Towel Rail strange happenings...

[Gavin Rafferty]

Hi all, I am new here and looking for some advice.
I recently installed a towel radiator in the bathroom to replace the old radiator. The towel radiator will not heat up. So far I have tried:

• Turning off all other rads
• Bleeding all rads
• Checked that TRV and lock valve are fully open
• Closed both valves, dissipated residual air pressure from bleed nipple, removed bleed nipple, screwed in a drain cock with a hose attached, opened trv side and allowed gurgling to stop. Repeated on lock side. (At this point warm water flows into rad), close valves, remove drain cock, bleed nipple back in, bleed air, open both valves, turn heating back on...........COLD!!

Am I missing something here? Could one of the valves be faulty? If so how is it that warm water actually comes through when I do the above?
Does it matter which side the Trv and bleed nipple are on? Currently, both are on right-hand side of rad
Went under house and could feel that the 22mm pipe which feeds the 15mm pipes for this rad is warm but the 15mm pipes are cold.

Property is a bungalow with Combi in loft

 

[Riley]

I realise your pic is rough but is it a one pipe system ie just one 22 mm pipe feeding both flow and return

 

[Gavin Rafferty]

I realise your pic is rough but is it a one pipe system ie just one 22 mm pipe feeding both flow and return

Hi Riley, yes that's right one 22mm that feeds both 15mm flow and return.

 

[ShaunCorbs]

you havent teed both into the same pipe have you?

and how come your rad in the bedroom is teed off the same pipe?

 

[Gavin Rafferty]

you havent teed both into the same pipe have you?

and how come your rad in the bedroom is teed off the same pipe?

Hi Shaun, didn't change any of the original config, literally swapped one rad for the other using same pipes....it seems in this bungalow all the rads flow and return from the same 22mm ... is that what you were asking?

 

[ShaunCorbs]

your drawing shows two pipes?

 

[Riley]

So your new rad is exactly the same width as old???

 

[Gavin Rafferty]

your drawing shows two pipes?

Sorry Shaun, so there's one 22mm (blue pipe) and from this comes two 15mm (green pipe) per rad. thanks

 

[Riley]

If it’s a one pipe system would it require different rad valves?? I know they have to be specific TRVs but I do t know if there is a towel rail equivalent?

 

[ShaunCorbs]

sounds like a one pipe system new towel rad wont work

 

[Pickwickpick]

sounds like a one pipe system new towel rad wont work

Managed to get one to work a couple of weeks back, customer insisted on going ahead without converting to two pipe system against my advice. Used swept tees and re routed the main pipe to so that the pipes feeding the towel rad were less than 1m in length.

In this scenario between distance from 22mm pipe and the number of bends between the 22mm & the towel rad its not going to work. Swapping the tees for swept ones and altering the pipework might allow it to work.

 

[Riley]

Managed to get one to work a couple of weeks back, customer insisted on going ahead without converting to two pipe system against my advice. Used swept tees and re routed the main pipe to so that the pipes feeding the towel rad were less than 1m in length.

In this scenario between distance from 22mm pipe and the number of bends between the 22mm & the towel rad its not going to work. Swapping the tees for swept ones and altering the pipework might allow it to work.

Might

 

[Pickwickpick]

Might

Definitely no guarantees on that one!

Converting to two pipe or going back to an equivalent rad to the one taken out by the OP would be the better option.

 

[Gavin Rafferty]

Definitely no guarantees on that one!

Converting to two pipe or going back to an equivalent rad to the one taken out by the OP would be the better option.

Thanks everyone. just so I know, why would a 'normal' radiator work fine and a towel one not?

 

[Riley]

One pipe systems are reliant on flow and lack of restriction.

 

[Gavin Rafferty]

Thanks all, I think re-routing the 22mm so it runs under the rad and reduces the 15mm tails would be my easiest 1st option then. Do you know if JG do a swept tee?

 

[Riley]

I would strongly doubt it. It may not work stilleven with copper swept tees. The rad valves you have are very restrictive and depending on the internals of the towel rad itself they can also be restrictive in order to get an even heat

 

[Pickwickpick]

Thanks everyone. just so I know, why would a 'normal' radiator work fine and a towel one not?

Less restricted flow of water compared to a towel rad so the hot water is able to convect through it.

 

[Pickwickpick]

Thanks all, I think re-routing the 22mm so it runs under the rad and reduces the 15mm tails would be my easiest 1st option then. Do you know if JG do a swept tee?

No there isn't a speedfit swept tee, its hard enough getting your hands on an e/feed one.

With regards to rerouting the 22mm, you've got nothing to loose bar some time, but its much more likely not to work than it is to work imo. It could also be as @Riley says that the internals on the towel rad you have installed are too restrictive, if that's the case no alterations to the pipework or swept tees will get it working I'm afraid.

 

[SimonG]

Don't do the pipework in plastic.