Sap Lifting Tank doesn't reset

[DucFight]

Just put in a sap lifting tank with a manifold mounted on top with a few lines coming into it. It lifts the sap perfect, only problem is when all the sap is gone, the float doesn't seem to be heavy enough to overcome the pull of the vacuum and drop back down. This results in the little intake valve remaining open. If I push down on the top of the air inlet, the float drops and separates the stopper from the manifold connection allowing the sap into the lifting tank again and the air leak stops. Any suggestions?

[DucFight]

thanks for the suggestions, I extended the float out and considered adding weight but didn't know if there was something I was missing. I will check out the possibility of reducing the size of the fitting. Sounds like I am in for a day of trial and error.

[lpakiz]

Ducfight,
When I read your first post, I misinterpreted the problem and wrote a response that did not fit your issue. I then wrote the second, correct response. In trying to delete the first post, I deleted the second one by mistake. I also finally managed to delete the first errant post. So, that's why both of my posts are MIA. If you need more help, repost here and I'll try again. Sorry.

[DucFight]

Ipakiz,
we messed around with it a little today without much success. The float is threaded all the way out, the inlet the float closes against is one inch, we messed around with screwing it in/ out to get the best alignment. We have 25.5 inches of vacuum on the lines past the manifold. Is this more vacuum than the weight of the float can overcome? I don't know. We have the lifting tank about 200 feet from our 1.5 inch wet and dry line. The manifold/ booster tank is connected to our dry line via a one inch dry line. The lifting tank has a 3/4 inch pipe going up just shy of 20 ft and then is connected back to our 1.5 inch wet line via a 1 inch line. Where it ties in to the wet mainline we use a T and a whip connection to the dry line. Any suggestions. Looks like we could get sap the next couple days. Hate to watch it run on the ground and we still have 900 buckets to put out so I can't just hang out at the lifter all day babysitting it.

[lpakiz]

Ducfight,,
Yes, I think you have a bit more vac than the unit can use. Try adding some weight to the float, temporarily. Perhaps tape a couple nuts or a 1/2 inch bolt to the float? If that helps, could you drill a hole in the float and add some BBs? Then silicone it shut? Don't worry about ruining the float. They are available in your big-box builder store, very cheap.
The other suggestion is to reduce the inside diameter of the inlet fitting. This will reduce the area that the vacuum is "grabbing" and will reduce the total force (weight) needed to break the pad loose from the fitting. If you know someone with a lathe, he could make a thin-wall insert that you could glue into the ID of your existing fitting.

Is your fitting a dark grey, schedule 80 PVC elbow or nipple? The schedule 80 has a smaller ID than schedule 40, so if this fitting got switched, that could be the problem. A smaller ID will help.....

[DucFight]

Well that is discouraging. Work hard to keep the vacuum levels up only to find it may be too much for this lifter. HMMM What to do, Anyone lift sap close to 20 ft in one shot with a ladder. 2 pipe or spider?

Thanks for the suggestions Ipakiz. I may look into reducing the diameter of the inlet fitting. Even if the fitting size is reduced, will this make much difference? There will still be the same vacuum force on it.

[Brian Ryther]

[QUOTE=DucFight;245010]Well that is discouraging. Work hard to keep the vacuum levels up only to find it may be too much for this lifter. HMMM What to do, Anyone lift sap close to 20 ft in one shot with a ladder. 2 pipe or spider?
I have a hand full of sap ladders that are close to 20'. both spider and 2 pipe systems. Both work just fine. Install, tap and walk away. Check your sap totals at the end of the season and you will see that they worked.

[DucFight]

Thanks Brian.

[GeneralStark]

That is strange. I just set up a sap lifter and it has been working fine with 27.5". It sounds like there is better air flow on the manifold side of the lifter than on the sap outlet side (3/4"). Once the sap is lifted out the 3/4" line and drains the tank, air flow through that line should help reduce vac. pressure on the stopper and allow it to fall.

[DucFight]

General,
Not sure how you set yours up but we have a dry line running into the manifold from our 1.5 inch dry line so we always have maximum vacuum (for us) on the manifold and mainlines going to the taps. So when the lifter dumps, air is introduced into the lifting tank reducing the vacuum level in the tank allowing the sap to escape but the vacuum level is still the same in the manifold which is what is holding the stopper up which continues to allow air into the lifting tank so the vacuum level in the lifting tank is not equal to the manifold side, therefore the stopper wants to stay "sucked up" to the manifold side. This is where the weight of the float comes in and the force which it is able to apply to overcome the vacuum from above holding the stopper up. With force being equal to PSI x Area, a smaller fitting would require less force to overcome the vacuum. I wonder if maybe the float on your lifter is heavier. Looks like tomorrow will be another day of trial and error.

I appreciate everyone's help on this.

[nymapleguy607]

Ducfight,
I saw one of the lifts operating last year at CDL's open house and they were just using a single line to run the lifter.

[DucFight]

Maybe that is my problem. I'll give them a call and see what they say.

Thanks

[inthewoods]

i had similar problems last yr, futzed with it every day until i epoxyed a .5 inch nut to end of float ball. im running about 26+ inchs. when i asked salesman for help he told me to create a vac leak (really???) i could of just kicked him in the a$$. the lifter seemed to work better at lower hg but that was not acceptable for me, thats when i put nut on.

[GeneralStark]

The problem I am now having with mine is not that it won't reset after discharging, but that the float is not able to lift the plunger and push up the cap to create the leak. It seems as though the high vac. is keeping the cap sealed tight. Fortunately the lift is near the sugarhouse so I can check it when I am around but I would like to be able to leave it and not worry about it.

[lpakiz]

General stark,
OK, this the the problem I mistakenly replied to at the top of this thread, which I subsequently deleted when I realized I misunderstood the problem.
On this issue, the vent plunger is held down tight by vacuum while the tank fills. The float is supposed to be buoyant enough to lift this vent plunger off its seated position when the tank is almost full. What we found in our homemade one is that the diameter of the O ring groove under this vent plunger is CRITICAL. We found that a reduction in diameter of .020-.030 makes a HUGE difference. It gives the vacuum a little less area to "grab" that plunger and hold it down. Our originals would work fine up to about 22, but at 26, the float couldn't lift it off its seat.
First, try extending the float to as long as you can get it. That gives it more mechanical leverage. Seems like this should help, but in our case, it didn't. We ended up making a new top vent cap with the reduction in diameter as stated above. We used the same O ring, it just doesn't fit quite as tight in the groove. Works perfectly.
It seems that both of these issues might be resolved if the float was a bit bigger (more buoyant) and heavier (to help pull it down to reset)

[GeneralStark]

Thanks for the advice. It seems that this device was not intended for high vac. I am going to speak to the guy I got it from as I believe he was running 26" with it. I am running 26.5-27.5 at this point. Could be higher but I need to incorporate a leak at the releaser to keep the pump from cavitating.

[lpakiz]

I think it can be made to work with higher vacuum. When you spend the money you did, none of this should be necessary.
General stark, a couple posts back, you mentioned that it was working fine @ high vac.
Out of curiosity, I wonder how many folks are running one of these at vacuum over 26.5 or so and don't have ANY problems. Now I mean 26.5 at the lifter tank back in the woods, not 26.5 at the releaser.

[GeneralStark]

The issue has been intermittent. I should say that I did get it used so I didn't pay retail for it. This morning it has been working fine and the sap is flowing pretty well. I did lube the plunger this morning with some glycerine so perhaps that helped. Going to keep an eye on it today. Next time I turn the vac. off I will make sure the bulb is fully extended.

[DucFight]

So we spent a few hours messing around with the lifter today trying different things. First thing I tried was adding weight to the float. NO GO. then I took out the adapter that the float closes up against and put in a one inch plug and drilled a 3/8 inch hole in it to reduce the surface area that is pulling up holding the float closed. NO GO but required less manual force to get it to drop. So then I added a loop from the wet line into the dry line thinking that this would allow some of the air being sucked up to go into the dry line and then back down to the manifold to reduce the vacuum in the manifold which is pulling up and holding the float closed. This works!! Now the problem I am having is the float is overloaded with weight and won't quite trip the air intake. I figure this is an easy fix. Tomorrow I will be putting some Foam on the float rod to assist the float. I Hope this works. We are running about 25- 25.5 inches of vacuum at the lifter.

Thanks for everyones suggestions

[GeneralStark]

I fully extended the float and now it seems to be working perfectly. Ran all day yesterday without me having to trip it. Had a minor issue with ice blocking the drain and keeping it open creating a leak, but thawed it out with a heat lamp. I have the lifter and manifold in a box so I can heat it with the lamp as once the season really gets going and I leave the vac. on 24/7, I can hopefully avoid any freezing issues.

[DucFight]

I added a piece of 1.5 inch foam on the float rod between the float ball and where the rod screws onto the stopper mechanism to help offset my weight. It worked flawless the other day. Whether what I've done to make this thing work is right or wrong I don't know, what I do know is I now have the sap from an additional 200 taps making it to the sugar house that I wouldn't otherwise. :D
Thanks for everyone's help,