Troubleshooting fresh water pump

[Allan Frey]

I have an odd problem with a two year old Shurflo fresh water pump, model 3901-0216.

I saw a small reduction in water flow rate; about 2/3 typical rate. Then, after a few days of this, the pump did not turn off when the faucet was closed, as it normally did (no accumulator). I checked all the faucets and they were closed. I ran water out of all the faucets to purge any possible air. The strainer is clean. The water tank is almost full and the fill cap is closed. There were no pipe leaks apparent. I reset the breaker several times and also turned off the breaker for several hours. When the breaker was turned back on, I still had continuous running of the pump.

That evening, the pump “fixed itself”; it just started operating normally. The water flow rate was still reduced. It worked normally most of the next day; then it started running continuously the rest of the day and all the next day whenever I turned the breaker on.

I have not heard of this kind of problem with these pumps. I don’t know if the reduced flow rate and the intermittent continuous running are related. It is an interesting problem. Any suggestions?

Thanks
Allan

 

[Rich Stidger]

These Shurflo pumps have a triple valve pumping chamber. I suspect that there is a problem with one of the pumping chambers/valves. Thus the 2/3 volume and if the valve was not closing, the pressure would not satisfy the pressure switch and it would run continuously. I would pull it apart and do a rebuild. The triple valve pumping body is available as a replacement part.

 

[Bill Roosa]

dito Rick's assessment. The "mushroom" valves get mineral deposits on them over time and need a good cleaning. There are actually 4 valves in the body, 3 in and one big on in the center. i've used a toothbrush and white vinegar successfully with out taking the valves out of the housing. If you do have to take the valves out use the blunt end of a toothpick to push the "stem' of the mushroom through the retaining hole and BE CAREFUL not to rip the rubber

 

[Stu Jackson]

The troubleshooting guide for these pumps is available, if you don't have the manual, download it from the internet.

 

[Allan Frey]

Thanks Rich, Bill and Stu for the guidance.

Stu, I did get the troubleshooting guide and looked in the archives first, but they did not have this kind of problem listed.

allan

 

[kloudie1]

Shurflo

Trash in outlet check valve of one pumping chamber.. as Bill and Rich suggest. Doesn't take much.. pinhead size piece of sand or calcium deposit.. the outer head and pressure switch housing come apart pretty easily without taking the drive side apart.. Best to take it out of the locker to work it. This shows the pressure switch off .. the three screws around the outside will allow access to the valves and diaphragms..

 

[Stu Jackson]

http://www.shurflo.com/marine-produ...aqua-king-fresh-water-pumps/default.html#tab7

Take a look at one of the PDF documents, shows blow up pictures of the parts.

Good luck.

It may not be specifically in the troubleshooting guide, but Calder and the helpful advice from the skippers here sure covers it all.

 

[Ron20324]

You should have a filter before the pump.