gas installation

[OptedOut]

I am not sure why the "metel to metal" contact should worry you, this is standard proceedure for gas fittings. The threaded Calor Gas bottle connection is really no more than a fixed olive compression fitting, and is almost identical to the fittings you will find on your gas central heating boiler and gas meter at home. If they are leaking, the mating faces on your pigtail pipes may be damaged and need replacing.

 

The problem with this type of fitting is the vulnerability of the male half cone, it is easy to scatch or damage, the cylinder seating is fairly well protected.

It is common in industry to have a leak at an acetylene or oxy cylinder at this connection sometimes resulting in a small fire at the acetylene cylinder regulator.

The standard cure was to grind in the fitting whilst the nut was slightly slack.

[David Schweizer]

You also need to take into account temperature variations.

Yes - see my earlier post.

 

One of the problems which surveyors who are not trained in gas and hydraulics fitting do not seem to understand is pressure fluctuations due to temperature change and can mistake the minor variations in the WG reading as a problem with the gas supply and they do not know how to compensate for it.

[ditchcrawler]

Yes - see my earlier post.

Sorry I missed that

[Radio-Ga-Ga]

Going back to the original post it could be worth checking the cooker taps for an intermittent leak, just spray some leak detector onto the jets (with all the taps off) might be good to do it when your usual test has shown the pressure has been lost, and before you move any taps

[Guest TerryL]

Come on, you're not that old. A perfectly ordinary 1972 MG Midget has no ammeter. After all dynamos were still the standard fitment for most cars at that time.

 

Richard

 

It's the only way to travel...

There were still plenty of dynamos about then but all my vehicles from the late sixties including an MGB had alternators which is when they generally stopped fitting ammeters as charging was possible at idle so you didn't have to turn off the headlights to get a bit of charge in. Halogen headlights were also fitted about that time.

[kerching]

Does anyone still snift the gas cylinder before connecting the regulator.

[OptedOut]

Does anyone still snift the gas cylinder before connecting the regulator.

 

Yep.

[robkg]

It goes as follows

 

bottle - manual change over valve - bubble tester - throught bulkhead connection (pipe is continuous) - drop test point - tee - flexible hose to oven and copper pipe to hob ( both legs after the tee have isolating valves.

I installed my own gas system, which consisted of auto changeover valve, pipe through gas locker bulkhead to isolator valve on well deck, pipe through cabin bulkhead and under gunwhale to cupboard, through test point to compression tee then flexibles to oven and hob. Note that I did not fit seperate isolating valves on each branch of the tee. My surveyor initially questioned this. I explained that my understanding of the BSS regs. stipulate that each appliance requires an isolating valve. An oven and hob located one above the other are considered to be one appliance and as the only appliance on my boat, can be isolated by the valve on the well deck. I also explained my rationale for not fitting seperate isolating valves being that I am providing more joints and therefore more places to potentially leak, and in the vent of a leak, I would never use the valves in the cupboard (especially not one of them so that I could continue to use the other part of the appliance!), I would always isolate the appliance using the well deck isolator.

After taking advice the surveyor agreed with my views and passed the installation.

The point here is that you may be able to simplify your installation and reduce the number of potential leak sites.

 

One other technique I adopted was to use brass bulkhead compression fittings, but I modified them by drilling out the internal shoulder, then threading the copper pipe through without cutting it. By tightening the nuts onto the pipe, I eliminated any chafing from vibration. This eliminated any risk of leaks at the bulkheads.

[jeb]

Have just returned from the boat and having just had the gas installed a few days ago by a corgi registed fitter I did the simple test of lighting the stove and see if it would burn for 20 seconds or so before the pressure dropped. Result...... would not even light . The gas was turned off last night at around 6ish and I tried the test around 1 this afternoon. A bubble tester is not fitted so cannot try that, so does this test prove anything ? I do not really want to bring the fitter out for no good reason as this would be a total waste of money, however if there is a leak that would be down to him.

[alan_fincher]

I'd expect the system to have held pressure overnight, and that the gas should light for a bit.

 

What you have seems indicative of a small leak. (Although if no bubble tester, your installer should have checked it with a manometer before they passed it over).

 

There are two (at least) on here that will vehemently disagree with me, but a bubble tester would tell you this very quickly, (OK, not where the leak is, but that you have one), and I think they should be standard fit on all installations.

 

If you don't want to get the man back without evidence, try brushing/spraying a 50/50 mix of water and washing up liquid on every single joint in the system. It's sometimes hard to see if it's a slow leak, so you may need to squint at each joint for a while, but if you get "lucky" you'll find one blowing bubbles. If it's a compression joint, with a copper olive, and extra quarter turn tweak with a spanner will usually seal it, (unless it's been badly over tightened already).

Edited November 13, 2008 by alan_fincher

[jeb]

I'd expect the system to have held pressure overnight, and that the gas should light for a bit.

 

What you have seems indicative of a small leak. (Although if no bubble tester, your installer should have checked it with a manometer before they passed it over).

 

There are two (at least) on here that will vehemently disagree with me, but a bubble tester would tell you this very quickly, (OK, not where the leak is, but that you have one), and I think they should be standard fit on all installations.

 

If you don't want to get the man back without evidence, try brushing/spraying a 50/50 mix of water and washing up liquid on every single joint in the system. It's sometimes hard to see if it's a slow leak, so you may need to squint at each joint for a while, but if you get "lucky" you'll find one blowing bubbles. If it's a compression joint, with a copper olive, and extra quarter turn tweak with a spanner will usually seal it, (unless it's been badly over tightened already).

 

Thanks Alan,I will try that tomorrow. The man did check the system with a manometer before he left but no where near 20 mins as someone mentioned in an earlier post.

[alan_fincher]

Thanks Alan,I will try that tomorrow. The man did check the system with a manometer before he left but no where near 20 mins as someone mentioned in an earlier post.

Well I would say I think a bubble tester will show a small leak far faster than a manometer.....

 

But, there are others who disagree with that, I know.

 

To me, if one bubble passes through the bubble tester, then "one bubles worth of gas" has leaked from the system somewhere, (and should not have). Nice and simple, and a test you can do yourself each time you turn the gas on to get a nice comfort feel, not wait 4 years with leaking gas until a BSS finds it.

 

[/end_of_preaching Smiley!]