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Old 09-25-2010, 08:53 AM   #1
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Lyndon , Kansas
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How is the fresh water system plumbed?

I have recently acquired a 30' classic. I am trying to understand how, when hooked up to city water, water is prevented from flowing through the fresh water tank. Is it simply a check valve? If so, then how is the fresh water tank filled, i.e., how would the check valve be bypassed? Is there a separate connection for filling the fresh water tank? The manual does not have this information.

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Old 09-25-2010, 09:26 AM   #2
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The water pump has an internal check valve which prevents back flow into the water tank when hooked up to city water. The water tank is filled from an external port usually located on the curb side of the trailer. You did not state what year your trailer is so actual location and access door will vary depending on the year. My 73 has a locking door which flips open and can be filled either with a hose or using the flip down door as a funnel with a jug. Why would you want to by pass the check valve? Conversly when using the water pump there is a check valve located at the city water connection to prevent water from flowing back out of the city water connection.

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Old 09-25-2010, 09:30 AM   #3
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The pump acts as the check valve to the fresh water tank when hooked to city water. There should be a small door, on the curb side of the trailer, with a fill point behind it to fill the fresh water tank. Some years did have an "auto fill switch" on the control panel that would allow you to fill the fresh water tank from within the trailer while hooked up to city water, around 1991 or so. A very nice feature.

The balance of the water system is straight forward plumbing.
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Old 09-25-2010, 11:02 AM   #4
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Classic 31 Plumbing

Here is the Plumbing diagram for the 31D I imagine it is similar to the 30, except for the shower.

There is one misleading label. at the top of the diagram where it says city water connection it is actually the bathroom sink. The city water connection is in the lower left.


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Old 09-25-2010, 01:58 PM   #5
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Smile Fresh water plumbing question

Thanks for your responses.
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Old 09-25-2010, 03:59 PM   #6
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I installed a valve that stops water going to my fresh tank. Reason, I didn't want that pressure on the check valve. They have failed but not often. But since I was re-plumbing everything I put one in. I just have to remember to open it up when I'm using the pump. The wife complained once it wasn't working and I was off on a hike with the kids. She was planing on taking a shower. I got a little talking too..


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