Water Systems

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hartps

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Jul 8, 2006
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When hooked up to city water our water holding tank also fills...any ideas???? Thanks for the input.
Doheny Dolphin
 

Tom

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You might have a valve that directs water from the city inlet to either the tank or the RV plumbing. The valve could be set in the 'tank fill' position.
 

Ron

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As Tom mentioned you probably have the fresh water tank fill valve in the fill position. If you have a reverse osmosis system installed these are sometimes plumbed so the excess discharge water goes to the Fresh water tank.  Please provide some details like year and make of the RV.  Possibly with this info somebody may have experience with the same make rig.
 

Steve CDN

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Would it be possible to take a photo of your water connections compartment?  If so, you can attach the photo to your  Forum reply using "Additional Options" at the bottom lft of the message composition window.

Many RV's have a system of valves that direct water into various locations such as filling the holding tank, or flushing the system when winterizing, and others have valves to bypass certain systems.

With more info about your RV and perhaps some pictures, we can try to figure it out.
 

John From Detroit

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There are 4 ways a water tank can be filled by hooking up to city water, Two are problems

1: Quick Fill, this is a valve that allows the supply tank to fill from the city water connection.  If this valve is set to FILL it fills
1a: Same valve, deffrective (Problem #1)  Note, these valves do not often fail.

2: You have a special "Fill 'er up" fitting, and hoked to it (never seen one, but have often considered one back in my trailer days)

3: bad check valve in the pump line (problem)
 

Gary RV_Wizard

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If you do not have a "tank fill" valve in the wrong position, then the problem is a failed check valve in the water pump. The pump check valve is supposed to keep water from leaking back into the tank when the system is pressurized. A pump check valve can be fixed by replacing the pump head assembly or by replacing the entire pump. Rv shops will generally try to sell you a new pump, but replacement pump head kits are available as well. About $60, last I checked.

I suppose you could just add a standard plumbing check valve in the pump intake line (between pump and tank) to supplement the existing check valve, but I've never tried that myself. And you might have trouble finding a check valve for a 3/8" water line in local stores, since 1/2 " is the smallest size commonly used in household plumbing.
 

Steve CDN

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Gary,

A pump check valve can be fixed by replacing the pump head assembly or by replacing the entire pump

Is the pump check valve inside the pump head assembly, and an integral part of the pump, as opposed to being external?

trouble finding a check valve for a 3/8" water line in local stores, since 1/2 " is the smallest size commonly used in household plumbing

Despite the diameter difference, if plumbing adapters were used to fit the 3/8" line, would it work nonetheless?
 

John From Detroit

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RV Roamer said:
And you might have trouble finding a check valve for a 3/8" water line in local stores, since 1/2 " is the smallest size commonly used in household plumbing.

Having just shopped for a 3/4" swing check valve for use in a gray water line..... I agree

however adapters from 3/8 or even smaller to 1/2 inch can be found and work well

I'm thinking a swing valve is better on the inlet side than a spring valve (i use both kinds depending on where it is going)
 

Gary RV_Wizard

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The Shurflo pumps I have looked at have an integral check valve. I don't know if that is true of all models or of other makes,  e.g. Flojet or Jabsco, but I suspect so.  The pump needs a check valve to function properly in a typical Rv water system, so why not build it in all the pumps intended for that application?

Yes, you can use a 1/2 inch or 3/4 inch check valve with appropriate adapters to reduce to the 3/8 tube usually found in Rvs.
 

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