Gas Test Pressure

You should always use gas to test the integrity of a gas system in the end. If the bottle valve is leaking gas past this will show on on the manometer making the water level rise in effect this would be a Fail and the bottle returned to the supplier! This is all part of the test!
Honestly though and i know it sounds difficult but you dont sound like your truly aware of what you are doing! (not meaning to sound nasty) I urge you to get profesional help!!
 
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you dont sound like your truly aware of what you are doing! (not meaning to sound nasty) I urge you to get profesional help!!

[/ QUOTE ] All I am trying to do is establish what is required and identify the pitfalls.


You say gas should be used to test the system but I have seen professionals pressurise a system by blowing into it!

I'm not testing any gas systems so on that score I don't need any professional help.
 
Going back to first principles wouldn't a test using air be better than gas?I'm thinking relative molecular sizes here.(well maybe not in the time frame we're talking about).
 
Usual method is to connect a manometer, turn on the gas slowly and let the pressure reach 20mbar = 8" water = 0.3 psi.
Turn off gas, allow 1 minute for temperature stabilisation, don't allow pressure to rise above 25mbar = 10"water.
Ensure no loss in the next 2 minutes and no smell of gas.
 
I welded up a joint on my cooker once and it held about 18" of water overnight in a manometer so I was reasonably happy with it!
 
Mike,
I said I would come back if my post needed correcting.

I copy from the Corgi LPG for caravans and boats, page 101.

"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.

(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.

(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).

(g)Release the pressure in the system by lighting an appliance burner. Disconnect the test fitting or test tee.

Note. If a pressure drop occurs, re-pressurise the system and test all joints with non-corrosive leak detection fluid. Repair any leaking fittings and repeat the soundness testing procedure. Test all joints made after the soundness test with non-corrosive leak detection fluid."

This is from the Corgi bible.

The soundness testing procedure is another section.
 
Mike,
I said I would come back if my post needed correcting.

I copy from the Corgi LPG for caravans and boats, page 101.

"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.

(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.

(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).

(g)Release the pressure in the system by lighting an appliance burner. Disconnect the test fitting or test tee.

Note. If a pressure drop occurs, re-pressurise the system and test all joints with non-corrosive leak detection fluid. Repair any leaking fittings and repeat the soundness testing procedure. Test all joints made after the soundness test with non-corrosive leak detection fluid."

This is from the Corgi bible.

The soundness testing procedure is another, previous, section.
 
Thanks for that philip.
I banged it up to 80 psi and it held for an age. Also put the old gas alarm back on and after about 20 hours it went off - always the middle of the bl**dy night!!! So I have finally given in and bought a new gas alarm.
All this time the gas bottles have been disconnected, so I have had to eat ashore - so sad.
 
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The soundness testing procedure is another, previous, section

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You can't leave it like that. What is the soundness testing procedure.?
 
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Do you really mean 80psi?? That equates to 5.5bar or 4158 millimeters of mercury.!!If so, and it held pressure, your system must be OK. (1 bar = 750 m/m).

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Got to be in psi Philip cos the only bar I know is outside the marina - but in staggering distance!!! Bars and mercury dont compute - sorry.
 
Most of the gas alarms available for fitting on boats are notoriously unreliable. So many things can set them off - a lump of blue cheese in our galley waste bin once triggered ours. Still, I suppose too many false calls are better than missing one genuine one.
 
More secretarial work!!

(n.b. this is before any bottles, regulators, are fitted and connected - just the pipework and appliances. - editor (me))

Page 98.
""U" gauge method.

At the open point, (where the regulator would be fitted - as I have to interpret the diagrams) connect a test tee. (the test tee has two valves - tap A to a bike pump, and tap B to the "U" gauge).

Attach the "U" gauge to one of the tube nozzles using a rubber tube connection and attach a bicycle pump or a similar inflating device to the other tube nozzle, (through a non-return valve).

(a) Turn on both taps (A and B).

(b) Introduce air into the installation pipework until the "U" gauge registers 70mbar.

(c) Turn off tap A (- to bike pump).

(d) Leave the system for 5 minutes to allow the temperature to stabilise.

(e) Note the reading on the "U" gauge.

(f) Turn off tap B (- to the "U" gauge).

(g) Leave for a further 5 minutes.

(h) Turn on tap B and again check the pressure reading on the "U" gauge.

(i) If the pressure reading has fallen, examine the whole of the installation to locate the leak(s).

Note: The method usually adopted is to restore the pressure in the system and check each joint by applying a non-corrosive leak detection fluid until the leaking joint(s) is discovered. Any defective joint(s) or fittings shoud be remade or replaced and the test procedure repeated. There should be no discernible pressure loss in the system."

Here endeth the second lesson from the Corgi bible /forums/images/graemlins/wink.gif

I shall be following this as I have to test my installation after the addition of a second bottle locker extension. I had to remove the pipework before work started.
 
Thanks Philip

That makes a lot of sense now testing the system with air at several times the normal operating pressure. I would think that if it passed that test, with the exception of the final connection to the regulator, it cannot possibly fail the previously described test with gas at below normal pressure.

I will file the info away now because sooner or later I want to upgrade my system, at least the gas bottle locker which drains into the cockpit and has no vent at present, which will involve breaking and remaking at least one joint. With that info I can test it all properly and be confident that it will pass a final inspection by a corgi man.

There remains one weakness though and that is the joint at the cylinder that we all break and remake every time we change the cylinder. It would be prudent I suppose to carry some of the leak detector spray and check it each time. At least it's in the locker I suppose so any leak should drain away safely.

I wonder what would make an acceptable non corrosive solution if washing up liquid is unsuitable. Probably a shampoo!

Thanks again Vic
 
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