Speedfit isolation valves - ok for Mains and hot?

well they are spec'd up to 65deg which is as hot as hot water should ever be. In any event an isolated hot leg doesn't get or stay hot. You need to chose between the tap version and the screwdriver operated version. Horses for courses, do you want to operate them with or without a screwdriver. I could add upside down in a dark cupboard. Never had a problem (except engaging the screwdriver upside down in a dark cupboard).

Jim A

On 19 Feb 2007 05:25:03 -0800 someone who may be "stevep" wrote this:-

Why?

According to the manufacturers they can be fitted to mains pressure and hot water pipes. However, they would say that wouldn't they?

I'm sure there are millions in use around the world, but I wouldn't use one in my house as I have seen what happens when they fail.

I really would not recommend Speedfit's screwdriver-operated isolation valves. Complete rubbish. The plastic they are made from is so soft that the screw head deforms as soon as you touch it with a screwdriver, and then it's set on (or off) for ever. Their hand valves are much better, but much bigger too. I'd use someone else's , although I have no experience of any other pushfit manufacturer.

One thing atht has always worried me about Speedfit in hot water applications is that they say they are not suitable for constantly circulating systems such as hotels, large buildigs etc. Why would that be I wonder?

With hindsight, I'm not sure I'd have used Speedfit for my hot water. It was quick to install, but there's the constant nagging worry that one of the joints is going to pop off. Copper brings peace of mind, at least to my mind anyway!

Jon.

Speedfit do a metal bodied version for central heating applications (the plastic ones are specified as not being suitable for CH). I haven't used them. I agree about the their regular valves: plastic like ripe brie.

If I really need a push-fit isolation valve I use the ones with handles which are OK, but mostly I find compression valves easier to use if the pipework has to be bent out of line to get the valve in which will snag on and wreck the O-rings in a push-fit.

speedfit, normally for the sames reasons, damge or poor installation. Personally I have no preference for either.

On Mon, 19 Feb 2007 19:18:27 GMT someone who may be "Stephen Dawson" wrote this:-

Soldered and compression joints rarely, if ever, come apart totally in an instant, leaving open ended pipes out of which water can flow.

and that was user error by me, they don't work on chrome pipe. And it says that in the booklet. I just forgot.

Regards

Steve

I have. Thankfully low pressure, cold water. It was a slow dripping that stared about a year after installation, and went undetected for perhaps 2-3 weeks. Made a right mess of part of a new kitchen!

Cause? Hard to say - probably my fault. Probably didn't push the pipe far enough into the fitting. But I've never had a soldered copper fitting go wrong, and I've done dozens and dozens of each. To my mind the problem with Speedfit is that you can get it wrong, and it will work OK for a while, then leak. Copper tends to be obvious when it's wrong, and lasts for ever if it's right.

I'd use it again, but more carefully.

Jon.

On 20 Feb 2007 00:14:50 -0800 someone who may be "Tournifreak" wrote this:-

When they fail suddenly on mains pressure water they are most spectacular, if it happens while the house is unoccupied it will get very wet.

Indeed. Different failure modes to push fit fittings.

and what failure modes are you suggesting cause (1) Speedfit in particular or (2) pushfit in general fail?

These are engineered products which if they fail when used properly must be for a reason. Surely the reason, if any, is the issue not the product.

Jim A

Not going to disagree that these joints come apart totally in an instant. That should always be prevented by proper support and clippage anyway. But in the circumstances posed by the OP, a soldered made by a relatively inexperienced person with wet pipework would have a very high chance of leaking. A pushfit joint made properly purely by following instructions would have a very low chance of leaking even with wet pipework.

Jim A

On Tue, 20 Feb 2007 09:10:28 GMT someone who may be "Jim Alexander" wrote this:-

A soldered joint is held by the solder all the way round. A compression fitting is held by an olive and nut. Both are extremely unlikely to suddenly fail completely.

Push fit fittings are held by a few little bits of metal that, in theory, grip the pipe strongly enough that water pressure will not push the thing apart. I prefer solder or a nut, others may laugh at this "old fashioned" attitude but I will continue to adopt it.

On Tue, 20 Feb 2007 09:18:46 GMT someone who may be "Jim Alexander" wrote this:-

It would have a chance of leaking. However, this leaking is not likely to be at a great rate. More importantly, the chances of such a joint appearing to be fine and then suddenly failing after a week or a month are negligible.

As would a soldered joint made following the instructions in any book on the subject. If they used a compression fitting they wouldn't even have to dry the pipes.

Under freezing conditions, a compression joint can pull out of the olive. Under similar conditions a soldered joint is more likely to split the pipe.

I haven't seen this for a number of years though. An instance of the former was a header tank in an unoccupied (but furnished) house fed via a compression elbow. The next door neighbour alerted the owner when she started to get water through the wall. The flooded house (and contents) were completely wrecked, but fortunately was insured.

Thanks for all your replies.

I had a nagging doubt about plastic isolation valves and your comments will steer me away from these.

Cheers Steve

Horses for courses. I'd think twice about using a push-fit coupler above a lath and horse-hair plaster and fancy corniced ceiling over a room full of priceless furniture, but if I'm making a rat's nest of connections here there and everywhere at the back of a kitchen sink on a solid ground floor where you need to be a yoga guru to even reach in to the pipework then pushfit wins hands-down.

On Tue, 20 Feb 2007 12:56:07 GMT someone who may be wrote this:-

If the pipes are not protected against frost. However, under the same conditions the little bits of metal in a pushfit connector are going to provide even less resistance to the joint coming apart.

That would be to the good strangely enough if that is what feezing would cause. A push-fit pipe has to be forced out at least 10mm before it will fail after thawing. Though push-fit joints are not proof against freezing, unlike copper pipe, freezing won't burst polyb pipe. As others have opinioned there is an element of horses for courses here. I'm not criticising advocates of solder or compression but I am comfortable with my own installed push-fit pipework. Not a huge fan of Speedfit over Hep but its very low insertion force has it's advantages in really difficult locations.

Jim A

On Tue, 20 Feb 2007 16:05:18 GMT someone who may be "Jim Alexander" wrote this:-

Plastic pipes can also be joined by compression fittings, so the point is void.