2 new radiators are cold

[fowler1974]

Hi, can anyone help me please?

I’ve just added 2 radiators onto my system which are in a conservatory. The problem is they aren’t getting hot.

The boiler is: chaffoteaux et maury centora green 30 combi boiler. Originally there were 7 single panel rads on the system

So far I’ve tried:

• bleeding all the rads – successfully
• Balancing the rads - unsuccessful
• turned all the other rads off apart from these 2 for 3 hours – warmed up a little more but not hot
• sludge remover – unsuccessful

The only thing I haven’t touched is the boiler (as I’m not qualified) or the pump. The pump is a grundfos 15/50 pump without a speed selector (which I’ve looked for to try and increase the speed).

Has anyone got any ideas?

Thanks

 

[Bahco]

How have you piped them

Also look in here

 

[fowler1974]

what do you mean by piped?

One other point is the boiler is showing a problem with the 3 way valve being stuck in CH mode - would this cause a problem?

 

[Bahco]

what do you mean by piped?

How have you piped them up to feed them? Are they separate feeds, is it microbore etc?

The boiler is showing a problem with the 3 way valve being stuck in CH mode - would this cause a problem?

You won't get any hot water.

 

[fowler1974]

Thanks for your help.

They are T'eed from an existing radiator in 10mm plastic speed fit

 

[jackthom]

Did this involve a long run of 10mm to the new radiators and what size piping was feeding the existing radiator?

 

[fowler1974]

10mm was feeding the existing radiator (this rad never really got that hot either) and the new run was just the other side of a wall approx 2m then another 2-3m to the next rad

 

[Bahco]

Get rid of the 10 mm and do it properly.

Did you read the link I gave you

 

[fowler1974]

I did read your link, its very informative, thanks.

I was hoping it wouldn't be the pipework, is this definitely the prob or could it be anything else?

 

[jackthom]

There wasn't really enough flow to heat the existing radiator so there's no hope of getting enough through the new ones.

Can you trace the old 10mm pipework back from the existing radiator to where it joins larger bore pipes? You'll probably need to replace that old 10mm run with 15mm.

 

[fowler1974]

The TRV's got red hot - does this mean there's not enough ooomph to get it through the rads??

 

[jackthom]

It means the hot water is trickling through but there just isn't enough of it.

That could be largely due to the old 10mm being partially "sludged up" but even with new clean pipes you would still be pushing your luck using a long run of 10mm for three radiators.

 

[screech]

the pipework run was designed for just one radiator, adding 2 more on to it won't work, you need to trace the pipes further back. although i can't understand the logic of running 2 extra rads off of pipework that wouldn't even heat one?!?!?

 

[Steve69the69Gas]

Fowler,

Your last post says TRV red hot.

If so, take TRV head off and make sure the infamous pin is up and comes back up if you press it dowm.
Make sure the LS valve is open also.