WFP dual pump setup questions (single operator)


Hi all!

I recently made some modifications to the pure water delivery system I have installed into the back of my toyota tacoma work truck. Basically all I did was create a board that holds two shurflo pumps which are plumbed and powered into my single operator wfp system. With the use of a few shutoffs i am able to pick which pump draws from the water tank. The reason for this is because i did a large job a few weeks ago and my only pump failed me in the middle of the job. The ida was that this setup would allow me to switch to my other pump and be up running again within a minute or so.

The problem…
The first pump (left) works fine however the second pump (right) is not able to draw the water out of my tank and into itself to push it through the rest of the system

I am not sure if this is a matter of the pump needing to be primed or what. Any help is greatly appreciated!!
Pic of pump board setup below (Inlet from water tank is on the lower left corner of board)

Side note** I see most wfp systems go tank>pump>filters>hose reel>wfp then on the window.
Would there be a noticeable difference on the pump as far as strain/life expectancy if i were to set my system up so the filters and DI tank were all before my tank meaning i would use the garden house pressure to put water through my filters and fill the tank then simply use the pump to transfer pure water from my tank to hose reel?

Thank you in advance!


Also i forgot to add that the inlet on the pumps are only about 15 inches or so above the outlet on my water tank.


I’m no expert by any means, I don’t even have a WFP but what sort of troubleshooting have you done? I guess I understood you to mean these are brand new pumps? Do you know for a fact the pump on the right works at all?


@dustin145 the pump on the right is new. The pump on the left has a new
pressure switch. Before I put the pumps in the truck I hooked up hose water
to the unit and both pumps worked and pumped water. I can turn the pump on
the right side on and it gets power and tries to pull water from the tank
but just can’t do it. The left pump does pull water and work fine tho


I would put check valves before both pumps, so that once you get them both primed, the one running doesn’t ‘suck the prime’ from the unused pump (if that’s what’s possibly happening). Also check all your connections for leaks. If the pump is sucking air, it won’t prime properly.

But tbh, I think you might be over complicating the issue. Pump failures are pretty rare. Have them setup on quick connects if you want, but just have a one pump configuration. Make sure you have the tools needed to swap in your spare. It should be a 5 minute swap if you set it up right.

Also, invest in a cheap PWM controller from Amazon so you can throttle down the pump and reduce power draw and cycling.


@alex_lacey thanks for the suggestions. I have come to the conclusion that
although the pump on the right is new, it is not functioning correctly. The
pump to the left will prime every time and draw water and it’s actually a
little higher up so their is no reason the right pump shouldn’t work just
as well. I realized I could have done a setup with quick connects instead.
I guess this is a little over the top but I liked the look and idea of it…


I would try messing around with the pressure switch a bit and check to make sure everything is tight.

Imo just having a spare pump in the truck is more than enough, only takes 10min to change it out.


I’d like to see an answer to the second question as well just for my curiosity. Basically could the filters go before the tank and use garden hose pressure to push through the filters. I think the garden hose wouldn’t be enough pressure to push through the all the filters filter but that is just from research I’ve done. Anyone with experience know the answer?


@dustin145 as far as the second question I can say that when my pump died
originally on a big job I bypassed the pump and water tank and just used
the buildings garden hose. I believe garden hose pressure is around 90 psi
in my area. I was able to push thru all filters and up 5 stories to a
single wfp and clean. My only thoughts with filters prior to the tank are
if you dump the tank for weight purposes you are wasting pure water. Also I
will be running a pressure washer off of my tank in the future so it would
be wasteful to run pure water through that. I guess I could try it both
ways with a pressure gauge to see if the pump works noticeably harder when
pushing thru sediment, carbon and DI opposed to just sending it to the


with just the hose?! wow. so why do you need a pump


multiple poles I’m guessing


May 30

multiple poles I’m guessing
Yes 5 stories however the building pressure seemed really high, possibly
more than 90psi. I only run a single wfp at the moment however I like using
a pump so I know I am always covered. When we did the second large building
the water pressure was very weak and would not run a wfp at ground level.
Some guys just use customers tap for residential and that’s great but I
like to be self sufficient in case the customer is on a well or has low
pressure. The only thing I like to ask of my customers is for a referral or
google review if they are happy with the service. Most ppl are nice and
don’t care I just don’t like asking the customer to use this that and the
other thing. No offense to anyone using the customers tap or a garden hose
system, If it works for you keep on keepin on!

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that’s good info. How big of a tank do you run to do a whole house? 1 story 2 story? You just haul your water over there from home? Last question promise:relaxed:


@dustin145 No worries! I have a 100 gallon tank limited down to around 75
gallons with a Hudson float valve. I fill up in the morning and could do 2
or so houses and a handful of stores. My pump is 1.4 gallons a minute. I
would say safely a gallon a window (double hung) or less. Casements would
be less. A 30 window home would be around 25-30 gallons tops and that’s
with excessive rinsing. Could always fill up at customers house but never
really had to.




No problem if you have any other questions let me know and I’ll try my best
to help.


You have done a great job and the plumbing is awesome. But the pumps will not work best in this configuration. The best set up is to fill your tank with pure water. Then have each pump independent and I would highly recommend get a pump control for each pump. This will extend the life of the pump and the battery by controlling the amps caused by back pressure.
I am posting a picture here another system with 2 pumps Each pump can run a pole up to 75 ft high.


Thanks. I actually do have it hooked up to a variatream pump controller,
when I flip the switch the controller powers the other pump. So If I were
to switch the filters around to be in between the fill inlet and the tank
you’re saying everything should work fine? I guess that makes more sense
because you wouldn’t be able to run two wfp’s if the pumps were pulling
hard water from the tank that still needed to be filtered.


Yes as long as each pump draws pure water from the tank on its own.


Can you show a picture of inside the box? does it have ventilation? details on diy?

Thanks for your time