water pump questions

[nmcat]

I have a 2019 E-Pro FB19.
I’m on a big trip (for me), so I’m on the road and am trying to figure this out.
I did some searches, both here and generally, but can’t find the answer to my actual question.

I knew I was getting low on water when I took a shower and ran the fresh tank dry.
Before I could get to the pump switch, the water pump stopped by itself. (I did turn it off when I finally reached it.)

Now, about a week later, I put a little water (6 gallons) in the fresh tank.
Although the pump runs I’m getting no water at the faucets.
The pump runs and sounds normal.

I unhooked the supply side of the pump and was able to blow into the fresh tank and hear bubbles. So I sucked enough to get water to the supply fitting to the pump. That tells me no obstructions.

Which brings me to my main question. Is the suction of the pump enough to feel by hand?
I’m wondering if, when I ran the pump dry the pump stopped because it overheated. That’s why it runs now, it’s cooled down. And maybe that overheating, with no water to cool it, somehow damaged the diaphragm?

I have a spare at home, I thought I brought it, but evidently not. That to say I hate to go to an RV store and pay big bucks, when I have a good one at home.
Yes, I know, it would just be an expensive lesson, but, if I can avoid the expense part and just learn the lesson, I’ll go that route.

Thanks lots.

[SafariBen]

The only spec I found is six feet of suction, which isn't much. Might not feel that with your thumb, probably would feel it with more sensitive skin.



Try to release the pressure on the output side, even at the pump until you get it primed. The diaphragm pump should run dry with no damage for many minutes, and it wasn't dry when you ran out of pressure, is just got airlocked, but everything inside was still wet and had enough water to lube anything, not that it needed water. I'd think it was a total coincidence if something happened to damage the pump. More likely it sucked a little water and built pressure to shut off. Or possibly sucked a bit of garbage that jammed the valves open, but that wouldn't explain shutting off. The cover usually comes off with six screws to examine the valves and diaphragm if you can't get it to prime at all.

[Old-Biscuit]

They are diaphragm pumps that only move back/forth maybe a 1/16th of an inch and can run dry w/o damage (water is not necessary for lubrication)
*I found mine running after over 8 hrs and that pump was still being used for over 16 yrs.

Why only 6 gallons put back into fresh water tank........fill it up/turn on pump and open a faucet coldside and let it run/prime

[High Road Travelers]

Since you put water in the tank, how long have you let the pump run to see if it will prime itself? Normally these pumps can run for a good while with no water, so don't be afraid to let it run a reasonable time to see if it starts pumping water.
Thanks,

[d23haynes57]

If the tank is not tilted right a few gallons will not be enough for it to prime. You also just be filling up the water heater. Fill the tank and see what happens.

[nmcat]

SafariBen - I left a tap open, but no go.
I’ll pull it out and take it apart - Thanks

OldBiscuit - that’s all the water I had available at the time. I’m boondocking. I’ve been doing without water in the tank because it’s getting down to freezing and below a few nights here and there. I did check for broken lines, fittings etc, but found nothing amiss. It got to 34deg a couple nights and 27deg one night. Days are 50 or 60. No driving when it’s that cold, just parked till it warms up.

High Road, I let the pump run for, I’m guessing, 10 minutes or maybe more.

d23 - the trailer is level. I was able to suck water to the pump. (Hadn’t tried that trick since my gas siphoning days - and that was a long long time ago.) But before I sucked anything, I blew into the line and heard bubbles. There’s also a little bleed valve, at the tank, that I opened and got water. All that to say, I believe I’ve got enough water.

All, I’m out in the woods mostly, so I don’t have all the stuff I usually try at home. Another thing is buying something on the road, I can’t take it back too easily. I’ll just be passing through.

I’ll just make the Solar Shower work, I suppose.

FWIW, this is the pump I have, I just put it in last fall, so it doesn’t have hundreds of hours on it or anything like that: https://www.vevor.com/diaphragm-pump...p_010783011244

Thanks again. I guess I’ll just have to disassemble to troubleshoot.

[SJ-Chris]

I had a similar situation happen on one of my RV water pumps. Then when I put water in the fresh water tank, the water pump sounded like it was pumping but no water came out.


Then I read somewhere about "priming" the water pump by forcing/helping some water into the inlet side of the water pump while it is running. I wondered how I might do this in the tight spot that it was installed. But then, to my luck, I noticed that my system was actually already plumbed with an extra vertical water pipe t'ed into the supply/inlet line going to the water pump. This extra vertical pipe extended up about 18" to a spot that was easy for me to access, and it had a simple twist-off endcap that I could unscrew and pour a cup of water down this vertical pipe while the pump is running and that would prime the pump and create suction. Then I quickly capped the end of this vertical pipe and the water pump was correctly drawing from the fresh water tank.


So take a look at your inlet side of the water pump. Trace the pipe (likely pex plumbing) back to the fresh water tank. See if you are lucky enough to have a vertical "T" pipe connected to this inlet pipe that you can access to help you prime the water pump. Let me know. I'd be thrilled for you if this fixes your problem!


Good luck!
Chris

[nmcat]

SJ,
I had similar thoughts about priming.
The pump is billed as ‘self priming’, which led me to try and feel if the pump was sucking at the inlet.

Unfortunately the supply line is all lower than the pump.
If I were at home and had my compressor and associated fittings I could try to pressurize the tank. But if i were at home I’d have a full tank of water.

Thanks for the idea though.

[d23haynes57]

Those pumps are self-priming unless the check is slightly stuck open.

[SafariBen]

One red flag in that add is the teflon tape. Those fittings are usually a rubber gasket type, they don't rely on the pipe threads sealing, so don't use tape. Tape gets into the valves and the tiniest bit will keep it from pumping air, even if it pumps fine once it gets full of water. If you can suck on the outlet while the pump is running, it will either prime and pump, or not. If not, take it apart and see what's up.

[nmcat]

SafariBen.

I tried one last thing, I put the supply side in a jug of water, right next to the unit and.... nada. So I broke down and just bought a new pump and it took right off pumping water. I'll take the old one apart when I get home in a month or so.

I may find a bit of teflon tape in there who knows. I try not to put tape anywhere near the flow, but I'm not a plumber by trade, only by necessity.

I've got flow now,

Thanks all for your help.

I'll let you know in a few weeks what I find, if anything, in my malfunctioning pump.

PS..I wan't in the frame of mind to check flow, in or out of the new pump ( as I should have) so no answer to that question.

[dabrooks]

One red flag I saw in your original post was that when you ran out of water the pump shut off by itself. In my experience the pump shut have kept running. Maybe someone else can comment as to why that would happen.

[SafariBen]

I sure couldn't come up with any logical explanation. Bearing/eccentric failure I suppose could lock up the pump and "shut it off".