In a message dated 08/07/2009 00:08:41 GMT Daylight Time, cfharris@erols.com writes: But I'm puzzled! First you tell me you have never seen an O-ring with a jamb nut in a heating system, and then you tell me that your system, presumably without any such O-ring seals, doesn't leak??? ------------------- I think that's because you're talking about different things. When Bjorn comments... "Cu tube joints are madewith "nut", "support cylinder" and a "squeeze ring"....... He's referring to a standard compression fitting, with the brass or copper "squeeze ring", more usually called an olive or compression ring, having tapered ends and being compressed around and into the copper pipe surface as the nut is tightened. Other than soldered joints, which are also still used, this is the standard fitting here for gas or water in domestic installations. When fitted properly, and they're very easily fitted, these shouldn't leak at all. If they have a downside it's that same thing that makes them work so well to start with, the ring bedding itself into the outer of the copper pipe, especially as there can be a tendency to overtighten despite warnings to the contrary. For the ring to be fully effective it needs to be installed over a "fresh" section of pipe. When working on existing systems, particularly those that have been installed for some time, it may be necessary to replace lengths of pipe, or at least cut back and insert a fresh short length in order to remove ends where the fittings have been previously installed I have also never seen an O-ring with jamb nut in a domestic heating system and don't think steel pipe has been used here in regular domestic heating systems since "central heating" took off in the 1960s/70s. Steel pipe, often it seems referred to as "gas barrel" even if not being used for gas, is still common in industrial situations but copper is the norm for gas and water in domestic situations with pipe sizes varying to suit flow and equipment fittings. Domestic radiator type water heating systems traditionally make use of 25mm and 15mm copper pipe but systems using plastic sheathed 10mm copper pipe are becoming more common, with the sheath being cut back to allow entry into the fitting.. As compression fittings are very much the norm here I'm surprised that you don't seem to have encountered them in the US. Is it possible that what is being supplied to the US from Europe is more dictated by US plumbing practices and regulations than by what we'd normally prefer to use ourselves?:-) regards Nigel GM8PZR

Hi Nigel, > He's referring to a standard compression fitting, with the brass or copper > "squeeze ring", more usually called an olive or compression ring, having > tapered ends and being compressed around and into the copper pipe surface as > the nut is tightened. > Other than soldered joints, which are also still used, this is the > standard fitting here for gas or water in domestic installations. > > When fitted properly, and they're very easily fitted, these shouldn't leak > at all. We use them here in the US, for small water fittings... such as refrigerator ice makers, and toilet tank fills. They work just fine. I always put a little non hardening pipe compound under the ring to prevent seepage that can occur on poorly made tubing that has mandrel marks left over from drawing the tubing... I never used to have to do that, but the Chinese and Mexican manufactured toilet fill tubes we get these days are awful. ... > I have also never seen an O-ring with jamb nut in a domestic heating > system and don't think steel pipe has been used here in regular domestic heating > systems since "central heating" took off in the 1960s/70s. Good! The UK must be using more sane methods. I haven't been talking about steel pipe, I have been talking of straight pipe thread on fittings, such as shut-off valves on radiators, and fittings on manifolds. > Steel pipe, often it seems referred to as "gas barrel" even if not being > used for gas, is still common in industrial situations but copper is the > norm for gas and water in domestic situations with pipe sizes varying to suit > flow and equipment fittings. Steel pipe is mandated for gas systems in many areas of the US. I am in one such area. It works fine, and is 100% reliable. Copper tubing is only used by propane installers, and they form their own codes. Compression fittings seem to be universally outlawed for gas, though. Formed flare fittings are the norm on copper gas tubing. ... > As compression fittings are very much the norm here I'm surprised that you > don't seem to have encountered them in the US. As I said earlier, I have encountered plenty compression fittings. They are not what I have been discussing. > Is it possible that what is being supplied to the US from Europe is more > dictated by US plumbing practices and regulations than by what we'd normally > prefer to use ourselves?:-) No, these are bog-standard parts ordered directly from the manufacturer's catalogs, and imported directly into the US. There was no US code interference in these transactions. The work was done as directed by the manufacturers. You see, I happened to think the Europeans are the masters of the universe when it comes to hydronic heat. It is rare to find hydronic heating in the US because our climate requires both heating and cooling in most areas, and it is much cheaper to install a single forced air system that does both the heating and cooling than it is to install two separate systems. In the US, hot water and steam heating systems are generally found only in houses that were built before central air conditioning was common. It's been fun, but we have probably taken a long enough vacation from time and frequency issues. I think it is past time to wind this subject down. -Chuck Harris

Soldered copper is certainly not allowed for gas. There are special, flexible copper and fitting systems are, but not everywhere. -John ========= [snip] > Steel pipe, often it seems referred to as "gas barrel" even if not being > used for gas, is still common in industrial situations but copper is the > norm for gas and water in domestic situations with pipe sizes varying to > suit flow and equipment fittings. [snip]