Understanding Fresh Water Fill, Shutoff, etc

[Dick Simonis]

Help me understand how the fresh water fill and auto shut off functionl

Last night, in preparation to move to BCS for some work, I filled the FW tank until it shut off and read 98% on the CMP  panel.  This morning it still read 98 % but with a minimal amount of water use such as making coffee, and normal AM stuff the level fell to 71%.

With that in mind what might be going on??  What controls the auto shutoff valve??  Also when it shuts off I still cannot run the water pump until I manually shut off the water fill switch.  One would think that if the water fill is nothing more than a solenoid valve one it was commanded off either by a float switch (?) or the inside switch it would be off and not longer bypass the pump.

The coach is perfectly level and there is no indication of a water leak nor anything from the overflow line.  However occasionally the CMP reads the FW tank as (Uncal).

Thanks for any insight.

Dick

[William Jordan]

Good question as I've had the same thing happen. However On mine the pump will work with the water fill on .. Not a good thing ... I burned up a pump that way as the auto fill stopped filling but the pump ran continuously pumping water in and out of the tank,  you can hear water running into the tank. . Happened again with the new pump until figured out what was going on.  The new pumps thermal shut off saved it.
The auto shut off on the fill seems to have a mind of its own at times

[David T. Richelderfer]

Interesting!  My Marquis does not shut off its autofill valve automatically, and the water pump and autofill valve are not connected electronically.  That is to say, the autofill valve and water pump operate independently and by separate switches.

Like Mr. Jordan said, when my autofill valve is open/on, then if the water pump is on it will pump endlessly too.  Thus, I always turn off the water pump when filling the fresh water tank.  As soon as the water tank runs over from being full I close/shut off the autofill valve and turn on the pump.  If the water tank's overflow is gushing, which it will because that's how I know it's full, then I turn on the faucet at the water bay to stop the siphoning action.  I can fill the water tank to overflowing and the indicator on the Silverleaf will indicate it's full, but rarely can I get the siphoning stopped quickly enough to hold the full status on the indicator.  The thing that bugs me is after filling the water tank and moving to a new destination (say, a few hundred miles away), the water tank indicator rarely reads over 75% full.  At every stop sign or downhill street, due to braking, the water will flow out the overflow until the tank gets to 75% or so.

[William Jordan]

That is interesting . I assumed all Marquis of that era had auto shut off . Mine always shuts off and never overflows. Perhaps it's just not working on some and overflowing. My problem is like dick that it stops at 100% on the Aladdin (it did read 95 until I reset it) but just a day later it will sometimes be only 70% with little or no use and no overflow , I've looked.

[steve zannella]

I had this problem a few years ago with the water pump circulating water in and out of the water tank and the pump not shutting off. The problem was resolved with a new water pressure relief valve. This device is designed to open and close based on excessive water pressure and a signal from the alladin system to open and allow water into the water tank. For some unknown reason the pressure relief valve would not hold water pressure above 30 PSI my guess is that the spring became weak and allowed under pressured water to enter the tank.
Anyhow replacing the pressure relief valve fixed the problem.
A short term solution is to place a gate valve before the pressure relief valve and close leave it closed until you want to fill the water tank. This will stop the water pump from running continuously.

As to losing water from the water tank while driving, raising the height of the water tank overflow hose loop should help stop tank siphon overflow. Had that problem also.

[Dick Simonis]

Does anyone know how the auto shut off works??  Is there an actual float switch or valve that does this or is it a tank full signal from the level sensor??

[steve zannella]

There is no float switch for the fresh water tank it works by the alladin system when the fresh water sensor determines the tank is 100% is releases an electrical signal to the pressure relief valve to close. You can determine how many gallons of water are in you tank by modifying the tank calibration setup in the alladin settings.

If the pressure relief valve is not working correctly IE: too much pressure for the valve then water will continue to flow to the tank whether the alladin senses 100% full or not. The flashing AF will go out but water may continue to flow into the tank.

The pressure relief valve was designed for 65 PSI anything above that pressure would opened the valve and allowed water into the tank.
In my case the valve weakened and would allow water at 35 PSI into the tank so anytime the water pump was activated greater than 35 PSI it pumped water past the valve into the tank thus creating a perpetual water loop.

I could not find a exact replacement valve at 65 PSI so I put a 100 PSI valve in its place.\

All is good.

Steve

[william harrison]

 I got tired of not being able to completely fill my fw tank on my 03 Marquis so I installed a switch
that provides 12v to the shut off solenoid when I fill the tank then just wait for overflow then shut the
solenoid off

[Joel Ashley]

Dave, I like Steve Z.'s note about the overflow loop.  I'd check that yours is still effective and above the max water level enough to prevent slosh-out.  It fixed his, and you have similar rigs.

-Joel