Recirculation Line for Shurflo Questions

[SeanD]

I'm planning to add a recirculation line to my Shurflo. What happens when the tank is empty at the start of the day? Won't the recirculation line be pulling air and loose vac on the rest of the system? I think I missed a key detail in the threads on this.

[blurr95]

When I pumped my tank out, it was up hill to where I was loading my tractor, I would let the sap in the line run back into the tankso there would be a little for recirc. Or you can add a bit of water, I did this when it warmed up more.

Jason

[BAP]

I leave 1-2 gallons in the tank so that the line is covered and has sap to recirculate.

[SeanD]

Ok, I'll have to make sure the end stays down securely to the bottom corner. Maybe I'll zip tie it to a length of pvc?

Thanks,
Sean

[mike103]

I use a 3 ounce fishing sinker tied on the end of tube. Lead free of course.

[SeanD]

Same topic, new question:

I've read about setups where people simply have a length of 5/16 for their recirculation line and read about others where the recirculation line is controlled with a needle valve. I don't mind making the extra effort and plumbing with the valve, but are the gains noticeable enough to justify the extra effort?

If restricting the flow in the recirculation line is critical, what about just putting a clamp on the 5/16"? Is the precision of a needle valve that significant?

[Waynehere]

I did a recirc line last year and had a record year for syrup production. I got a total of .52 gal/tap. I had to do the math several times. I tried a hose clamp from the auto store and it didn't work very well. I am going to try maybe some pex valves this year. You just want to keep the pump wet, not full flow of sap from the tank. I used some stainless nuts with a scrap tee fitting on the end, that I had cut out of my setup for some reason or another.

Now with that in place, I had to rethink my temp controllers because with leaving the sap in the tank, things froze up when the pumps stopped circulating, so I had to go and manually turn them on and off all the time, as well as drain the tank and recirc line, but the increase in sap production was worth it. Of course I did try some of the CV spouts on 100 of the 240 taps too, so that was probably a factor as well.

[BAP]

I use a recirculating line on my Shurflo 4008 pump. First year I used a ball valve on the line and it worked OK, but hard to get it set to the point where there was a steady flow through the pump but not too much that reduced sap flow from the mainline.

[Waynehere]

I use a recirculating line on my Shurflo 4008 pump. First year I used a ball valve on the line and it worked OK, but hard to get it set to the point where there was a steady flow through the pump but not too much that reduced sap flow from the mainline.

Interesting. So do you use the needle valves now? May have just saved me some time and money... :)

[BAP]

Yes I do use a needle valve.

[SmellsLikeSyrupNH]

Anyone have a picture of this?

If im understanding it properly, should I just run a T in front of my strainer with my main line coming from my sap lines and another line just into my collection tank, where I should leave a few gallons of sap or water, so that it just has something to flow through the pump? If im reading the tech sheet correctly, it looks like the pump will draw 6 amps if only .5gph flows through, but only 2 amps if 3gpm is flowing. Im setting up 3 separate pump systems and I want to make sure im doing it right.

Thanks again!

[Biz]

On the Shurflo 4008 pumps you will see less than 2 amps current draw, usually between 1-1.5 amps, flow or no flow.

For recirculation line, on my test setups I use a 1/8" barb with piece of 2.5mm silicone tubing with no needle valve and I see 20+ inches (no sap line, just the recirc). So it doesn't rob vacuum like a 3/16 recirc line would. I often just use a short piece of the small tubing then use 3/16" if it needs to run further.

Adding a 1/4" ball valve in series with the tubing to restrict flow a little more will get you about another 5" of vacuum. If anybody is coming to the Brattleboro maple conference this coming weekend, I will have my demo unit going, stop by and check it out.

Dave

[SmellsLikeSyrupNH]

Thanks Dave!!

I'll give that a shot.


On the Shurflo 4008 pumps you will see less than 2 amps current draw, usually between 1-1.5 amps, flow or no flow.

For recirculation line, on my test setups I use a 1/8" barb with piece of 2.5mm silicone tubing with no needle valve and I see 20+ inches (no sap line, just the recirc). So it doesn't rob vacuum like a 3/16 recirc line would. I often just use a short piece of the small tubing then use 3/16" if it needs to run further.

Adding a 1/4" ball valve in series with the tubing to restrict flow a little more will get you about another 5" of vacuum. If anybody is coming to the Brattleboro maple conference this coming weekend, I will have my demo unit going, stop by and check it out.

Dave

[steve J]

I am experimenting with 16 taps on 3/16 line running to a shurflo pump. just before it gets to the tote the line converts to 5/16 and that connect to pump. I plan to run 5/16 to discharge to the holding tank. If I wanted to add a recirculating line would it work if I put a T in the 5/16 prior to the tote and neck that down to a 3/16 that runs to holding tank? I had not originally planed on this when setting up my tote. And I take it that it will not work without it?

[SmellsLikeSyrupNH]

That should work, like Biz says up above having too much coming into that recirculation line may limit your vacuum but it will still work. I have 3 lines coming into my pump, attached to a 4 port manifold. The manifold has 4 valves and the 4th one i use as my recirculation line. I close the valve a bit so that it can at least have something to pull through the pump when it turns on. I have not put gauges on my lines to see how much I am getting, but one of these days I will. I have them just been too busy dealing with other things to go out and install them.

[steve J]

In terms of a needle valve I saw Home depot had 1/4 OD valves. I am not sure of of diameter of 3/16 line as I am at home and not up where I sugar. But I suspect that might fit inside of a 1/4 valve? Also when the sap is running well would you dial the valve down fairly tight since you don't really need the recirculation?

[Urban Sugarmaker]

I have 1/4" compression by 3/8" MIP threaded needle valve from Home Depot. I bought a 3/8" female thread (FPT) by 5/16" barb to go on thread end, and used 1/4" tubing from the same section at Home Depot where the needle valves are on the compression end. I believe the tubing is generally used for water supply to refrigerators for drinking water.

So there's a saddle from the manifold at the pump, a piece of 5/16" maple tubing, the valve, then the 1/4" tubing to the tank. I tied it on to a stainless steel tri-clamp hardware piece I had around. Works great. I open the valve one turn only.

[maple flats]

Once you get the needle valve adjusted to give you good vacuum, do not change the setting.

[steve J]

I could not duplicate what you bought at home depot. But I did find a 1/4" ball valve and a couple 3/16 scree in barbs. So I think that will solve the problem I hope.

[Cjadamec]

You will have a very hard time using a ball valve to control small amounts of flow like that.

If you can wait a day or two Amazon has brass needle valves for 7.99. (https://www.amazon.com/gp/product/B008E33JHQ/ref=ox_sc_act_title_3?smid=ATVPDKIKX0DER&psc=1)