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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 26025
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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I have a Craftsman shallow well pump model 390.251481. It

Customer Question

I have a Craftsman shallow well pump model###-##-#### ***** has only been in use for less than 5 years. Recently water pressure from the faucets decreased and the pump just keeps running and won't shut off. We have checked the well and intake pipes there, changed the water filter, checked the pressure in holding tank... None of which helped. Now we are thinking the pump may be the issue. Please advise how to diagnose a pump problem. Thank you!
Submitted: 1 year ago.
Category: Small Engine
Expert:  Curtis B. replied 1 year ago.

Is pressure building? If pressure is ok, the pressure switch is not working. It is what cycles the pump motor on and off.

Expert:  Curtis B. replied 1 year ago.

http://s.sears.com/is/image/Sears/PD_0042_390_U217-1202?wid=400&hei=400

Customer: replied 1 year ago.
The pressure is poor, maybe about half of what it should be, if that. Could something need adjusting? Also, could the impeller be bad and not work up to par?
Customer: replied 1 year ago.
We are afraid to let the pump keep running, as it doesn't seem to shut off. What is a reasonable time to allow it to run to check pressure without risking damage to it?
Expert:  Curtis B. replied 1 year ago.

The pump will not be damaged as long as it has water ! Is it pumping water?

Expert:  Curtis B. replied 1 year ago.

A worn impeller will keep it from building pressure.

Customer: replied 1 year ago.
it's pumping water, but the pump will not shut off, even after an hour of not running water.
Expert:  Curtis B. replied 1 year ago.

The pressure switch can be adjusted down so it cuts off on lower pressure.

Expert:  Curtis B. replied 1 year ago.

Pressure switch will have adjustment for lowering the tension in the cutoff switch.

Customer: replied 1 year ago.
Alright, thank you, ***** ***** try that out and see.
Expert:  Curtis B. replied 1 year ago.

OK, thanks!

Customer: replied 1 year ago.
There is no pressure switch on our pump or tank. :(
Expert:  Curtis B. replied 1 year ago.

The pressure switch is where the electrical comes into the unit! It has to have one!

Customer: replied 1 year ago.
Ok, sorry, this is my first experience with these problems. I'll check that when I get out of work. Thanks again.
Expert:  Curtis B. replied 1 year ago.

# ***** on parts list.

Expert:  Curtis B. replied 1 year ago.

http://www.searspartsdirect.com/craftsman-all-products-parts/model-390251481/0247/1050000/10037370/00001.html