3/16 or 5/16 with Shurflo

[craigwade2005]

After reading about 100 different threads on the topic I'm stuck if I should run 3/16 or 5/16 laterals with my shurflo pump. It appears that the 3/16 is better for the diaphragm pumps where the 5/16 works better on high vacuum. My runs are short and flat. 75-100 feet with 10 - 15 taps on each run with 4 runs total planned. Thanks for any input.

[Ultimatetreehugger]

Short and flat? You will be much happier with 5/16. I have a piece of road side trees that has short flat runs and a shurflo and I kick myself for not using 5/16.

[mainebackswoodssyrup]

Craig, definitely go 5/16” with your Shurflio on flat ground.

[Biz]

I will go the other way, I think you will get good results using the 3/16 tubing. It is a more forgiving of droops and sags which will can cause surging at the pump. I'm sure a well set up 5/16 tubing will work fine but it is tough to maintain a constant downward pitch in your case. I have a line of 40 taps on about 600' of 3/16, mostly flat, some taps below pump level and a few with 5-6' of drop, and last week it was pulling a steady 19-20" of vacuum at the end of the line all week with good flow. 25" on the Shurflo, 80 taps total. The other line with more pitch, 30 taps, had 25" at the end. Photo at the end of the flat line.

Dave

21091

[Super Sapper]

I will also go with 3/16. The 5/16 will give the best result if everything is pitched right with no sags and no more than 5 taps per lateral no longer than 100 ft. Any sags or more taps per lateral and 3/16 will be better even with sags.

[Wanabe1972]

Ive tried it both ways on some seasonal lines and found 3/16 laterals with 5/16 drops is the best way to go for me. Ive also found if you get 20 or 30 taps on that pump with 3/16 you will keep the pump wet and wont need a recirculation line. I also have 2 8 to 10 foot lifts over driveways that work perfectly.