Radiator Leaking - What am i doing wrong?

[ScubaCollie]

Hi All, ivw done a bit of DIY plumbing throughout the years and never have i had so much hassle as i have today.

My wife purchased one of these

Santorini Anthracite Flat Panel Heated Towel Rail 650x400mm

Keep your bathroom towels warm with this Santorini Anthracite Flat Panel Heated Towel Rail 650x400mm. Made from high-quality materials and available at a competitive price.

www.bathroommountain.co.uk

It didn't come with valves so I popped into my local plumbers merchants yesterday and was told the below would do the job.

I've never seen a thread like that before (it almost looks like it's serated) so wasn't sure if can put PTFE tape on it or not.

I put the tape on, and it started leaking.

I took the tape off, reapplied with even more tape this time and it still leaked.

I then took it off, and this time applied joint compound only with no tape, and it held for about 15 mins and then started leaking.

I also don't have any drain valves on any of the rads and have a Combi therefore it's a nightmare draining the system down and getting soaked everything it's like the Trevi Fountain!

Anybody have any ideas what's going on?

I'm nipping it up nice a tight and when it leaks I'm trying to tighten up even more with it on the wall and it ends up going to max with no more ability to tighten.
I've been at it all day, had the rad off and back on the wall about 5 times and sprayed with the Fountain each time also.....

I'm wondering if I need to purchase the valves off that website but have just spent 30.00 these ones.....

 

[oldbuffer]

1. Try using Loctite 55 pipe sealing cord instead of PTFE.
2. Those threads are "roughed up" as the instructions for Loctite 55 suggest.
3. Loctite 55 should be wound around the threads, and also across the threads. I'd start with 4 wraps across the threads (at about 90 degrees to each other) and 12 wraps around the threads.
4. If you hold the valve tail with the threads facing you, wrap the cord around clockwise so that screwing the tail in doesn't unwind it.

As an alternative you could use Loctite 77 or Flomasta pipe seal. These are liquids. Run a bead right around the second and third threads in from the radiator end of the tail, then screw the tail into the radiator and leave 30 minutes or so. You would need to remove all traces of the PTFE tape from the male and female threads, which must also be grease free.

 

[ianmcd]

The problem with these rads is the tappings are slightly oversized, you need to use an awfull lot of PTFE to get them to seal, I usually do about ten wraps tighten and remove, leave exisiing PTFE on the thread and another ten wraps then tighten again, if you have Gastight PTFE it is thicker and will give better results

 

[ScubaCollie]

Many Thanks to you both, will go out today and get some of that loctite 55 and also a wheelbarrow full of PTFE tape just in case!!!

I'm also going to use that existing thermostatic valve on one side (I understand it doesn't matter which side? And also I'm going to get another typenof valve for the other side with a drain nipple on it that would be fine? Obviously this would need fitting to the supply side? That side must be the side that had the most pressure in that sprayed like the Trevi Fountain therefore I know what side it is!!!

Thanks again to you both will report back later if we managed to get it done in not

 

[ianmcd]

I'm also going to use that existing thermostatic valve on one side (I understand it doesn't matter which side?

If a Bi-directional TRV then no doesnt matter, most modern ones are, but double check the rad some (not all) are flow side sensitive as they have an internal baffle to distribute the heat to the top of the rad, rad will be maked flow if it has a baffle

 

[ScubaCollie]

Many thanks. I can't get the Loctite 55 anywhere today.......however Screwfix do this one, will this be any good?

Flomasta Pipe Sealing Cord 80m - Screwfix

Order online at Screwfix.com. Nylon and silicone thread sealant for gas and water applications. Creates a non-curing, immediate full-pressure seal. For use with water up to 85°C. Ideal alternative to tape, hemp and pastes. FREE next day delivery available, free collection in 1 minute.

www.screwfix.com

 

[Nige F]

That'll be fine

 

[ScubaCollie]

I can't seem to find a straight valve with a drain plug built in?

 

[terryplumb]

You would need to introduce an in line drain cock between the radiator and the valve. Such as Screwfix code 3450R

 

[ScubaCollie]

You would need to introduce an in line drain cock between the radiator and the valve. Such as Screwfix code 3450R

Many Thanks Terry, this really isn't an option for us as already drilled the fitting holes through brand new tiles for the rad.

What's the best way of draining it down off a Combi with not a single drain plug fitted to any rads? I've been sprayed by a fountain of water 5 times yesterday already!

Can it be done on the boiler somehow? Photo attached of make/model?

 

[terryplumb]

Depending on the pipe layout and boiler position only some radiators would drain ,essentially those on floors higher than the boiler.
If there are any exposed heating pipes on the lowest level of the system ,you could fit a drain cock into the pipework.

 

[ScubaCollie]

Hi All, just wanted to say a big thank you to you all, I managed to get the rad installed and the radiator tails held 1st time with 20 wraps of PTFE tape on them!!

I can't believe they needed that much and I was still able to thread them into the rad.

One thing though I did have a problem with, was the feed into the rad from the floor pipes, I had to end up using PTFE tape on them as well because they just would not hold the water back without it. And even then the left one kept weeping and i had to nip it up about 5 more times over the course of a couple of days, but it has no finally held without any leaming at all, all 6 x joints are now as dry as a bone!!

As per the attached pictures it was the left pipe I had a problem with, and I noticed it looked different compared with the right one, and then I found a small brass cylinder part inside the old valve, looks like it came off that pipe on the left. I therefore put it back on it (just loosely) before I installed it as otherwise the nut on that left pipe kept dropping down the pipe and wouldn't hold up top.

If I ever need in the future to replace that pipe end how do I do that on these pipes? As they don't look like your standard plastic pipes?

Pictures below of left and rifht hand pipe see how they look so different?

Even after I put that brass cylinder back on the left pipe (didn't take photo if it unfortunately) it still looked a lot different to the right.

 

[Madrab]

Gastight PTFE it is thicker and will give better results

Find it to be far better - 7 wraps then no issues.

If I ever need in the future to replace that pipe end how do I do that on these pipes? As they don't look like your standard plastic pipes

They are compression reducers - 10mm to 15mm - any time old fittings are being re-used tape/thread/compound should be used on the olive as they will never fit back the same way again and will be prone to leaking.

As far as replacing the pipe end is concerned you can't, well you can but you need to cut off the old fitting/reducer and that's nigh on impossible without nicking the pipe. The only safe option would be to cut the pipe and re-extended.

 

[ScubaCollie]

Many Thanks therefore I did right by using PTFE tape on them?