One Radiator Cold. All others are off, and system is newish?

[Wiggy1983]

Hi, I know this is a common question, but I have searched a fair bit without much joy. So some help would be great please.

I have one Radiator that at best gets just medium warm at the top half. All the others work fine. I thought balancing may be the answer, so I've shut all the LSV's on the other Rads and obviously made sure it's open on the Rad in question. Now I'm getting absolutely nowt in the way of heat.

I've made sure the RTV pin is free, and I've bled the radiators round the house quite extensively (although I can't seem to get all the air out). The whole place is only 3 years old, so it can't be sludge??

I hope my little diagram answers the Q's on my setup.

Oh the problem radiator is No.5.

Untitled

• Wiggy1983
• 12 Jan 2010
• 1

 

[electronicsuk]

I notice the TRV is fitted on the return - is it a type that allows flow in either direction? As the installation is relatively new I would assume it is, but worth checking.

 

[Wiggy1983]

Thanks for the reply.

I checked on the makers website and they are bi-directional.

 

[Wiggy1983]

Maybe it is an air lock. It's weird, I've turned the LSV's back on, then bled LOADS of air from most of the rads - then I get good heat on all radiators.

Problem solved you may think, but I did the same procedure a few weeks back when troubleshooting the same problem. The heat comes back great for a while, then fades again slowly.

Where could the air be coming from??

 

[electronicsuk]

Where could the air be coming from??

Depends on the type of system. If it's vented with a F+E tank then pumping over through the vent pipe could introduce a lot of air into the system, as could poor placement of pump. If it's a pressurised system than the use of non-barrier plastic pipe can also allow air into the heating circuit, although perhaps not at such a rate as you describe.

 

[Nige F]

" 3 year old "+ "microbore" = Sorry but it`s the most likely reason . Any chance of pursuing the ( national? ) housebuilder.

 

[Bahco]

Your answer will be in no 2 here

Microbore = poor flow and longer to heat up.

 

[Wiggy1983]

Thanks very much for the replies guys. Sorry for lack of response for a while.

I don't find the Microbore to be a problem. With the Boilermate the Rads get hot very quickly.

After more playing round with the system I've found something quite bizarre.

Rad 5 will only get hot if Rad 4 is on.

Rad 1 will only get hot if Rad 2 is on.

Rad 3 gets hot independently of all the others.

So for example, if I turn off all the Rads in the house except 5, it won't get hot until I turn on 4.

Surely 5 and 4, and 1 and 2 aren't in series?!? I've been in the loft but can't get to the manifold to have a look.

I just can't fathom it. Please, anything to enlighten me would be great.

 

[Wiggy1983]

Where could the air be coming from??

Depends on the type of system. If it's vented with a F+E tank then pumping over through the vent pipe could introduce a lot of air into the system, as could poor placement of pump. If it's a pressurised system than the use of non-barrier plastic pipe can also allow air into the heating circuit, although perhaps not at such a rate as you describe.

As for if it's a vented or sealed system, that's something else that's confusing me. My system appears to possess both......

I have a F+E tank on top of the Boilermate, with a ball cock in it. I understand this keeps the CH system topped up. Correct me if I'm wrong.

Next to it I have a PV with a gauge on the side, and a braided hose to the cold supply. The gauge never reads anything above 0 from what I've seen.

According to the manual of the Boilermate this was an optional extra, but it doesn't explain (and I have no idea) what it's for.

Sorry for the questionathon guys. Thanks for any help.

 

[JLMGas]

Take a look here >> http://www.gasapplianceguide.co.uk/Boilermate BP.htm

See if there is an expansion pipe over the F&E tank

It may be that you have a pressuzized system and you need to pressurize it, with the braded hose!

 

[Wiggy1983]

After a few years of putting up with this problem I FINALLY decided to get my bum into gear and investigate properly. I'm between jobs, so I had no more excuses! Also I use read this forum frequently, so thought I owe an explanation to anyone else who may have this problem.

Upon peeling back the insulation, I was greeted with..........

IMAG0218

• Wiggy1983
• 7 Dec 2016

The bottom 90° bend is the Flow to Radiator 4 (see diagram up top).
The top 90° band is the Return from Radiator 4, and the Flow to Radiator 5!
The middle 90° is the Return from Radiator 5 (and 4, I suppose).

So in a nutshell, the installers fitted them in series! No wonder the heat from Rad 5 was so weedy, and took ages to warm up!

After a quick visit to Screwfix........

IMAG0219

• Wiggy1983
• 7 Dec 2016

Does anyone have any idea why they would have done this!? They've only saved themselves a couple of Tee Pieces, and as you can see, no saving in pipe routing.