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black tank flush port

andybren
Explorer
Explorer
I have a 2008 coachman Pathfinder diesel pusher which has a hose connection in the wet bay for a black tank flush. My question is ; do my other valves in the wet bay need to be in a particular configuration for the water to actually get into the black tank and do its job? No information is posted in the bay other than the one that says to open black tank drain before turning on the water.
6 REPLIES 6

way2roll
Nomad III
Nomad III
wa8yxm wrote:
As the first reply said the tank flush line is 100% independent of all other plumbing. And in fact I suggest even using a different hose to feed it. and when not pushing water into the tank DISCONNECT it.

There are safety devices to prevent backflow from Tank to the water system. Mine has both a spring check valve at the tank and a vacuum breaker above the tank... BUT even with Belt and suspenders you can lose your trousers. (Thus I "Air gap" the line to insure no possible backflow.


I literally have a brown colored hose for the black tank flush. That's all it's used for.
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Executive45
Explorer III
Explorer III
I forgot mine once and had water coming out of the roof vent. 2 hours later after washing the coach and surrounding area, I vowed never to forget to open the valve while flushing...Dennis
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wa8yxm
Explorer III
Explorer III
As the first reply said the tank flush line is 100% independent of all other plumbing. And in fact I suggest even using a different hose to feed it. and when not pushing water into the tank DISCONNECT it.

There are safety devices to prevent backflow from Tank to the water system. Mine has both a spring check valve at the tank and a vacuum breaker above the tank... BUT even with Belt and suspenders you can lose your trousers. (Thus I "Air gap" the line to insure no possible backflow.
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Old-Biscuit
Explorer
Explorer
If you haven't used it you should fist locate the Anti-Siphon Backflow Preventer device
It is installed at least 2' above black tank...typically inside bathroom sink cabinet
It acts like a check valve when water supply is turned off...allows air to enter tank side line so water drains back into tank
When water supply is ON the disc is pushed up blocking the air inlets
If it doesn't seal off...water POURS out and can flood bathroom etc

Water supply goes in bottom connection and flows to tank nozzle out the side connection

Someone should watch it when first using to make sure it doesn't leak



Cheap plastic ones are typical...better brass ones are available


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Edd505
Explorer
Explorer
You can close the valve while flushing, you will put approx 5 gallons a minute into the tank. Open & refill as needed until the tank waters running clear. DO NOT GET DISTRACTED, that can lead to serious damage. Keep the black closed except dumping or flushing.
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navigator2346
Explorer
Explorer
The black tank sprayer is totally independent of anything else in the bay. From the female hose connector, there should be a back flow preventer valve and then pipe to the sprayer. It is wise to open the black valve just in case you forget you are flushing the tank to keep it from overflowing