new boiler, rads are cold at bottom and 1 doesnt work

[angela1982]

Hello Angela

How old is the house?

As siad above Microbore is the size of pipework.

Bod[/quote]

Hi Bod, as you can probably gage i dont know a lot about this sort of thing! the house is 14 years old but the pipework and boiler is only 2 years old. i think its the 15mm pipework we have.

 

[angela1982]

That just means they are fully open, balancing is done with the lockshield valves. Worth checking with thermostatic valves though that the pin hasnt stuck in thus holding valve closed. Remove head and gently press pin, it should go down then spring back up when released. If its stuck down the valve is closed.

I think thats a bit out of my comfort! zone! i switched all rads off and the one which didnt work, filled up nicely. so i switched that back off and I am now working my way from the start of the system and switching each one on as soon as the previous one fully fills. just hope that works!

 

[angela1982]

Hi angela. Just going back to your opening post - has the extention been finished entirely now and what's happening with the plumber? Is he due to come back and finish it all off and try to balance it all?

Hi,
yes the extension has been finished for over a year now and it was all balanced and working, although there was always one radiator that was cooler than the rest, but never the same one, it would change each time!! We had a plumber who fitted the boiler and new pipework before the extension. When we had the extension done he was ****ing us around so we had to get another plumber in to do the new rads. He balanced everything and it was all working fine. last summer we had some decorators in and they took one rad off and its since then it hasn't worked properly. the new plumber has been back since to fit a new fireplace for us, and he tried to identify the issue whilst he was here, and came to the conclusion that it might be the overuse of bends in the back bedroom which makes the system not work properly. he said the old plumber didnt do a good job of the pipework! but how do i know if this is the issue!

 

[Agile]

I still dont see any reason why the rads would not work properly if properly balanced.

Balancing is mostly with the lockshields up to one turn open!

A good start is to open each one just 1/2 turn!

Tony

 

[Hugh Jaleak]

If all the rads will work individually then there's no major problem, its a balancing issue.

You need to throttle back the rads nearest to the boiler/pump to force the output around the furthest parts of the system. It can be done, just takes time! Close off the lockshields on the nearest rads, then open 1/2 turn at a time, if far rads start cooling close nearest rads lockshields 1/2 turn.

 

[angela1982]

well im currently working my way through switching each one on in order of near to far from the system, and letting air out where needed. On rad number 6 and they're all staying hot at the moment.

Thanks everyone for all your help, its really appreciated.

 

[angela1982]

If all the rads will work individually then there's no major problem, its a balancing issue.

You need to throttle back the rads nearest to the boiler/pump to force the output around the furthest parts of the system. It can be done, just takes time! Close off the lockshields on the nearest rads, then open 1/2 turn at a time, if far rads start cooling close nearest rads lockshields 1/2 turn.

right, so i'm onto rad number 7, and rad number 1 and 2 are cooling down at the bottom. I'm going to keep switching each one on, but based on this do you think it must be a balancing issue?

 

[Agile]

You dont need to let air out of anywhere at this stage.

How much are you opening the rad valves?

Tony

 

[Bodd]

I may be banging down the wrong ally hear.
But a 14 year old house may have a microbore system and if so this could be the problem. I take it that the boiler is new but the pipe work is old apart form to the new rads?

Bod

 

[angela1982]

Hi Bodd,

No then pipes and boiler are new, 2 years old, we have the 15mm pipework.

 

[angela1982]

You dont need to let air out of anywhere at this stage.

How much are you opening the rad valves?

Tony

The rad I let air out of was cold at the top but hot at the bottom. The first rad that I came across which didn't heat up fully I turned half a turn at a time. But the radiator that is next on the system after that didn't heat up at all, thermostat up to max, I took that off and checked the pin wasn't stuck but even turning the lockshield by half a turn at a time it didn't heat up, so that's when I amandoned it.

 

[Agile]

When balancing you dont make changes by 1/2 turn at a time!

About 1/8th of a turn around the 1/2 turn open is more usual.

I am not surprised that you have difficult turning it at 1/2 turn at a time.

Tony

 

[angela1982]

When balancing you dont make changes by 1/2 turn at a time!

About 1/8th of a turn around the 1/2 turn open is more usual.

I am not surprised that you have difficult turning it at 1/2 turn at a time.

Tony

Hi Tony, i dont know much about heating and I was following the advice of hugh above and that of other posts in the forum. When I turned them clockwise they turned for ages so must have been turned quite far open. How long shud I wait for it to heat up before doing anoter turn?

So should I switch off all rads at both valves, start with one closest to boiler and open up the therm to full and then turn the lockshield by 1/8 until it heats up fully and then move to the next?

 

[angela1982]

I still dont see any reason why the rads would not work properly if properly balanced.

Balancing is mostly with the lockshields up to one turn open!

A good start is to open each one just 1/2 turn!

Tony

Hi Tony,

Sorry i missed your earlier post. I've reviewed the link that Hugh has given me and I can see i need to have all lockshields open half a turn and then work my way around just moving them a little until they heat up.

The rads that were furthest away from the boiler had their lock shield open around 5/6 full turns.

p.s. should i start balancing the first rad and work forwards, or the last rad and work backwards?

 

[cantaloup63]

This is the link to the WIKI. It gives you an idea of what is involved to do it all "accurately" which requires proper equipment, but also an overview of the order in which to do them which is helpful at this stage.