cold rads downstairs

[Chivas69]

Hi
Have a small 3 bed house with 7 rads in total, 4 upstairs and 3 downstairs! They and the boiler were fitted brand new 7 years ago and we have a combi boiler fitted in a cupboard upstairs! After some exploring I have found out that they are fitted from a manifold under the floorboards on the landing! (Microbore?)
All rads have got hot in the past but recently I noticed the hall and front room rads were not getting that hot! They were also warmer at the top which I though was possibly sludge so I took off the cooler rad (hall) and gave it a good hosing outside! No sludge came out and the water was virtually clear!
All roads have been fully bled and I've balanced them!
I got system back up and running but no joy!
I then tried turning all upstairs rads off at both ends to see if this would heat the lower rads and they did get a little warmer but not much!
Also we have a rad in the kitchen and this gets very hot!

System pressure is fine
I thought maybe blocked return pipes from rads so I locked windshield and gently undone the pipe to the rad and clear water was running out which got hot as it was fed from manifold! Still no joy so I bled again and 're pressured system!
I then thought pump was playing up but it seemed to be working ok and if it was pump how come the kitchen rad was ok!
Never the less I undone the chrome slot in pump and water trickled out and with a 3mm screwdriver I tested for movement and it was fine! It also sounded fine and flicked through the 3 settings with ease, speeding up and slowing down!
Now the system has all worked for 7 years BUT I've read that using microbore the pipe to each radiator should be no more than 5 metres from the manifolds yet for the two coldest rads it's probably more like 8 metres! Could this be the problem? Could the pump be struggling after these years!
The piping is 22mm to the manifolds and then pushing type fittings of 10mm to each rad and back!
My next step I think is a system drain or maybe some sludge cleaner?
Any help is gratefully received!
Thanks

 

[jackthom]

You don't mention any TRVs, so just to be sure have you taken off the heads and checked that the pins haven't seized either fully or partially closed?

 

[Chivas69]

Hi mate, the rad in hall is the control so no trv, one in front has trv and checked and pin is fine!
All upstairs have trvs but I haven't checked them as the rads are red hot! Should I check them incase?
Cheers for any help!

 

[jackthom]

No don't worry about the TRVs on the radiators that are already hot.

Is the pump now on setting 3 ?

 

[Chivas69]

Yes but as far as I know it's been on setting 3 since they fitted it 7 years ago! I've never touched it anyway!

 

[D_Hailsham]

I have found out that they are fitted from a manifold under the floorboards on the landing! (Microbore?)

If the pipes to the rads are 8 or 10mm, then it's microbore.

Only one manifold for the seven rads?

All roads have been fully bled and I've balanced them!

How did you do the balancing?
How long ago?
How far open are the lockshield valves?

Also we have a rad in the kitchen and this gets very hot!

What happens if you turn this rad off?

 

[Chivas69]

I have found out that they are fitted from a manifold under the floorboards on the landing! (Microbore?)

If the pipes to the rads are 8 or 10mm, then it's microbore.

Only one manifold for the seven rads? It's. A 3 and a 4 linked together!

All roads have been fully bled and I've balanced them!

How did you do the balancing? The 12 degree thing! Plus all worked fine before and still no heat in the two rads when all other rads are locked off!
How long ago? Yesterday!
How far open are the lockshield valves? Not much on the uppers, almost all the way on the lowers!

Also we have a rad in the kitchen and this gets very hot!

What happens if you turn this rad off?

nothing, other rads still cold!
Cheers

 

[D_Hailsham]

It's a 3 and a 4 linked together!

Hopefully the 3 does downstairs and the 4 upstairs.

The 12 degree thing! Plus all worked fine before and still no heat in the two rads when all other rads are locked off!

Beginning to sound like a blockage. How did you measure the temperature?

Not much on the uppers, almost all the way on the lowers.

LS valves should be no more than about 1 turn open. Usually half a turn or less

Also we have a rad in the kitchen and this gets very hot!

Does this rad come off the manifold?

 

[Chivas69]

It's a 3 and a 4 linked together!

Hopefully the 3 does downstairs and the 4 upstairs.
Unfortunately not, they seem mixed in and they come from the same 22mm pipe!

The 12 degree thing! Plus all worked fine before and still no heat in the two rads when all other rads are locked off!

Beginning to sound like a blockage. How did you measure the temperature? With temp gage on each rad pipe, flow and return

Not much on the uppers, almost all the way on the lowers.

LS valves should be no more than about 1 turn open. Usually half a turn or less. That sounds about right for upstairs but I'm guessing when it was fitted they didn't spend much time balancing, or they had to open downstairs much more than up!

Also we have a rad in the kitchen and this gets very hot!

Does this rad come off the manifold?

Yes mate (I'll try and upload a pic in next post!

Thanks for the help!

 

[Chivas69]

 

[Chivas69]

 

[D_Hailsham]

Untitled

• Chivas69
• 14 Dec 2014
• 1

That looks like 8 rads to me???

 

[Chivas69]

The one on the farthest right is just a link between the manifolds, think its a safety feature incase all rads are shut off!

 

[D_Hailsham]

The one on the farthest right is just a link between the manifolds, think its a safety feature in case all rads are shut off!

I did notice that after writing my last post. That could explain why the link has a kink in it - acts as a crude bypass valve!!

Which boiler do you have (make and full model no)?

 

[Chivas69]

Ferroli optimax HE 31c