[CaptainGizmo]

I've been in quite a few discussions regarding the water system in the modern coaches; referring to the 201x on.

Does anyone know of a schematic/diagram/layout that details the flow of water, the checkvalves, Headhunter, City supply, etc?

The big "mystery" is the interaction with city water, pressure differential, and how the water is taken from the tank vs. the city supply. Some would argue that, if you reduce the pressure of the city supply, through a regulator, that you force the supply to be taken from the TANK. Whereas, conversely, if you feed the coach with higher pressure, the system will draw its supply only from the CITY.

From what others have gathered, even if you ask 10 guys at Newell, you'll get 10 different answers!
   
So, I've taken a stab at it by labeling my system. The secret lies in this magic silver manifold!

Let's solve the mystery!

[RobSC]

Steve,

It's my understanding if the city water pressure is greater than about 40 psi, then it will supply water to the coach.  If that pressure drops below 40, then the HeadHunter water pump will kick in and draw water from the tank.  The HeadHunter will run until it reaches about 65 psi and then shut off.  Looking at your attached photo, my coach seems to plumbed the same as yours.

[hypoxia]

Methinks the "Mystery Bypass" is just a manifold.  The brass fitting on the left side of it is a check valve to prevent backflow to the 12VDC pump.  Good chance the check valve is seized with deposits.  You can disconnect the hose going to it & see if water flows from the check valve.  That valve is spring loaded with a snap ring.  You can remove it, take it apart to soak it in vinegar, replace the "O" ring and make it like new again.

[arcticdude]

If you think your check valve is giving you problems, they’re a common plumbing part available everyplace. Size is really the only option.

If you’re actively using your coach, it would be easy to swap one out. Then clean the take-out unit to use for the next time.

[CaptainGizmo]

Thanks, guys. I'm in agreement with ya'll.

Fact is, another Newell buddy and I have had a long, on-going, discussion over the pressure gradient issue. He's had a very good theory in which is convinced is how his coach works. And that is, he purposely uses a regulator at the post set to VERY LOW pressure; say 15-20 pounds. This has a number of benefits which, again, I can't argue against. They are:

1. He leaves his Auto-Fill On.
2. Water is ALWAYS coming from tank; thus keeping the tank water turned over and not go stale.
3. A consistent pressure, thanks to always depending on the pump. (I challenge this one, since the Pressure Pot has a definitely "range" it will assist with and causes a big drop in pressure before the pump kicks in.)
4. In the colder months, using "warmed" tank water can be a real benefit to give the Aqua-hot less work to keep up with high demands, aka wifey taking long showers, doin' the laundry, etc. ;-)

My curiosity is at play, now, cuz Jim, if you're right...and that chunk of aluminum is just that, then the PRESSURE-STAT is in the HH pump. So, as long as that city pressure is above that stat, the HH won't come on, and the water will just charge the Pressure Pot. If, OTOH, it's lower, then the city water will just stay where it is or go into the tank if the Auto Fill Valve is open.

I've never really dug into this with our coach since I always control my fill, and purposely turn it off so I know I'm using tank water...by watching the gauge go down. That's just MY way of positive reinforcement I guess.

Oooh, the things that make our minds spin at night.  LOL