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Old 01-04-2019, 10:18 AM   #1
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Join Date: Jan 2019
Posts: 1
Water problem

My cardinal 3550 has a water problem. WhenI I hook up to city water it back flows somehow into my fresh water tank and overflows,

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Old 01-04-2019, 10:29 AM   #2
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Join Date: Dec 2017
Posts: 799
Common issue. The key thing is to relieve the pressure before switching to pump. Here is a fix that was posted here before and worked for me.

-Open any faucet to drop pressure to zero (no water flow)
-Turn on water pump
allow water to flow for a minute or so then shut off open faucet
-Once the pump stops, turn off water pump
-Turn city water back on.

This will reseat the back flow valve and 90% of the time corrects the problem. Once corrected, drain the FW tank unless you plan to use it.

-Alternate Turnoff the city water, with the pump off open a faucet to relieve pressure, then close the faucet and and open the city water valve. The city water pressure can seat the check valve better with no pressure behind it.

If this doesn’t work for you search for fresh water tank overflowing on the forum

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Old 01-04-2019, 10:32 AM   #3
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Join Date: Jun 2012
Posts: 10,907
Common problem. The check valve on your water pump is leaking, allowing city water to backflow through the pump into the fresh water tank.

Usual fix:

Turn off city water. Turn on water pump. Open a faucet and allow the pump to pump water for a minute or so. This will flush out the check valve. Close faucet, turn off pump, turn city water back on.

This usually solves the problem. If not, the check valve may be damaged. Fix then is to either replace the check valve (the valve is usually internal to the pump) or add an external check valve.

See attached generic plumbing pic.
Attached Files
File Type: pdf RV Plumbing pic.pdf (125.1 KB, 14 views)
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