way to see if this would help but it stayed the same. This particular rad was moved about 18 months ago. Could it be something as simple as a bit of dirt stuck somewhere ? Both the flow ad return pipes where extended about five feet

dersawazzie

I'm assuming the edge/sides of the radiator is hot, the water has to get in/out somehow (I may not have explained myself!). So sides and top are hot as 'normal' , centre low down is cold ? Sounds like sludge alright, if there was a restriction to or from the radiator, it would affect any heat to it so it would tend to be poor even where it heats. Do you have TRV's ?

Luckysasha

Yes all rads are fitted with Trv's but I swapped the one on the problem rad with a good rad to prove it wasn't the valve. What's the procedure for getting rid of sludge. Can I isolate the bad radiator and just flush it outside in the garden or would you advise flushing the whole system ?

Billy Bunting

Luckysasha wrote: »

I will turn off all the other rads and see what happens

Did you do this ?

dersawazzie

Honestly without inspecting a system it is impossible to see if sludge is present. Flushing a radiator on it's own is a quick but effective way of solving an individual radiators problem, but as you said earlier you are bleeding the system regularly and whilst one radiator a month is not excessive, combined with cold spots it may indicate a good flush is in order, with correct system cleanser and inhibitor.

Is it an open system or pressurized ?

When you say you changed/swapped the TRV's was it just the head or the body as well ?

Getting a proper diagnosis and possibly powerflushing the sytem is costly. Flushing a radiator is (if sludged) a cheaper way to go, and was a way we used to clean systems years ago before powerflush machines were available, but may not solve the long term problem.

I've probably been no help at all because it really is down to your own circumstances.