Megaflo hot water tank airgap question

[tom foster]

Our Megaflo hot water tank has recently started dripping quite a bit of water into the outlet dish thingy when heating hot water. I saw the label on the side of the tank which instructs you how to "regenerate the airgap". I tried following these instructions, but it seemed to only gurgle for a few seconds before water stopped coming out of the hot water tap. I saw by searching here that this should take a few minutes...

I was wondering whether it is necessary to actually open the valve (this would require an allen key) or do you just hold open the bit on the side of the valve, which is what I've tried doing, to no avail?

Sorry for the non-technical terms!

 

[gas4you]

Don't know which valve you are referring to with an allan key?

They just the standard knurled knob to turn

 

[gremlin16]

Don't know which valve you are referring to with an allan key?

I think the valve with allen key is a combination valve that houses, line strainer, p/reducer ect.