Oil tank - Turning off supply at tank

Just wondering, can I turn of the oil at the tank...there is a red coloured lever showing on and off.......and if I do, would it cause an airlock, should I want to turn on the ch again, hopefully, not until the end of the summer, of course, having turned the lever to on again, prior to firing up.

Thanks

Re: Oil tank - Turning of supply at tank

No reason you can't do this. But why would you want to??

If you forget then turn on your boiler. Yes it will airlock.