Vacuum Diminished?

[Bullet]

Every year in the past my vacuum had consistently been 25" to 28". I store all my equipment in a heated basement in the off season. This year my vacuum has been 13" to 15" with a heart beat in the gauge, unlike the past. I've checked all the fittings and re-tephloned and plumbers goop, all to no avail. Checked all my lines (tired of walking), nothing makes sense. My last thought is the SS motorized valve may not closing as it should and ball may not be making a seal upon activation. I'm thinking of switching out SS valve at a considerable expense. It's my last option and its a pia to do. Has anyone had one of their SS motorized valves fail to make a seal? THANKS

[Ultimatetreehugger]

Check your gauge, that was my Achilles heel for 2 years without knowing it until I replaced it for no reason and my vacuum jumped. Put the old one back in in another quieter location and could here it lightly squealing.

[Bullet]

Thanks Ultimatetreehugger, however upon checking the drops, they are not emptying nearly as well as past years. Sap is not running as fast, nor is the rate of collection in my barrels as it was. I know this is subjective but all the signs and symptoms indicate that the vacuum is not pulling and seems to be consistent with what the vacuum gauge is telling me. Love your golden.

[Super Sapper]

I assume that your valve is threaded. If so, put a plug in the discharge side to see if it is not seating properly.

[BAP]

I assume that your valve is threaded. If so, put a plug in the discharge side to see if it is not seating properly.
I assume that the vacuum pump is the Shurflo that’s in your signature? Do you have a suction screen on it? If so, I found on mine that the bowl holding the screen has to be screwed on really tight or it loses vacuum. Also, instead of replacing the valve, can you just stick a plug into it?

[maple flats]

Too many variables, could be the pump diaphragm, a tiny leak some where, a bad gauge or several other things. because the sap is moving slower I'd change the diaphragm first, it's easy. In fact, while I only use a diaphragm pump to push fresh water thru my tankless water heater (or for cold water too) I keep a spare diaphragm in stock as well as a spare pump. Just use this saying, "2 is 1 and 1 is none"!
Good luck.

[Bullet]

Thanks all. I've changed the shurflo diaphragm pump, I've changed the screen filter and tightened down the housing, today I swapped out the SS ball valve, I've tightened all the fittings. I'm gonna check my lines again, however a leak in the lines generally shows racing bubbles, which I've had in the past and is an easy diagnosis. I guess I'm gonna have to live with the low vacuum this year and take everything apart in the off season. Don't think its the vacuum gauge as everything else I've witnessed is consistent with low vacuum as compared to previous years. By the way I have a MountainMaple Vacuum system, which worked great in past years. Thanks again for everyone's contribution.

[madmaples]

are you recirculating any sap? it made a huge difference for me, it took my 10-15in -> 25-27in

[BAP]

Thanks all. I've changed the shurflo diaphragm pump, I've changed the screen filter and tightened down the housing, today I swapped out the SS ball valve, I've tightened all the fittings. I'm gonna check my lines again, however a leak in the lines generally shows racing bubbles, which I've had in the past and is an easy diagnosis. I guess I'm gonna have to live with the low vacuum this year and take everything apart in the off season. Don't think its the vacuum gauge as everything else I've witnessed is consistent with low vacuum as compared to previous years. By the way I have a MountainMaple Vacuum system, which worked great in past years. Thanks again for everyone's contribution.
Don’t assume that just because you can’t see the “Racing Bubbles “ that you don’t have leaks in the lines. If that line isn’t producing much sap because it has lower vacuum you may not get enough sap in it to see the fast moving bubbles.