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Gas on or off?


ColinM50

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Risk is not always apparent. Some years ago I read of an interesting accident. On a cold, wet, day, a man was working in his garage, syphoning the fuel out of his car in preparation to removing its fuel tank (reason unimportant). He had drained the fuel into a bowl. His garage adjoined his house, and there was a door between garage and house. His central heating boiler was sited in the garage. For whatever reason, he then left the garage and went into his house. A short while later there was an explosion that blew out the end wall of the house.

 

His insurance claim was followed by an investigation, during which it was discovered that the central heating had been on while he worked, and that the boiler was of natural draught type. He had placed the bowl of petrol away from the boiler, to minimise the risk of igniting the petrol vapour in the garage. Petrol vapour being heavier than air, it sinks, and the garage was well ventilated. However, shortly before he went into his house the boiler had shut off under the control of the heating thermostat, leaving the flue warm, and still drawing air up through the boiler. With that air went petrol fumes, which gradually accumulated in the flue. Shortly after the man had entered his house the thermostat had called for heat, the boiler had fired, and with the concentration of fuel vapour in the flue by then explosive, the flue, and most of the wall to which it was attached, were destroyed.

 

The odd thing was that the man was an insurance risk assessor! :-D

 

So, why hadn't he spotted the risk? As the boiler had been firing while he worked, any fuel vapour in the air it ingested had been burned off as it passed through, with no adverse effects to suggest anything was wrong. It was only when the boiler stopped firing that the vapour had been able to accumulate in sufficient quantity to fill the flue with an explosive mixture - which the boiler had then ignited.

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william49, I do.

 

I use an Approved Workshop. The annual habitation check for gas covers: Regulator, gas hoses, pipework, and manifold; a gas soundness test; security of any LPG tanks; security of gas cylinders, cooking equipment including flame failure devices; heating appliance; fridge; water heater; gas dispersal vents are clear. These are marked in the Service Check sheet as Passed, Failed, N/A, Rectified.

 

Should appliances need servicing, then this is outside the AW scheme but the Workshop would carry out the work if asked.

 

 

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I'd have thought the answer to this fairly obvious but a couple of questions the o/p (and any others) can ask themselves;

 

Is it safe? Well your system should be.

 

Is it necessary? And this is the most important as i honestly cannot think of one logical reason why it would be.

 

As for leaving it on during ferry crossings....strictly forbidden!

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I’ve been motorcaravanning since 1998 and owned three motorhomes since then, and none of those vehicles has ever had a ‘habitation service’. However - as Brock says - checking a motorhome’s gas system should be part of any such service.

 

If you have a moden motorhome with a ‘smart’ fridge and/or a gas heating system certified for use while travelling, you cannot turn off the gas supply and make full use of the design capability of the fridge or heater. If you have an older motorhome with less sophisticated equipment, having the gas switched off while travelling won’t much matter.

 

(I honestly don’t know why this is seemingly such a big issue. People either choose to switch off the gas before travelling or they don’t and it’s most unlikely that argument will make them change their mind.)

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I have got into the habit of always turning the gas off - probably because of the ferry & tunnel regulations and I just extended their rules to when I drive. 

This year I used "Le Cube" propane and never really thought about it as there is no screw tap. Can I turn off "Le Cube" with the small tap or does that simply release the connector from the cylinder? 
Daft question really but as it's French I've been lazy & haven't bothered to try & translate the instructions.
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michaelmorris - 2017-12-15 5:43 PM

 

We always turn the gas off when travelling. Whilst the overall risk is probably quite low, the risk is very quick and easy to mitigate so it strikes me a bonkers not to significantly reduce a risk (even if it is a low risk) if it is quick and easy to do so.

 

I also always turn the gas off when travelling, mainly because I don't have any fancy secure-motion fitted.

 

Never had a habitation service but regularly check for any gas leaks using the permanently installed Gaslow pressure gauge.

 

In Germany the gas system needs checking every 3 years and a sticker placed on the rear bumper. Not a bad idea I suppose, at least it will at least identify rubber gas hoses which may be out of date.

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laimeduck - 2017-12-18 11:30 AMI have got into the habit of always turning the gas off - probably because of the ferry & tunnel regulations and I just extended their rules to when I drive. 

This year I used "Le Cube" propane and never really thought about it as there is no screw tap. Can I turn off "Le Cube" with the small tap or does that simply release the connector from the cylinder? 
Daft question really but as it's French I've been lazy & haven't bothered to try & translate the instructions.
“Le Cube” canisters (butane or propane) have a 27mm-diameter ‘clip-on’ valve. This valve can accept a 37mbar regulator (example here)http://laboutiquedebob.butagaz.fr/bob/clip-cube-propaneand - once the regulator has been attached - switching the gas on and off involves rotating the black ‘control-knob’ (on the right side of the regulator in the photo) while removing the regulator from the canister involves depressing the green knob on the left in the photo). The procedure is the same for a “Le Cube” (butane) canister and is shown in a video-clip herehttps://www.butagaz.fr/bouteilles-de-gaz/cube-butaneIf your motorhome has a fixed bulkhead-mounted regulator with a ‘full pressure’ adapter (example of one type here)http://www.gaslowshop.co.uk/product/gaslow-27mm-clip-on-adapter-with-top-elbow/at the canister-end of the gas ‘pigtail’, a 2-stage procedure will also be involved. Rotating the black knob/lever switches the gas on and off, and to remove the adapter from the canister will first involve rotating the knob/lever to its gas-off position and then moving the knob/lever to its ‘release’ position. I don’t know how much standardisation there is with this type of adapter when it comes to releasing it from the canister, but you either turn the black lever beyond its gas-off position or depress the knob inwards. Experiment - it ain’t rocket science.
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I have had my cylinder valves physically checked by a deck officer before boarding ferries to Shetland and since I frequently travel with Calmac I always have my gas turned off. Going off at a slight tangent my car has been checked a few times also for empty fuel containers at the ferry terminal since apparently if they have had petrol in them the remaining vapour is more dangerous than if they were full. Sounds s bit bonkers since the car deck is full of vehicles with partially full fuel tanks but rools is rools.( don’t bother correcting my spelling)
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ColinM50 - 2017-12-20 9:06 AM

 

Had a look in the gas locker and it seems I've already got one of those Truma gas protector thingamebobs so that's saved a few quid. (lol)

 

On our Truma crash safe (or what ever it's called in latest form) if the cylinder tap has been turned off such as when a cylinder is changed the system shuts down and buttons on both hose and regulator have to be pushed to reset, If you've never done that something is amiss.

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If I remember correctly, with the earlier Truma “SecuMotion” regulators, after swapping a gas bottle a button on the regulator itself and a button on the related special Truma gas-hose needed to be pressed to allow gas to flow past the regulator.

 

However, with the current crop of Truma “CS” (Crash Sensor) regulators, after swapping a gas bottle only the button on the special Truma gas-hose should normally need to be pressed to allow gas to reach the regulator.

 

There is a green reset buttonn on a “CS” regulator, but this should only need pressing if the regulator’s crash sensor has been triggered.

 

https://www.truma.com/int/en/products/truma-caravan-rv-gas-fittings/truma-monocontrol-cs.html

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