ShurFlo Model 4808 RV Pump Prime Issue

[edaa53]

This POS hasn't ever self primed since new. Factory no help so I'm ready to purchase another pump for my 5er. Full model is 4808-101-E65. Install docs states "any mounting position". Tried several. Any brand you all would recommend? Thanks. Ed

[hamm2018]

We went with a Remco brand in December when I had to replace a water pump. We purchased a 4.0GPM model. When I first hooked it up, I had suction connected to discharge and discharge to suction, so it would not prime.

[ntrsandman]

Age of the pump is not mentioned.

Could be a defect in the pump since the pump has been positioned several ways and the plumbing has been double checked, and all related materials have been read (hopefully). Defects do make it to market no matter the item.

I probably would feel the same way if a pump did not work properly since new.
Exchanging for a replacement would be my first choice if problem when new, then getting another brand/model would be considered if the same problem occured. (If all plumbing/connections are correct) JMHO

[creativepart]

Carefull what you buy. We had the 4808 and while it primed just fine I felt it was too loud and not powerful enough. So on one of our trips a bought a twice as expensive 60 psi pump, not sure who the manufacturer was. Turns out it was twice as loud and used twice the amps. It even made the lights in the bathroom flicker when it was running.

I put the 4808 back in and now we marvel at how quiet it is and how well it works.

I’d guess if your 4808 isn’t priming then it’s either something wrong with that specific pump or with your water system.

[NXR]

Originally Posted by edaa53

This POS hasn't ever self primed since new. Factory no help so I'm ready to purchase another pump for my 5er. Full model is 4808-101-E65. Install docs states "any mounting position". Tried several. Any brand you all would recommend? Thanks. Ed

4808 or 4008? I do not see a 4808 on the Pentair Shurflo site but I see that exact part number in the 4008 series.

When trying to prime the pump do you have one faucet slightly open? If not then the pump cannot prime because it's pushing against a closed system. If a faucet is fully open it may not prime either.

Have you double-checked the winterization valve at the pump inlet to assure it is set to draw water from the tank?

Have you removed and checked the inlet screen to assure the screen is not plugged with garf?

Ray

[Old-Biscuit]

Shurflo have 2 models with internal Bypasses
4048 which is a 12VDC 4gpm/55psi rated pump
4008 which is a 12VDC 3gpm/55psi rated pump

Both are self priming up to 6' lift
Provided:
Correct DC Voltage, clean inlet strainer, good pickup tube and NO air leaks on suction side of pump (strainer, fittings, casing etc)

Replacement
ANY 12VDC potable water pump

[Capacitor]

Old biscuit, awhile ago you posted a way to adjust the psi screw and bypass screw. Do you still have it?

[Old-Biscuit]

Originally Posted by Capacitor

Old biscuit, awhile ago you posted a way to adjust the psi screw and bypass screw. Do you still have it?

Down & Dirty Method..........4008 & 4048 models

https://lazydazearticles.blogspot.co...Shurflo%204008

[Capacitor]

That’s it, thank you. Not sure if this could help the OP as he is losing prime. There has to be a leak on the inlet side.

[NXR]

Originally Posted by Old-Biscuit

Down & Dirty Method..........4008 & 4048 models

https://lazydazearticles.blogspot.co...Shurflo%204008

As an aside, this summer I noticed my 4008 pump stuttering but only when the rear sink was used, hot or cold. That sink probably is the closest to the pump in terms of piping length.

When I looked at the pump it was vibrating so bad with that sink that I was afraid something was going to break. But it only happened on one of three sinks, no toilets, and not the shower.

I could find nothing wrong with the sink so I started tweaking those screws. The pressure adjust one was the one that fixed it, maybe 1/4 turn.

Other than perhaps dislodging a piece of debris in the 3 year-old pump I have no explanation. But it's stayed fixed for the past six months.

Ray

[edaa53]

You are correct - Mdl 4008. My mistake. Pump inline filter clean. Winterize valve closed - water tank valve open. Even when I winterize I have to pour antifreeze into short tube to get pump to prime. Go figure.

[NXR]

Originally Posted by edaa53

You are correct - Mdl 4008. My mistake. Pump inline filter clean. Winterize valve closed - water tank valve open. Even when I winterize I have to pour antifreeze into short tube to get pump to prime. Go figure.

If you disconnect the inlet hose and turn the pump on with one faucet inside cracked open, do you feel any vacuum when you put your finger (slowly) on the pump inlet?

How about when you disconnect the inlet hose and the outlet hose?

If not and it's still under warranty, get a replacement. The 4008 has to be one of the most popular water pumps in RVs. If it had a design defect a lot of people would be screaming but they're not.

Ray

[Mudfrog]

I replaced the Shurflo on ours after it leaked and ruined our carpet. Went with a 3gpm, 45psi Seaflo pump. Those specs were a close match to what the Shurflo was. It is a tiny bit noisier than the old pump but it doesn't bother us any when it's in use. Going on two years without any issues. Amazon has it right now for $50.

[edaa53]

Just to answer all the excellent suggestions to solve my problem. No air leaks, etc. Good voltage at pump (13.12VDC). Filter(s) good. Etc. I did order the SeaFlo 3.0GPM 45PSI unit. Installed and it primed perfectly. Sure does rattle a lot and water pulses rapidly - almost a hammer effect - as pump runs. Can't be good for the water lines. There is a design difference - the SeaFlo has a 3 chamber diaphragm - ShurFlo has 4. Might have to just get another ShurFlo 4008 or maybe HydroMax? Live and learn again Regards. Ed