Radiator air locked?

[LeeST]

Hello,

I have had a small extension built with a vertical radiator installed. Only 3 out of the 5 panels get hot. The 3 to the left. The 4th gets slightly warm the 5th almost nothing

My system is gravity fed and 10mm microbore feeding each radiator

It was drained to fit the radiator and has always been terrible for bleeding it and getting the air out.

Based on the above I assumed it had air in it, even though no air comes out the bleed valve. The towel radiator in the en suite I bleed every day and always get some air out, assume it all ventures here as it’s the highest point in the system.

I tried something I read on here about forcing it by turning some other roads off, basically if I turn nearly everyone off (say 10 out of the 12) I can force all 5 panels to get hot and it stays hot even when I put the others back on.

From cold however it’s back the beginning. Only 3 panels get hot.

I’m going to ring the plumber perhaps tomorrow but before I’m blinded with science, what does the problem sound like to you? All other radiators get steaming hot and I guess the pump is up to it, it’s quite new and has different settings but none help, slow/fast etc

I think system is well balanced. I’ve checked them all and adjusted the lock shields and left the new rad fully open. They all warm up together but this one isn’t having it.

If I turn most of them off then turn the kitchen one (another vertical) from on to off and back again I can hear water trickling in it so clearly still has air in. But even the ones with air still get very hot

Thanks in advance

 

[Newboy]

First step would be to balance the radiators

https://www.diydata.com/projects/centralheating/balancing/radiator_balancing.php

 

[terryplumb]

Probably a Balancing problem .

 

[LeeST]

Would an infra red thermometer gun thing work ok? I have one of these and seems reliable?

Or do I need something proper

 

[terryplumb]

I suppose it depends on how accurately it can be focused onto the pipe. Try it and see.

 

[CBW]

I could be way off here, but what size (kw) boiler do you have? It could be a balancing issue, but you may need to check/have checked the boiler can provide the demand.

 

[LeeST]

I believe boiler should be ok. I checked he output and then went round and sized every rad up. Can’t remember exact results but seemed a lot spare

Once I start balancing do I have to wait for the first rad to get up temp to check for the 12 degrees difference or do it as it’s warming up?

 

[dilalio]

My first thought... Vertical (designer) rad... is it a directional one, that stipulates which side should be connected to flow and which to return?

Many do, as they have a baffle/deflector inside!

 

[LeeST]

My first thought... Vertical (designer) rad... is it a directional one, that stipulates which side should be connected to flow and which to return?

Many do, as they have a baffle/deflector inside!

Interesting point.

I have no idea, never saw the box opened but the guide online doesn’t mention anything.

It’s a Milano Skye with a central h block valve underneath

 

[dilalio]

Hmmnn... Guide isn't very specific is it!
Then again, maybe only mentioned if it was important... Strange things MI's

Maybe a call to their technical will give some guidance, otherwise I'd get with the balancing.

 

[LeeST]

Going to start the balancing today. See what happens. Then speak to the plumber

 

[LeeST]

Might also be worth mentioning. To get a 1900w radiator in the gap I wanted it to go in, there wasn’t much choice so ended up with an aluminium one.

The spec on this says volume is 2.28 litres as opposed to the steel ones which were more like 18 litres.

It was driven more by design than functionality which I know is the wrong was round but I did think that less water would be better and heat up quicker. Although as it’s aluminium with hardly any water in cool down faster also.

 

[LeeST]

Thanks guys

Balancing worked. I always thought they must already be balanced as the lockshields were all at different positions

Also turns out I have 2 downstairs radiators where the lockshield valves are on the flow rather than return. So probably wasn’t helping much

All sorted now I believe

 

[snb]

lockshields can be on either flow or return. They are bi directional these days. We normally set the rads with lockshield valves open 1 to 1.5 turns open as a starting point and then adjust afterwards