Fitting trvs's to a bathroom towel radiator

[janturn]

Hi,

Can someone please offer some advice

I am in the process of fitting a pair of TRV's to a bathroom towel radiator which I recently purchased from Hudson Reed. I have connected the TRVs to the towel radiator using PTFE tape and some bathroom silicone. However. the valves continue to leak. They do not leak at the olive were they are connected to the copper pipes (inlet and outlet). Can anyone please tell me what I need to do to stop the valves from leaking as this will be the third time that the central heating system will need to be drained down, in an attempt to fix the leaking valves. Should I be using plumbers mate instead of bathroom silicone to stop the valves leaking or some other form of jointing compound

I hope that the i have been clear in my explanation.

I look forward to hearing from you.

[chrishutt]

Firstly why are you fitting a pair of TRVs to a rad? You only need one to do the job, and there's not much point in even one on a towel rail since the output is so low and it's often insulated with towels.

Secondly why do you need to drain the system down if the leak is between the valve and the towel rail? Just close the valves and re-do the leaking joints.

Thirdly you don't say which joint is leaking. Is it the threaded joint into the towel rail body or the compression joint to the valve body?

Finally I must ask, since your post indicates a low level of competence on your part, have you got the valves the right way round? The tail piece should go into the radiator valve.

[janturn]

Its the htreaded joint in to the towel rail body which is leaking. Your right I am not a professional plumber but have managed to plumb in an entire bathroom suite without any problems. When I say TRV's I meant to say radiator valves, sorry. They were supplied with the radiator, please see http://www.smrbathrooms.co.uk/acatalog/Hudson_Reed_300_Series_Towel_Racks.html

Sorry I have not been so precise as I should have been in my explanation of the problem.

Hope you can help.

[chrishutt]

It can be difficult to get a good seal on this threaded joint. Normally it would be sufficient to wrap PTFE tape around the male threads and then assemble until tight (which might require a special tool to engage with the inside of the tail).

However the threaded tapping on the towel rail may be slightly too large to get a tight joint. In this case you need to increase the amount of sealant - extra wraps of PTFE or a proper thread sealant. Ordinary silicone won't work because it needs a long time to cure.

[janturn]

Yes the fitting in slighly small. Will try to cure the problem by wrapping more PTFE on the thread plus sealant. Although the silicone is rapid curing yes it is taking too long to cure! I have not had to drain the entire central heating system to cure this problem

Many thanks for taking the time to relpy to my question.

Regards

[noonespecial]

No you should not use sealant and PTFE tape - use one or the other.

No do not use bathroom silicone it is not intended for that purpose.

Have you wrpped the PTFE tape in the correct direction eg in the direction of the thread (clockwise looking nose end on the thread)?

[janturn]

I have used PTFE tape only on the thread this time round. I think the problem is a loose fitting as I managed to wrap PTFE tape a number of times around the thread. There still appears to be a very very minor leak from each of the valves were they connect to the radiator. It appears to be very difficult to create a perfect seal. Thanks for the tip about the silicone.

[chrishutt]

You could try the old fashioned stuff - boss white and hemp. Could be difficult to get hold of hemp these days - you may have a buy a huge amount of it. Best to ask an older plumber is he can let you have a small amount.

[JPC]

boys....whats going on....

the rad tails are parallel thread and could appear as a "loose" fitting. u need some 10-15 wraps of ptfe on the tail threads that get screwed into the rad. they wont leak then. rad valves are just compression. do um dry or with some jet blue or similar. jobs a gooden

[janturn]

Would loctite 55 pipe sealing cord be suitable for creating a seal. I understand in can be used on hot water systems I have at least 15 turns of PTFE tape on the threads

[corgiman]

I am sure that Plumb centre do some flanged end unions for rads, and you can whack a washer on them.

They must do cos I have fitted them

or do as JPC says

[scatmanjohn]

I only ever use gas ptfe tape.
Single wrap with a 50% overlap.

It works for me