Fillpoint leaking after filling up with LPG.
In every GAS IT LPG fill point there is a valve that is designed to close when the fill gun is removed. On the very rare occasion the vehicle filling up on the same pump before you didn't have a dust cap or lid on the fillpoint ( its a legal requirement under R67 to have some means of a dust cover ) and they got dirt ( mud, grit etc ) into your fillpoint ( when you filled up ) then this mechanical dirt can be pushed into the fillpoint and hold this non return valve on the fillpoint and also the bottle or tanks 80% shut off valve slightly open which will cause them to let the gas back out. Now as these leaks are usually very small, the excess flow valve in the 80% shut off valve won't see a big enough pressure drop and it will continue to leak out until the bottle or tank is empty.
The first thing you can do if you suspect the fillpoint is leaking, is to reattach the fill gun and try and pump a little more gas in. This will generally push the dirt from the valve in the fillpoint down into the tank or bottle - but this doesn't always work. The benefit of having the fill gun re attached as though you are filling up is this will make the fillpoint fully sealed and will stop the leak - so you can then contact GAS IT or a local LPG installer who can come and help you out.
They will then try and clean out the fillpoint and elbow/valve on the bottle and tank by releasing the pressure of gas to force any debris outward.
To stop this happening in the first place, we recommend you always do a visual check of the fill gun before you put it on your vehicle to make sure its not covered in dirt or mud. You can also buy a filter that screws in the fillpoint before you fill up so that any mechanical dirt is kept away from the valve in the fillpoint and also the 2nd valve in the 80% shut off valve in tank or bottle.
It's GAS IT Part number is GI-0055 and description is 'UK Fillpoint Bayonet and Direct Gas In © Filters'