Shurflow 4900 series pump problems

[azbohunter]

I have the following problem with my water pump Shurflow 4900-0211 and am looking for advise from someone who may have knowledge of this pump.
Two things:
#1 My pump burps occasionally when running off the fresh water tank.
a. I have checked every possible connection and or place where water could leak and find nothing.
b. I replaced the diaphragm in the pump and it still burps.
#2 When I am hooked up to city water, eventually my fresh water tank over fills and starts dripping out of the overflow tube.

My first thought was the diaphragm must be bad and I was losing pressure and it was also allowing water to pass through to the fresh water tank. I replaced the diaphragm and results were no change.

Could the diaphragm housing have a hair line crack that I can't see? That is my next thought?

Or, could the valve that shuts off flow to the fresh water tank be leaking and allowing water to pass through into the fresh water tank?

I realize there may not be a correct answer without tearing things apart but maybe someone else has been here/done that?

[azbohunter]

Through process of elimination I found the valve assembly on my water pump to be the problem. I had replaced that a few months ago and thought I was good but it was a short fix. I took the pump out and hooked a garden hose to the outlet side of the pump and had a steady drip from the inlet side. I removed the valve assembly (there is no check valve in this model pump) and inspected it, cleaned it and put it back together, same problem. Hit the local Ace Hardware and got a 1/2 inch check valve and put in the line on the suction side of the pump and after several hours I see no leaks and everything seems to work. Keeping my fingers crossed.
Thanks to all who added helpful suggestions! Dick

[azbohunter]

Old-Biscuit wrote:
Petroleum jelly is not good for o-rings.....it can deteriorate them.

A o-ring in good shape doesn't really need anything.
If using anything..plumbers grease

Well, I learned something new today, thanks Old-Biscuit!

[Old-Biscuit]

Petroleum jelly is not good for o-rings.....it can deteriorate them.

A o-ring in good shape doesn't really need anything.
If using anything..plumbers grease

[azbohunter]

Old-Biscuit wrote:
The Shuflo Extreme series pumps do not have internal check valves....just a 4 Chamber Diaphragm Valve Assembly.

I would suspect the 'fresh water fill' valve on your water panel is leaking by, your fresh water tank overflowing when on city water makes it suspect, and you have replaced pump diaphragm assembly already.
System pressure drops enough for pump to start/stop and your pump 'burp' is pump start/stopping to get pressure back up.

Are you using a 'pressure regulator' when hooked up to city water?


Extreme Series.......


Classic Series......

I usually do use a pressure regulator but even when hooked up to water supply with known low pressure it does the same! I suspect the water fill valve also, I will have to look more into that. I have disassembled it, wiped it clean and put a little petroleum jelly on the o-ring. It looked good but.....

[azbohunter]

Thanks for the input guys, I am too thinking that a check valve inline might be the answer, just not quite figured out where maybe to put it.
They make some rigs esthetically pleasing but sometime simple is better in the long run. I have a panel with 3 valves, one this way for fresh water, one this way for fresh water fill, one this way to winterize, one this way for ??
My old trailer had a hole in the side with a cap over it, you stuck the hose in and filled it till it ran over, not as fancy but it sure would be easier to figure out right now! humor.....

[Traveler_II]

I had the same problem, replaced the check valve in the pump, didn't help. Put a check valve in line and stopped the problem.

[Old-Biscuit]

The Shuflo Extreme series pumps do not have internal check valves....just a 4 Chamber Diaphragm Valve Assembly.

I would suspect the 'fresh water fill' valve on your water panel is leaking by, your fresh water tank overflowing when on city water makes it suspect, and you have replaced pump diaphragm assembly already.
System pressure drops enough for pump to start/stop and your pump 'burp' is pump start/stopping to get pressure back up.

Are you using a 'pressure regulator' when hooked up to city water?


Extreme Series.......


Classic Series......

[azbohunter]

dbbls wrote:
There is a check valve in the pump. Sounds like your is bad. You can rebuild the pump, get a new one, or install a check valve between the pump and fresh water tank.

I was aware there was a check valve and had considered that but I was thinking that kept water from flowing back through the pump when hooked up to city water.

Can you explain how this works, not doubting you, anxious to understand it better!

Thanks,
Dick

[dbbls]

There is a check valve in the pump. Sounds like your is bad. You can rebuild the pump, get a new one, or install a check valve between the pump and fresh water tank.