12v pump cavitation?

Having a problem with my 12v pump(s) and can’t figure it out. I don’t believe it is due to cavitation but hopefully someone can confirm. After getting the pump set up and primed to apply roof chem, I am able to get my initial application on. But after shutting off the ball valve for whatever reason(re-position on the roof, turn off the flow to wait for the run down, etc.) the pump will not re-start when the valve is opened back up. When I climb down from the roof and check the pump, I find blown fuses. After removing the fuses and wiring directly from pump to battery, the pump will simply not start back up.

I’m using a 12V deep cycle marine battery(Interstate) and a 12V, 5.5gpm, 60psi Everflow pump. I even tried bypassing the relay switch to see if the pump would start back up. Nothing. My inlet line is 1/2" braided poly. The outlet line is 1/2" yellow KuriTek chem line. Please HELP!!

You said you find blown fuses as in this happened often. How many times have you blown a fuse? Me thinks you burned it up just based on the small amount of info.

I’ve blown 3 fuses at different times. I haven’t burned it up because it re-starts the next time, then does the exact same thing…runs initially, then fails to re-start after the initial run time, or after I close off the supply end.

I’m wondering if it has an internal heat safety shutoff? That would explain why it won’t restart immediately after blowing a fuse.

What size wiring did you use? And what rating fuse?

It comes with 14ga I believe, so I match that to wire it to the pump. I have blown a 10amp, 15 amp and 25amp fuse, all in the same day. I don’t know about a heat safety shutoff. There is nothing in the manual about that.

That pump pulls a max of 17 amps, so the 10 and 15 amp fuses were insufficient. 14ga is also insufficient for more than the few inches on the pigtail wires that come on the pump. I would use a minimum of 10 gauge, or even larger if it’s more than a few feet to your battery. Undersized wiring is a fire risk and can cause the pump to overheat.


Pressuretek recommends at least a 30 amp fuse

OK thanks very much infinity. Should I tie into the existing wire or open up the pump and replace it all? Not sure I’m good enough to do that.

30amp fuse with 10ga wire?

Ok, that pump must have termal protection that’s tripping too. Just run a 25 or 30 amp fuse and step up your wire size. I have a Shuflo 5059 and it requires a 25 amp slow blow fuse to deal with the spike. I don’t believe those fuses come in a mini style though.

Yep. 10 gauge copper wire is rated to 30 amps.

OK perfect. Thanks!

OK I’ll take your word on that one. The owner’s manual is maybe 2 pages so I won’t find any details there. I’m pretty sure the largest mini I can find it 25amp. I will use a 30amp and wire in the proper fuse holder using 10ga wire. I’ll let you know how I make out. Thanks a ton for you help!

That explains why I blew a 25 then.

Oriellys, autozone or Napa will have what you need for fuses

I had one of my NT pumps start doing the same thing about 2 months ago. It was blowing the 30 amps too. Exact same thing yours is doing. It now resides in a waste dump somewhere. I have around 7-8 12 v pumps at any one time for years and first I’ve ever had do that. Just trash it.
Your 14 gauge wiring should be fine. I have a little heavier on mine, but then I also have one of those little pigtails that just connects to battery that I use on my 12v transfer pump and it can’t be more than a 16. Can barely see the wire inside it and it runs great for fairly long periods and probably 4’ long.

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I can’t figure out why I started blowing fuses. I used the pump for several house and roof cleanings and it functioned perfectly. Then, during a roof cleaning it started. I blew every fuse I tried, from 10amp up to 25amp. I didn’t change anything with the set-up so I can’t even guess as to what caused the problem. I’m going to try 10ga wire with a 30amp breaker and no more than a 2-3’ run to the battery. I have a remote control that I want to install also. If this doesn’t work then I’m going to downstream until I can afford a booster pump.