Switching from buckets to Shurflo on solar vacuum help

[mudr]

how do folks deal with freezing if the diaphragm pump is located below the tank and it has to pump upwards? doesn't the pump out line freeze solid?

[Biz]

It will freeze up. You need to drain the line after the pump shuts off. One way to do this is place a tee in the pump outlet line, and add a ball valve to drain the line when pump shuts off. If you are using a controller for the pump, for the valve you can use a normally-open motorized ball valve wired in parallel with the pump. When the pump turns on, valve energizes and closes. When pump turns off, valve opens and drains line. I have set up systems like this with the S3 controllers as well.

Dave

[Openwater]

Ok, I didn't think of the pump being lower than the collection tank with freezing. I assume if I put the pump higher than the tank and the outflow just drops into the tank, I shouldn't have problem, right?
Do you have a diagram showing how to wire the motorized ball valve into the temp controller? In case I can't get my pump high enough to drop outflow into collection tank; remember, this is in perfectly flat woods. I assume its safer to have sap freezing in the in-flow/lateral line as opposed to the out-flow. Obviously, raising the pump too high is going to cause sap to collect in the lateral leading into the pump manifold.

[Openwater]

I got everything I need for the solar vacuum set-up except the battery. I got a MPPT solar controller which says it can handle sealed/flooded/gel/AGM and lithium batteries. I know you said a good lead acid deep cycle marine battery can run the 4008 pump for 35 hrs without recharging, but would one of the other more-expensive type batteries work or give better performance/longevity during stretches of cloudy days?

[Biz]

The pump run time is based on battery amp-hours. A battery with higher amp-hour rating will run the pump longer than one with a lower amp-hour rating. I would be interested in how well a lithium battery performs compared to a lead acid. I bet for equivalent run time, the battery would cost 3-4 times (or more) what a marine battery costs. They are much lighter and should last longer.

Dave

[highlandcattle]

We used Trojan lead batteries on our off grid farm. Lasted 10 yrs.

[Openwater]

I got my pump plumbing and electronics assembles in a tote/bin and solar panels mounted on an adjustable rack/stand.
Now, since this is my first attempt at a tubing system on mech vacuum, I got some questions about running the laterals, installing drops, etc.
I plan on pre-assembling the drops w/spout on one end and T on the other, probably making them 32-36". If a drop is too long when tapping, is it ok for it to form a loop/trap below the 5/16 lateral? I plan on the pump running as long as there's sap flowing (temp controller set to turn on pump above 33-34 degrees F).
Will there ever be frozen sap in the drops or laterals if the pump is running as long as sap is flowing? ie, the pump doesn't shut off until it gets down to 32 F.
Thanks for the input.

[Biz]

I set up controllers to turn off at 29 or 30 degrees F. I have found that sap is usually running in lines for a little while below freezing, so pump is kept running until sap stops flowing.

Dave

[Openwater]

Sap still flowing at under 32 F? I didn't know that could happen. I guess I still have alot to learn about maple tree physiology.
The only other conundrum I'm facing is this issue of the recirc line on the Shurflo. I've got my (2) 5/16 laterals (less than 300' each, 10 taps each) going into a 3 point star fitting on the pump intake, so I do have an extra 5/16 point on the star to plug in another line for the recirc, but, won't this lead to residual recirculated sap freezing in the pump once it shuts off at 29-30 F? Approx how much vacuum am I giving up by not having the recirc line?

[Biz]

My theory on the sap flow is that the tree and sap in the tree takes a little while to freeze after air temp drops below freezing, so sap continues to flow a little longer. I have seen lines still running in the early evening when air temp has dropped to a little below freezing, while nearby buckets where sap is exposed to air are stopped and frozen.

You may lose a little vacuum from the recirculation line. The vacuum loss can be minimized by keeping flow just low enough to keep the diaphragm wetted to draw sufficient vacuum. Your conundrum is a valid one, the recirculation line will likely not freeze so the pump will always have sap in it. You could turn off the recirculation once sap has started flowing well, if that is possible, since it is mostly effective after pump first turns on. My systems have a sap purge function which automatically purges sap from the pump for a few seconds before shutting it down - this allows a recirculation line to be left on. Something similar could be done with ball valves if it is manually turned on/off.

Dave