Checking gas.

The instructions for the pressure gauge incorporated in the Gaslow regulator seem to suggest that a couple of minutes are sufficient, but I find that surprisingly short.
 
davidpbo said:
I have a simple gas installation. Camping gas bottle with top regulator. Tail to copper pipe via suitable fitment to isolator valve under cooker to fitting and tail.

Using a manometer with system pressurised how long does it need to hold a constant pressure for please?
Click to expand...

The old Corgi manual said 5 minutes ......... but note that you pressurise the system , close the valve and then burn off a little gas to lower the pressure slightly. This is so that the small reservoir of high pressure gas in the regulator or a very small leakage past the valve cannot hide a small leak.

From the Corgi manual:-

Testing the complete installation.​
​
(a)Turn off all appliance control taps including any pilot valves. Ensure that fold down lids on cooker hotplates are raised so that any safety shut off valves on the supply to the cooker hotplate taps are open, but control taps are shut. Isolate the LPG supply.​
​
(b)Connect a "U" gauge to the test fitting, if present, or alternatively, to an in-line test tee.​
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(c)Open the main shut-off valve to achieve lock-up pressure, then close the valve.​
​
(d)Light one appliance burner and allow the pressure to fall to 30mbar (Propane) or 20mbar (Butane).​
​
(e)Turn off the appliance control tap and leave for 5 minutes. Record the pressure in the "U" gauge.​
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(f)Leave for a further 5 minutes, and re-record the pressure on the "U" gauge. There should be no discernible pressure drop in the system. (See Note).​
​
See also section 10 here
https://montymariner.co.uk/wp-content/uploads/2017/03/ISO-10239-Small-Craft-LPG-Systems.pdf


​
 
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I need to re-visit to that test procedure. I don't know whether I got it wrong. There was a 3mb drop over 5 mins I don't know whether it had any relevance but there are some serious showers passing over.

Got to Largs and after an afternoon into evening rigging came to warm pasties- no gas. Plenty in cylinder. Disconnected pressure pipe from cylinder top regulator and with cylinder in the cockpit, turned the shut off valve on briefly and still no gas. I will try with a new cylinder tomorrow but suspect the regulator which was loose in the gas locker travelling up had failed. It is time to replace anyway.
 
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davidpbo said:
I need to re-visit to that test procedure. I don't know whether I got it wrong. There was a 3mb drop over 5 mins I don't know whether it had any relevance but there are some serious showers passing over.

Got to Largs and after an afternoon into evening rigging came to warm pasties- no gas. Plenty in cylinder. Disconnected pressure pipe from cylinder top regulator and with cylinder in the cockpit, turned the shut off valve on briefly and still no gas. I will try with a new cylinder tomorrow but suspect the regulator which was loose in the had locker has failed. It is time to replace anyway.
Click to expand...
You could not explain a fall in reading of 3mb in 5 minutes by either a drop in temperature or a change in barometric pressure
 
VicS said:
You could not explain a fall in reading of 3mb in 5 minutes by either a drop in temperature or a change in barometric pressure
Click to expand...

No I thought that was the answer. More investigation to be carried out. I suspect operator error. I don't have the manometer with me, I do have a gas detector wand and a very limited number of joints in copper pipe which have not been disturbed other than by the replacement of the 2 rubber tails.

We are fairly conscientious about turning off at the bottle, at night, when sailing and when off the boat.
 
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