Brass Swing Check in Vacuum

[Amber Gold]

I have an electric releaser with a sta-rite submersible pump. The pump discharge line has a short nipple, brass swing check valve, and short length of pipe before the elbow to exit the releaser. The short nipple has a small hole drilled in it to prevent the pump from air locking.

When the liquid level gets above the hole, the sap bubbles like crazy...there's air coming into the releaser...wouldn't have known it otherwise. This means the brass swing check isn't sealing properly and is leaking air. I pulled it out and the sealing surfaces looked fine.

Questions I have are:
The pump has it's own check valve, so why is a second one needed?
If a separate check valve is not needed, then how do you bleed air to prevent the pump from air locking?
If a second check valve is needed, is it OK to use a brass swing check...is it going to seal tight? Mine's been around a while, so maybe it can't seal properly and needs to be replaced??
I've never liked the spring check's because the pump has to pump against the spring to open it. To me, you're making the pump work harder.

Thanks

[wiam]

I have built, I think 3 moisture traps using 1/2 brass swing checks for the drain. None of them sealed when brand new.

[WestfordSugarworks]

i know i'm not answering all your questions, but i'd just replace the brass valve with a plastic one. We run 3 plastic check valves in total and they all don't leak as far as I know. We get them at our hardware store. Maybe your brass valve is not lead free, if so it's another reason to replace

[GeneralStark]

I briefly used a brass swing check on an electric releaser pump out line and then quickly changed to a plastic one as the brass one leaked. You're saying your releaser is set up with the check valve inside the chamber? If so I suggest getting rid of the brass and plumb a plastic one in outside of the chamber.

[Amber Gold]

The pump has a built-in check valve...flapper valve really.

The brass check valve is just above the pump, so yes it's inside the main chamber of the releaser. Not sure why I put it in there, just seemed like as good a spot as any. Curious, why does it matter where the CV is installed? The further the CV is from the pump, the more sap will drain back into the releaser.

I went to both Lowe's and Home Depot and neither had a 1.25" CV. I'll have to grab one from Webb.