New Radiator

[r1chm]

Hello

Just after some advice please. We have a 7ish year old combi boiler system in our house. Just had a new extension built and bought a 2400mm double radiator to go in there.

From what I could see when the ceiling in the kitchen was down, there are two 22mm copper loops (one flow one return presumably?) in between the joists, and each radiator in the house has a 15mm flow/return feed from these loops.

The plumber that originally put in the pipework in the new extension ready for the new radiator (they didn't supply radiator I bought it separately) used 10mm barrier pipe off of an existing 15mm copper feed from an existing radiator. He said it'd be fine and left it at that. I thought at the time that if it was me doing it (DIY-style) id have personally followed the model and gone from the 22mm "ring" and used 15mm barrier pipe not 10mm, but I'm not a plumber so didn't really kick up a fuss.

Fast forward a couple of weeks and I purchase the 2400mm long radiator as mentioned above, hang it on the wall and connect it to the pipework, fill it up, release trapped air, put more pressure in boiler, release last of air, check boiler pressure and then turn the heating on.

After a good half an hour i touched the radiator and only the top half of it was hot/warm, the bottom half was mildy warm at best. No trapped air came out of the bleed valve, just a constant stream of water. The 10mm flow pipe to the radiator was hot and the 10mm return pipe was, well i couldn't feel any heat in it whatsoever.

I presumed therefore it was a flow issue. I checked to make sure both radiator vales were wide open, they were. So, assuming it was a problem with the piping I decided to swap it around (after some inventive language about how I should have said something to the original plumber...).

I ripped out all of the 10mm barrier piping and re-ran 15mm barrier pipe directly from the 22mm copper loops mentioned earlier all the way to the new radiator. Connected it to the radiator, released trapped air etc, increased boiler pressure and turned heating on, aaaaaaand I have the same problem.

The flow pipe is hot to touch but the return just has no heat in it, so the water is not being cycled through the radiator. Both valves are wide open. Every other radiator in the house acts as it should do. I even turned off all the other radiators in the house and it didn't seem to affect the new radiator at all.

I'm a bit stuck now, i felt sure it was the small diameter piping at fault but I guess not.

Does anyone have any ideas? I have an old 1m radiator in the shed which I might connect up at the weekend to rule out a faulty radiator but i guess a faulty radiator would be pretty rare?

Is the new radiator just too big?

 

[PlumbBobBob]

it sounds like a balancing issue to me close down all the rads that are working and see if the new one works. if it does then slowly open the other rads one at a time until they are all coming on.

 

[SimonG]

Waters lazy, it will take the easiest route. How many radiators do you have?

 

[r1chm]

Hi, 8 Radiators in total.

I turned the others off completely and it didnt seem to change?

Thanks for the replies

 

[Matt06]

He said he shut all other rads and nothing changed

Take a picture of rad valves if they are not standard lockshield / wheel head ones I.e some towel rail valves have a non rising head so you might think it is fully open but it is actually stuck / Mis alligned in the valve if that makes sense .

how long are you waiting to feel temp of return pipe? probably take a while to come hot as 2.4m rad double panel ?

I would have ran in copper bigger internal bore and i feel plastic is for non plumbers tbh though i don't think that is your issue just saying unless the plastic pipework sags causing the top half or parts of the pipe to have air in rather than filled with water

 

[r1chm]

Hi, 8 Radiators in total.

I turned the others off completely and it didnt seem to change?

There is no sag in the plastic piping from what i can tell, it runs horizontally thro the ceiling joists, then a drop from ceiling to skirting board height and then horizontally again until it gets to the radiator valves.

These are the valves im using directheatingsupplies.co.uk/bulldog-trv-and-lockshield-valve-pack-15mm-643100?gclid=CLSi7aLj7sMCFSXItAodMS8A3w

The plastic pipe on the flow side is really hot up to the valve, and then the rad is only hot at the top, feeling it after 30 mins or so. Bottom of rad not warm and the return pipes not warm either.

Would a higher boiler pressure be better? I think its currently set at about 1.25bar

Thanks
Richard

 

[tom609]

are you sure the 2 pipes are flow and return or it could be a 1 pipe system and by-passing the radiator

 

[r1chm]

Hi Tom609.

Fairly sure?

I had the benefit recently of the kitchen ceiling being removed. I could see three radiator feeds from the kitchen.

Each radiator had 1 feed from 1 of the 22mm copper rings and another feed from the other 22mm copper ring.

 

[tom609]

Take the radiator off and link the two valves see if it flows through it is possible for it to be the radiator, what is the pump setting, although you would have thought if you had all the other rads shut down it would have worked is thete a manual by pass on the system that is fully open

 

[r1chm]

Take the radiator off and link the two valves see if it flows through it is possible for it to be the radiator, what is the pump setting, although you would have thought if you had all the other rads shut down it would have worked is thete a manual by pass on the system that is fully open

Ill try this tonight. Thanks for the idea. I don't know what the pump setting is or how to check it... ?

 

[r1chm]

Ive just read this advice on the Internet...

Turn off both valves drain rad off take rad off, put a bowl under valve on one side to catch water open valve and let water run when it gets hot turn off valve and repeat at other valve put rad back on and refill rad by filling half of rad from one valve and turn off and other half from other valve then make sure you open all valves when finished

Can someone elaborate on this? Its the valves bit Id like some clarity on. Do I turn off ALL radiator valves before trying this method or do I just turn off the radiator i am working on at both ends? Has anyone tried this method? I cant see how its any different to bleeding the radiator but im willing to give anything a go!

Thanks

 

[r1chm]

...just an after thought... does it matter what side you put the thermostatic valve and lockshield? Im wondering if ive got that the wrong way round?

Currently the thermostatic valve is at the Flow side and lockshield at the return side

 

[Simon F]

that only matters if the trv is one directional.

 

[hammers4spanner]

Plastic is for non plumbers??
every new build in this country has been installed by non plumbers then

 

[PriestyUK]

I think you have a balancing issue, the rad's before your new rad are getting a easy ride, throttle those ones down slightly to encourage the heat to push past them ones and get to your new rad.

 

[tom609]

I think you have a balancing issue, the rad's before your new rad are getting a easy ride, throttle those ones down slightly to encourage the heat to push past them ones and get to your new rad.

He has previously stated that he has turned all other radiators off with no significant improvement as for the trv I personally prefer them on the return have you checked for a by pass

 

[jonnyswamp]

Remove the rad and make sure you get a good flow through both valves making sure all air is removed (may need to have someone at boiler topping up pressure), if so, then check for any blockage in the rad/rad tails (put a hose on one end and see what flow is like out the other)
If all above are good then theres no reason why it wont work when all other rads are off

How big is the extension to need a 2400mm double?

 

[r1chm]

Hi just an update on this.

I actually do anything further with this radiator, one day when the heating was on it went from just luke warm as described in my original post to roasting hot all the way through until about 1 inch from the bottom, which is still hot but still not as hot as the top of the rad is.

The return pipe is still also not as hot as the flow pipe, but is noticably hotter than it was when I made my original post. It has acted this way ever since.

So i wonder whether it was just more trapped air which has made its way around the system as I did have to bleed the upstairs towel rail after we'd noticed the new rad was heating up more or less as it should do.

Maybe with a little more running any remaining air will also be pushed through and the bottom 1 inch of the rad will also heat up properly, but i am not to concerned about it to be honest!!

Thanks for all your help.

 

[Matt06]

Plastic is for non plumbers??
every new build in this country has been installed by non plumbers then

Sorry that was a stupid comment, Just most of the installs i see with plastic i would hope were not done by a plumber. Plastic curling round the lofts / airing cupboards instead of cutting and clipping neatly

 

[plumben]

Sorry that was a stupid comment, Just most of the installs i see with plastic i would hope were not done by a plumber. Plastic curling round the lofts / airing cupboards instead of cutting and clipping neatly

plumbers with no pride in there work more like it