Water pump symptoms

dangerdave · 05-10-2018, 06:53 AM

2018 Jayflight 34RSBS. On fresh tank, not city. Water pressure somewhat low with intermittent air sputtering from faucets. We recently had pump serviced for being loud and dealer rerouted some lines to stop rubbing, so they probably had it disconnected.

Just seems like we've run it enough for the air to have gotten out by now.

Additionally, after SOME faucet uses, the pump just stays on purring quietly but seeming to not achieve anything. I have to turn the faucet back on FULL and then OFF...and the pump catches up.

The pump does not cycle randomly when the faucets are off. I've had that issue before. No leaks anywhere.

Could this just be an "air in the lines everywhere" type of issue that has to be worked out of the system? I would think the pump would be cycling randomly if that were the case but I'm no expert.

Thank you very in advance for any useful advice!

Of course we're camping now at the start of the season so it's pretty aggravating.

RVhiker · 05-10-2018, 07:09 AM

Here's my suggestions
1) Using the pump, run water through each and every hot water and cold water faucet (including the outside shower) until the water comes out without sputtering. Don't forget to run water at the toilet.

2) If the sputtering is fixed by 1), great. If not, it probably means that your pump is sucking air --- and water from the tank --- at the same time. That is, there is an air leak on the suction side. You could check all the suction line connections - don't forget the strainer, if there is one. If the strainer has a cap on it, make sure the cap is snug.

stateboy · 05-10-2018, 07:21 AM

Here's a recent thread on a similar issue for some ideas.

https://r.tapatalk.com/shareLink?url...8&share_type=t

dangerdave · 05-10-2018, 07:36 AM

Thank you both!

Can you point me to what the strainer / cap looks like?

I will try the running water test too.

cabinetmaker · 05-10-2018, 07:42 AM

You said you had pump removed and some lines rerouted...I think that is your answer.

This would allow air in lines. I would run all faucets (don't forget outside shower) and let them run for a few minutes. Should solve your problem.

If not you have a faulty pump or air leak / water leak.

Jagiven · 05-10-2018, 07:47 AM

I would suspect the inlet filter screen bowl. If it is not on correctly (gasket) or if it has hairline fractures it will do what you are describing.

My bowl was full of what looked like scratches all over it. It did not leak water, but air would get sucked through the fractures. Replaced the bowl and all was good!

Sundancer330 · 05-10-2018, 08:07 AM

Quote:

Originally Posted by dangerdave

Thank you both!

Can you point me to what the strainer / cap looks like?

I will try the running water test too.

Should look similar to this one, its inline between the pump and FWT, usually very close to the pump.

dangerdave · 05-10-2018, 10:55 AM

Thank you, and I did identify the screen bowl and it's tight.

I did the running water thing and it did eliminate a lot of air and then calmed down.

So the real symptom here now is that if I use just a little water real quick, a normal water pump burps back on and rebuilds the pressure. This one just purrs very lightly...like it's not ON strong enough to rebuild the pressure.

If I then really turn on the water to get the pump working, and turn it off, it rebuilds the pressure and shuts off. Like it's gotten a running start to finish.

So is there an easy way to increase the strength or pressure the pump is putting out?

This makes sense on the low water pressure too, and how the dealer may have turned it down to not make it so noisy.

Again, thank you guys. I don't know what I'd do without this resource!

RVhiker · 05-10-2018, 11:34 AM

Are you getting water properly at the faucets? If you turn on the water a little, do you get a little bit of water and if you turn on the faucet fully, do you get a lot of water?

The standard RV pump behaves as you describe; it's on or off. That is really the only type I'm familiar with. There are some newer types of pumps that have some sort of internal bypass that allows them to run at full speed under all water demands, but only supply enough pressure to supply the water asked for. I think the perception of this newer pump could be that it ramps up as you describe --- but I might be wrong. Could you reply with the make and model number of your pump? We or you could search for it and see what the manufacturer says about it.

dangerdave · 05-10-2018, 01:50 PM

ShurFlo 4008. it appears to be a one speed thing. Nothing fancy

I just plugged the end of the 2 foot clear plastic winterizing bypass and the problem appears to have completely disappeared. Then I remove the plug, it pulls air.

I could be wrong. I've claimed victory before here and had it snatched cruelly away. haha

Could it be that spring loaded bypass valve was the vacuum leak?

Subaru297 · 05-10-2018, 02:21 PM

This sounds like a bypass valve issue. We get the same problem in our trailer ever since we installed our accumulator tank. Sometimes it works fine and sometimes it keeps on humming indefinitely.
We can stop the humming by cycling a valve after the pump or turning the pump off and then back on. I think it builds enough pressure in the lines but it is just shy of shutting itself off due to the bypass valve. That's my theory anyway. And I have completely replaced the pump twice and still get the same issue.

Cheers

bankr63 · 05-10-2018, 02:30 PM

Quote:

Originally Posted by dangerdave

ShurFlo 4008. it appears to be a one speed thing. Nothing fancy

I just plugged the end of the 2 foot clear plastic winterizing bypass and the problem appears to have completely disappeared. Then I remove the plug, it pulls air.

I could be wrong. I've claimed victory before here and had it snatched cruelly away. haha

Could it be that spring loaded bypass valve was the vacuum leak?

I would say that's it right there. There should be a valve on the winterizing suction hose that is either not closed or leaking.

When you do a short soft burst, the pump is probably not creating enough suction because of the upstream back-pressure to get water up from the FW tank, and is only sucking a bit of air from the winterizing hose. Effectively you are having to prime the pump each time you use it because the air is also allowing the pre-charge water in the non-pressure side to flow back down into the tank. Once you hit it hard, the pump sucks hard enough to start the flow of water from the tank (reprimes itself) and then shuts off when pressure builds.

Mind you, I have never seen a spring loaded valve on the winterize hose, it is usually a 90* ball valve that turns on and off. Does this have one of the water control panels like you generally see on the 5ers?

dangerdave · 05-10-2018, 03:46 PM

I may have misspoken on it being a spring valve. It does not have any kind of water control panel either.

Thank you guys for the time taken in these thoughtful responses. They lead me in the right direction.

I've been playing with this now for a good hour and it's working perfectly. Great pressure, no air, no trying to prime itself.

Unbelievable if it holds true.

Of course this trip out we decided to bring the 2 year old grandson so the DW is more sensitive to the water working properly. I said we could use a bucket if necessary and you know how that flew.

skids · 05-14-2018, 12:28 PM

I don't know much about these pumps. I did notice an open ended hose that has a valve to the pump. Could it be that the valve is opened a bit? I think that hose is to put antifreeze into the system from a jug and if so, it would be on the suction side of the pump.

Oh, I think this may have been covered with talk of the bypass.

You may also like: