How does water pump cut off?

[26.982 amu]

Today I filled and fired up my fresh water pump system for the first time--problems! I have a plug-in voltmeter that measures the voltage of my battery, and it read less than 9 volts when the water pump was turned on. When I closed the faucet, the pump "stopped"--but the meter showed even lower voltage, indicating that the pump was not really off, but drawing lots of current through its motor without moving! Can this be right? I thought that the pump actually shut off when the faucet was closed. What gives? Doesn't this drain the battery?

Also--major dripping under the galley area beneath the trailer, along the frame. What kind of leaks am I in for? Any helpful comments?

[overlander63]

The water pump should have a pressure switch that turns to pump on when pressure drops, and off when you turn off the tap, and pressure rises.
Many coaches with copper pipes have the leaking problem. It is usually from having a small amount of water left in the pipe, and the water freezes. There are several options for repairing the pipe, from two hose clamps and a chunk of rubber hose, to completely replumbing the coach with new PEX. Most people go somewhere between, if it is only one spot leaking.

[lewster]

Vince,

Like Overlander said, plus you can get Qest fittings in hardware stores and even Lowes now that will ease the transition to a polypropylene or polybutylene tubing system if you choose to go that way. Sounds like the diaphram on your pump is going south and adding to large amp draw to it's motor. Get a re-build kit for the pump head....that should cure the problem. Or replace it for about $60 and get a warranty with the new one.

[RDM16CCD]

In your post you mention that your volt meter was reading 9 volts and less. Assuming you have a 12 volt battery system, 9 volts is way low. I think the rule of thumb is that the typical useable range is 11.7 to 12.6 volts, and that a battery reading of 10.5 volts or less means the battery is 'dead'.

A typical water pump might draw 4 or 5 amps of current, and a battery with only 9 volts couldn't even begin to drive a pump.

Do you have any other info on this, like when was the last time the battery was charged, were you plugged in to shore power, etc? I would suspect a deeply dischared, or even a dead battery, may be the reason the pump would not run.

[26.982 amu]

My battery has a solar charger that keeps it at 12.2-12.6V. It was at full charge when I started working with the water pump. I only saw the huge current drain when the water pump was on. By comparison, turning on both the overhead vent fan and the gas range fan only dropped the voltage by a volt or so.

[steelbird312]

Vince, 12.2-12.6 is not a fully charged battery!
State of charge chart for 12 volt batteries:

* 12.70 volts 100%
* 12.50 volts 90%
* 12.42 volts 80%
* 12.32 volts 70%
* 12.20 volts 60%
* 12.06 volts 50%
* 11.90 volts 40%
* 11.75 volts 30%
* 11.58 volts 20%
* 11.31 volts 10%
* 10.50 volts 0%

It is possible that in any of several locations, your electrical connections may have lost their integrity. Check every connection that includes the battery and the power from the battery to the pump (this includes through the fuse box). As old as your unit is, almost any ground for any equipment, including the batter ground, is suspect for corrosion or electrolysis.
To put your mind at ease, if the pump stops pumping, the power has been cut to the motor. Since it uses a pressure switch, cutting the power to the motor is what stops the pump, so it is not sitting there pulling power.
Hope this helps (a little)