Pressure water system problem!

[xmodlaw]

I have what I hope is an easy question to answer.  I have a 1989 C-34, which I am new to.  I filled both water tanks some weeks ago and shut off the valve to the forward tank.  I've then gradually used up the stern tank until, last night, nothing came out.  Then I closed the stern tank valve and opened the forward tank valve to begin using that.  Hit the water pressure panel switch...and silence.  No pumping action and no water.  It's as if I burned out the pump motor, but I only ran it for a few seconds when no water was coming out.  Perhaps I have an air blockage, but then why is the pump silent?  I confirmed that the forward tank IS still full and that the valve (handle) to it is open.  
 
 What gives?  Do I somehow have to prime the system again to get the forward tank flowing?  And, why is there silence when I hit the panel switch?
 
 Thanks for any advice!  I'm stuck with bottled water until I fix this!
 
 Art Levine

[mitch brown]

Art-
 
    I assume you checked the fuse in the panel. It sounds obvious, but you never know. I do the same thing with closing off my starboard tank, and emptying the stern tank first. I have never had to manually prime the pump when opening up the starboard tank. I think it self primes. I have run the pump dry (accidently) for several minutes before without burning it out. It sure sounds like a power problem to me. Good luck with the troubleshooting.

[Ken Juul]

I recently had to rebuild the water pump in my '90 because of leakage from the diaphram.  I have a Shurflow, can't remember the model #.  In researching the repair, Shurflow states that it will not hurt the pump to run it dry.  I agree with the previous statement about power supply.  Could also be a stuck pressure sensor. I would check for voltage at the pump. If you have power, try bypassing the pressure switch to see if the motor works.  The pumps are self priming, as long as the water can get there.  It is gravity fed.  Must have an open vent to work.  Make sure the Vent in the stanchion hasn't been plugged by some industrious insects.  I got my parts from Boat US.  The diaphram was in stock, but they can order anything they don't have.  Their price beat the price from the manufacturer.  I think West marine also has a good supply of parts, but Boat US was closer for me.