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Pump priming problem

cw4Bray ยท 2024-12-11 23:22

I'd like to water my garden from a nearby river with a 2" pump. I want to keep the pump at the top of the bank, because the bank is very steep, 10 vertical feet . I don't have a foot valve for priming. I've got a 1.5" venturi which I'm pondering glueing to a two inch pump. I know the simplest and surest way would be to place the pump on a raft down low in the water and maybe that's the correct answer. To access the water, I could build some steps into the bank. I've also got a cheap chinese diaphragm pump that I could use for priming but it struggles lifting 10' as the plastic handle bends under the strain of the vacuum. Will it work ? How much draft lift can I expect from a 1.5" venturi ?

Replies26
  1. #1Joe H2024-12-12 00:40

    Permanent pipe up from river with check valve at the bottom end ? Water well type ck valve

  2. #2Willie B2024-12-12 08:04

    Use a wet vac for priming.

  3. #3cw4Bray2024-12-12 13:42

    Thanks !! The Foot valve makes the most sense but I'm trying to get by without it. I tried using a Shop Vac but it struggles to lift eight feet even with a leak proof tight seal.

  4. #4cw4Bray2024-12-12 14:22

    The first picture might need another vavle or cap at the top of the tall vertical priming tube. This is to vent the drafted air From the venturi, but then once primed it needs to be closed to the pump discharge. The second picture would be a configuration using a one inch hand operated diaphragm pump. In this configuration I'd put the pump down close to the water. What do you think ?

  5. #5reganj2024-12-12 21:58

    My .02,, Pump is to pump water to water storage tank close to garden. Big enough water storage tank and you will only have to run pump every once in a while. Pump is not made to suck water up 10 foot. Place pump as close to water as is safely possible. Enjoy.

  6. #6SLK0012024-12-12 23:35

    You really need a foot valve for your setup, especially with it so far above the river. Why are you so hesitant to install one?

  7. #7Willie B2024-12-13 07:07

    Without a check valve at the bottom it won't be simple. Having the intake in the stream vertical open on bottom might help. I've done it easily with a shop vac even higher. Water weighs about .0335 LBS per cubic inch. There is no such thing as a vacuum, only the absence of pressure. If a vacuum cleaner were the most powerful imaginable, atmospheric pressure could theoretically push water up 36 feet in elevation to the pump. Vacuum must T into the outflow above the pump.

  8. #8Vetech632024-12-13 07:40

    When I have a pump priming problem, I find that an extra cup of coffee and some good morning stretches can get me there. It helps if the wife is wearing som....................oh wait........

  9. #9cw4Bray2024-12-13 12:47

    I love my stainless steel coffee mug. It was a Christmas gift from a son inlaw. It's got double wall vacuum insulation. It changes the taste of coffee as it slowly cools.

  10. #10cw4Bray2024-12-13 13:54

    The venturi seems like magic. Any experience you could share with drafting venturi's would be greatly appreciated. What size have you used ? Are you drafting from more than a flatbed truck ? I'd like to run the open suction line unrestricted open near the river surface on a float. Maybe I'm looking in the wrong home improvement store, the foot valves I've seen at the hardware store max out at 1.5" for a sump pump check valve or 2" for a sewage backflow valve. I'm trying to reduce resistance and cavitation, especially on the suction side. Overcoming the spring pressure is more resistance. Anything less than 2" is an impedance for my application. If HEF says foot valve is needed, I could make one on my 3D printer. Then market the; "6 inch fat Bob foot valve" ?

  11. #11SLK0012024-12-13 14:29

    You can pick up a 2" PVC foot valve for $15 on Amazon.

  12. #12cw4Bray2024-12-13 14:58

    Interesting online shopping. Thanks SLK, That 2" foot valve is about the equivlent of 1" valve - once it goes through the curve of the valve frame. So $15. isn't going to do it. A 8 inch valve is $500. ouch ! I can use city water for three summer months for less than that, if I amortize over the remainder of my already long life, it doesn't pencil out.

  13. #13SLK0012024-12-13 17:07

    Okay, so what are you really watering? Is your garden a 50' by 50' plot, or is it 40 acres? Your intake is still only a 2" pipe, isn't it? Even with an 8" foot valve, your pipe is still 2" in diameter. Your pump is capable of pumping greater than 100 GPM.

  14. #14cw4Bray2024-12-13 18:27

    It is a 50' X 50' plot with every type of produce you can think of. Been watering from a 100 year old hand dug well but it goes dry after July. The city water we drink from just doubled the rate$ so it makes sense to improve the water source. SLK, I'm from the (tool time) Tim Taylor school of more power. When I get tasked by the "war department" to water tomato's or potato's I don't want to stand around "gently sprinkling" for one hour with a 150' long 1/2" garden hose from a one KW electric pump. I think I can get the job done faster with a 1.5" hose from a three KW Gasoline pump. Also I'd like to be able to drill a new well with the 1.5" line that I need lots of water to drill with. I've also been thinking of digging instead of drilling. I've got several short sections of 18" pipe that I could use for a well. I've got a Bobcat 418 that I'd copy what Spud pulled off. What a cool trick that was ! The 2" pump is really old and weak, it may have been 200 GPM when new, but not when pushing 500' of 1.5" line

  15. #15SLK0012024-12-13 20:09

    Have you seen the stream from a 100+ GPM water hose? Think "flash flood". It will scour everything in its path. Instead of watering your garden, you'll be digging up everything and pushing it away from you into one giant heap. You'll need some way to slow the flow down, like installing an above the surface sprinkler system. In an application like this, bigger is not better.

  16. #16cw4Bray2024-12-13 20:29

    Sounds great for drilling a 3" diameter PVC well !

  17. #17terex herder2024-12-16 22:33

    check out exhaust primers. From what you describe they will work.

  18. #18Willie B2024-12-17 07:48

    Fire trucks used to have exhaust primers. When I was a teenager our small volunteer fire company still had one old truck with one. It was difficult to pull prime. Two spots where we put the truck on a bridge & lifted 15 or more feet in elevation to get prime, it was difficult at best. My in laws had a system much like what we are describing. They did have 1" suction pipe with a cone shaped screen/foot valve. It needed priming once a year. A funnel was used to get water into a port on top of the pump. Fill it up, screw the plug in, turn it on, good for the summer.

  19. #19cw4Bray2024-12-17 10:47

    This pump had been used to bail out flooded basements. It had a 1" reducer on the 2" intake port, which seems almost criminal on the suction side. I'd like to get 30 PSI at idle or 1000 RPM, I'll experiment to see if that's possible.. On a different note, This primer pump, (for my 2" gas powered) was only $10. but struggles to lift 8' - 10'... However, it does a good job of pumping sewage from a boat.

  20. #20cw4Bray2024-12-17 18:02

    Found this; How Much Vacuum Can A Venturi Pull? - ToolingIdeas Venturi pumps are a crucial component in various industrial and scientific applications, offering a reliable and efficient means of creating vacuum or toolingideas.com I'll need to add gauges on suction / discharge and dig out the high school math book to get the draft answer.

  21. #21Welder Dave2024-12-18 04:01

    Check how many feet of head the current pump is good for. Those pumps are often used for fertilizer or other chemicals and may not draw as much head as a std. pump. I'd ditch the PVC and use std. Suction hose with a foot valve and lay flat discharge hose would be the least expensive. To prime just fill the pump through the discharge or the priming plug after the discharge hose is connected. I think most std. pumps have a max. head of 30 feet. You need a simple foot valve if you're pumping straight up.

  22. #22cw4Bray2024-12-18 11:28

    Thanks Dave, I just checked and found out that pump is "no longer available". (I wish I hadn't looked it up) No sucking rocks with it, if I want to keep it. Nice to know; The pump's a 140 GPM 50 PSI, 110' head 25' suction Lift. Then I looked up the specs. for the venturi, to make sure the venturi will be able to operate my system with the required operating pressure and flow. 27.7 GPH suction with 42 GPM going through the injector with 50 PSI on the inlet and 39 PSI on the outlet. To make sure the venturi will be able to operate on your system, you need to know your operating pressure and flow. So it should take around five minutes to prime 20' of suction hose.

  23. #23Welder Dave2024-12-18 23:04

    Pressure also relates to how much total head. You can get higher pressure pumps often referred to as fire pumps but they aren't true fire pumps. Fire pumps are generally 2 to 4 stages and very pricey. Higher pressure pumps have less GPM's.

  24. #24cw4Bray2024-12-18 23:57

    Thanks Dave, I knew that Honda offers a choice of different impellers for their pumps. The pricey ones are for the government. "We're here to help you".

  25. #25Welder Dave2024-12-19 01:43

    Honda has an 1 1/2" pressure pump. I don't think they have special gov't. pumps or impellors though. I've also seem fire pump kits that come with a cart to move them around. They have suction and fire hose type discharge hose and I think a foot valve. You want a good screen on the suction hose unless you have a trash pump. A semi-trash pump will handle some debris but the higher pressure pumps are usually for clean water and need a finer suction screen.

  26. #26cw4Bray2024-12-19 09:41

    A few years back, the military was using a P250 Kawasaki jet ski pump. That would put my Briggs & Straton to shame. I can only imagine what they have now.