MKV pump issue

[Philtre]

Hi there. Anyone know why there is small hole in the back of the MKV pump made by Munster Simms Engineering? Discovered this after I changed the diaphragm. It now leaks through this hole! And do I stop it leaking. I suspect I have done something wrong when reassembling.

[GordMay]

Munster Simms Engineering Ltd designs, manufactures and markets, under the product brand name of Whale products.

Whale MkV Pump
Data Sheet ➥ https://defender.com/assets/pdf/whal...5universal.pdf
Installation Guide ➥ https://defender.com/assets/pdf/whal...74_install.pdf

I see no reference to a small hole, on the back of the pump.

[rslifkin]

The hole goes into the chamber on the dry side of the diaphragm, right? If so, I expect it's to equalize air pressure to make pump operation easier (vs building up pressure in that chamber on the up stroke of the pump). If you're getting liquid out of that hole, it's likely due to fluid leaking past the diaphragm somewhere.

[wrwakefield]

I find I have to tighten the large nut in the center more than you think when installing a new diaphragm or it will leak.

Also confirm the two washers are radiused side to the diaphragm.



I have learned to test before reinstalling the pump by plugging the outlet with my hand and gently pumping air- listening and feeling for a leak.

HTH

Cheers, Bill

[Philtre]

Thanks for all your advice. I found the central nut was loose. There's still a little water coming out but I guess the chamber that is usually dry still has some water in it so may take a few strokes before it stops.