Reconnecting a Radiator Tips

I find a good 'cheat' on tricky joints is a wipe of silicne sealant over the threads, it lubricates and seals without gluing the damn joint solid.
The trick with the tape is to wind it on in the right direction so that it stays down smooth as the joint is tightened... it usually takes 3 tries.
Del

As Del says about the tape - it's all in the direction. Wrap it in the same direction as the mating part goes on - e.g. clockwise if looking at the end of the thread. Don't use too much.

Cleanliness is essential! One little bit of grit can ruin the seal.

Yeah if you have problems applying teflon tape they make it in a paste you just brush on to the fittings.

Rectorseal is good for hot water radiators. It's probably good for other pipe joints, too, read the label. It's a paste sold in cans with a brush attached to the top.

What sort of radiator? or rather what type of connections - screwed or push and clamp? If screwed is it a flared fit or flush face fit?

Screwed flush face - tape or paste, and I'd go with paste, there are a number suitable for hot conditions.

Flared should not need anything. If its cu, anneal the flare before resealing, this makes it soft and 'pulls' into the fitting when tightened creating a seal.

push and clamped - got a wee bit of problem if your looking at tape then. Check your hose sizes.

Teflon tape is great stuff. If you're young enough and wrap it in the clockwise direction for right-hand threads, you'll be OK. Those old EEs are the only ones who seem to have difficulty.

http://www.google.co.uk/#sclient=psy&hl=en&source=hp&q=Applying%20ptfe%20tape%20to%20pipe%20joint&aq=&aqi=&aql=&oq=&pbx=1&bav=on.2,or.r_gc.r_pw.&fp=7fda8db40d2b43f8&biw=1325&bih=783&pf=p&pdl=3000&safe=active

I suppose your talking about cast iron radiators of the last century.

It may be expensive, but I would put a new valve on. Here in the USA I pay $22.00 for 3/4", and about $44.00 for a 1 1/4".

I use rectorseal, but any good pipe dope will work - and I would stick with something that says thread sealer on the can. Tape is OK, but paste faster.

Once you get it hooked up - which can be a trick because the pipe end doesn't always match up to the hole in the radiator - just get it good and tight. Unless you your a pipefitter by trade, it is unlikely you can get it too tight without a big wrench or a cheater valve.

If the connecting piping is holding the radiator off the floor I will usually shim the radiator feet. Union joints - that's the one with the nut on one side - can take a lot, but I suppose over time it could get back.

You said reconnect - make sure the threads going into the wall or floor are tight too. It would be a shame to have a leak, however small, behind the wall. I have seen a lot of boiler systems that just couldn't hold pressure. It is a pain the be filling the system all the time, and then you might have to bleed the radiators too.

It is brute-work, usually you have to jack the radiator around while you tighten the last turn on the valve so the Union joint matches up. You sort of turn them together at the same. It's sort of hard to describe, but you'll see that there us interference between the two halves of the Union joint on either the valve or the other end unless you twist the radiator out of the way. I always just muscle the radiator sort of out of the way a few inches, or degrees/radians whatever.

Of course, if your putting on a new valve or the other other end, you will need a "spud" to catch the shoulder on the inside of the bell-side of the union.

Have fun!!!

Thanks for all the input, I am going to have a go at it this weekend.

It's not a big radiator, just a relatively modern one that got disconnected so I could decorate. I'm just not very good at getting a good connection. My outside tap and the garden hose still leeks. it's not a problem there, but on the heating system inside, it will be a problem.

I hadn't heard of the paste before and googled it and someone said not to use the paste and tape together. Is this true. I often go for the belt and braces solution, not always the best way though.