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Auto Fill (?)Water System Not Shutting Down


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First time out with our new Monaco.  Hooked up my pressure regulator, set to 50 psi and my filter to city water in an RV park.  Hit the auto fill switch and could hear water entering the tank.  The system is supposed to turn off when the tank is 98% full.  While waiting for the system to turn off, heard water running out of the coach on the other side, walked over to see water coming out of the overfill? Tube in front of the rear passenger wheels.  There are two discharge lines in this location, one small and one larger, the water came out of the larger line.  

Obviously the auto shut off is not working, anyone have any insight into what to look at first?  Assuming there is a solenoid valve back in there somewhere?   The red light above the switch is not lighting up as well. 

Switch has three positions: 

  • UP: Auto fill
  • Middle: Off
  • DOWN: City Water

When I switch it to city water mode, I’m still getting a steady drip out of that larger discharge line.  Currently, I’ve got the switch in the off position and using  the internal water pump.  

The switch is on the lower left in the left wet bay.  A bit of a mess, beginning a major clean up!

Anyone have any experience with the trouble shooting the operation of this system?

Any help is greatly appreciated!!


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How does autofill work...does it sense the level and shuts an electrical solenoid on the fill side of the tank off?

If that is the case, then possibly the level sensors aren't working and not sending the 98% full message back to Aladdin...back to the OP: Does your level sensor work?


Or does it sense water coming out of the vent and shuts off the water solenoid?


I assume it doesn't have a float switch inside of the tank to mechanically do the above based on the need for Aladdin to be in play.

Just curious as I am developing my own control system in place of Aladdin....

I might implement both as a fail over.

Edited by DavidL
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Your system looks similar to my '09 Dynasty. The autofill system was the first thing that went out on me when we 1st purchased it.

The problem you describe might be in the switch itself or a tank level sensor. I wound up taking the whole system out because of repeated failure of the solenoid valve. I took the electric valve out and replaced it with a stainless bulkhead mount ball valve similar to the valve you switch flush water to either gray or black tank. I mounted it up high and to the left of the tv cable entrance. Plenty of access there. Easily done with a few pex fittings and line. Downside is you have to watch the tank level on the other side of the coach to know when its full enough to shut off. Upside, it will never again be the cause of the system not being able to pressure up, because when the valve goes out, the pump will run water out of the tank and then back in, not building pressure. It might sound a bit extreme, but I'm happy with a system that won't fail..............Good luck, Theo

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Hi Bob,


On my 2008 Dynasty, the switch controls an electrical 2 way valve connected to the water system near the water pump.  Mine failed and the water continued to run.  I replaced mine with an identical valve,took the old one apart and found it to be clogged with rust, etc.  you can also purchase a rebuild kit.  

I purchased mine from Galloup/ Smith instrument.  Part # 8210G94 1/2 inch Brass 2 way NC 12VDC 40 PSI CV 4 ASCO valve.



not hard to replace..


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A water softener eliminates water system problems. You spend more $$$$$$ ideling in 5 years than what it costs, and the maintenance. We had one 10 years full timing and never had any problems with the water system and thier components.  Placement is an added option in the use.

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I had the same problem with my 2009 Dynasty, Did what TigerMar did, replaced the same valve and took care of the problem !

Also I had an issue that randomly, water would come out of the supply hose when running the pump. The first time it happened I was on the road and stopped at a rest stop, used the toilet and left the water pump on. I got out of the coach to do walk around and noticed water running out of the wet bay. Water was comming out of the hose, so I turned off the pump and put a cap on the hose end. This issue would come and go, was driving me nuts ! I found a check valve was sticking. It is inline just after the water pump.


It is inline just before the water pump.

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If the water fill valve is overfilling the tank and continues to drip water, the valve probably has dirt in the pilot valve or diaphragm.  The fill valves that I have encounter, are differential pressure diaphragm valves that have a small solenoid operated pilot valve.  The diaphragm has a small bleed hole and when the pilot valve opens the back pressure on the diaphragm is released and the valve opens.  The pilot than closes and the water pressure builds on the back side of the diaphragm to close the valve.  If the pilot is not closing or the bleed hole is plugged the valve will continue to leak.  They can be repaired by removing and cleaning the parts.  

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Your wet bay looks identical to my 07 Beaver PT (came off the Oregon line 09/06, so might have a lot in common).  First thing I'd do is go into the Aladdin setup menu (I think the code is 1218, but on my way to Africa so can't verify anything for another 6 weeks).  Calibrate the full and Empty raw sensor values.  Mine were way off and they seem to drift a little over the months).  I also recalibrated my gray and black tank raw values based on actually measuring water down the drain....

Next thing is I replaced that Top Hat solenoid with one that had better pressure specs including negative pressure so your tank won't be sucked dry if the city line is draining for an underground repair someplace...  It was an industrial one from eBay, found the link , https://www.ebay.com/itm/121358112687

Thirdly I rearranged the inline check valve to be BETWEEN the auto fill solenoid T and pump pressurized T line.  Reason being I leave my Auto fill ON and pump ON when the CG has low pressure.  What happened the way the factory plumbed it was I'd be taking a shower with good pump pressure from the tank... Tank drops below 80%, solenoid open and pump pressure way higher than 20 psi city so the pump cycles water back into the tank via the fill line and my shower dropped to a trickle...


Edited by amphi_sc
Link to valve I used
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