Water Inlet ID

[Ljwt330]

Originally Posted by GypsyR

Well when you changed it, it made more sense. Now we can assume the pump does not allow flow past it when you are using the pressurized tank fill B.
Now the filter bugs me though. A filter ahead of most any pump is a good idea as they generally don't like debris. But if you introduced debris through B when tank filling the not-a-checkvalve screen would catch it. But as soon as you turned to pump on it would then draw the debris back out of the screen and digest it.
I guess the thinking is you're a lot more likely to introduce acorns, insects, gravel, or whatever through the gravity fill than city water. Still odd that they wouldn't move it upstream one more slot and that way catch anything from all the incoming water there. You can ensure it never being a problem just by using a filter on the hose when you fill the city water. Which is what I always do anyway.

Should there be any debris in your freshwater hose or the city water? No. But there wasn't supposed to be a dead mouse inside the funnel I use to put oil in the engine either. If our water supply was always perfect all the way through we wouldn't ever need filters.

Note bold.


If his diagram is now correct and the photo correctly labeled, there is no pressurized tank fill available in his RV.


Port "B" is a suction port and line and yes, debris could be introduced into the system if the hose connected and the container from which it draws liquid is dirty. That's why I suspect it is for winterizing or emergency use from a portable water container. If doing so, it would be wise to have a screen/filter in place somewhere in the hose connection.


Given what you pointed out, there could be some havoc if pressurized water was forced through port "B". Yes, that filter does not look like a check valve and it could be compromised if pressurized water was present. However, it still may have a check valve inside, but one would have to look closely to know. If it is OEM, I would suspect it is a check valve, just to prevent such an occurrence.

[GypsyR]

I'm about to throw my hands up on this one. A "suction port"? How would you use that? park next to a full horse trough? A fish pond? I don't get it. The logic of this setup is eluding me either way to tell the truth.

[Ljwt330]

Originally Posted by GypsyR

I'm about to throw my hands up on this one. A "suction port"? How would you use that? park next to a full horse trough? A fish pond? I don't get it. The logic of this setup is eluding me either way to tell the truth.

LOL, I get the frustration. My answers are not definitive, just based on typical rv plumbing and information supplied by the OP.

Frankly, a suction line Teed in before the pump is common for adding antifreeze to a system and they are generally located where the OP shows the port “B” line. What is different about this is the size of the line and that it has a hose connection. Most antifreeze lines are small diameter vinyl tubing with a shut off valve to seal the line when not in use. Because the line is large and has a hose connection, the guess is it is also for getting water from a portable container, given this is on a trailer which is more likely to be boondocking.

Regardless, the location of the line dictates that the pump will pull fluid through it. Why would the rv builder have two pressurized city water ports? Why would a manufacturer not include a way to winterize the system? Many state and local parks do not have hose bibs at the sites for hooking up, only to access potable water into a container. The water must then be poured into the gravity fill, or pumped in through port “B.”

Still, i have not seen such a set up. I suppose you could fill the tank by pressurizing the port “B” connection, shutting off all interior faucets, and forcing all water through the filter and into the tank. That, of course, would push all the debris in the filter back into the tank as well. That design, to me at least, is not logical.

[Old-Biscuit]

'A' is the Normal City Water Inlet....connects with pump discharge and supplies the RV Plumbing System

'B' is a 'winterizing' suction connection
Attach a short garden hose to connection...sticj the other end of that short hose into a bottle of anti-freeze and turn pump ON
Pump sucks up the anti-freeze and pumps it into RV Plumbing System
**what is suprising is there is no shutoff valve...it should be sucking air in when pump runs

***hookup/turning on a Pressurized hose would NOT be good idea...tough on pump drive diaphagrams and strainer backflowing into tank
'B' Should only be used to SUCK water/bleach soultion or anti-freeze IN

[r___r]

Once I reviewed, examined the details of the plumbing, and re-labeled the picture, I was able to draw the diagram correctly. I feel like a dummy that I, previously didn't see and catch the details more closely, I just saw the two white hoses and didn't see the gray poly line as part of the input lines from the outside of the rv.

After my last post, all of your posts have have helped me understand the RV plumbing a little better.

Thank you ALL for chiming in with all your thoughts and knowledge on this thread. I appreciate it.

Safe travels to you,

Rich

[Argosy]

Originally Posted by Old-Biscuit

**what is suprising is there is no shutoff valve...it should be sucking air in when pump runs

There might be. The T isn't a standard plumbing T, the diameter is too big, it's cast flat sided brass (which means the expense of machining), and the third inlet is offset to the right. It also looks like there's a handle for a valve on the backside. One way water flows through from the freshwater tank, turn it 90º and it draws from the antifreeze bottle.

[GypsyR]

A secret hidden valve? NOW things are starting to add up!

[Old-Biscuit]

Originally Posted by Argosy

There might be. The T isn't a standard plumbing T, the diameter is too big, it's cast flat sided brass (which means the expense of machining), and the third inlet is offset to the right. It also looks like there's a handle for a valve on the backside. One way water flows through from the freshwater tank, turn it 90º and it draws from the antifreeze bottle.

Originally Posted by GypsyR

A secret hidden valve? NOW things are starting to add up!

Good catch!

Makes sense......with shutoff valve definitely for 'winterizing'

[Ljwt330]

Originally Posted by Argosy

There might be. The T isn't a standard plumbing T, the diameter is too big, it's cast flat sided brass (which means the expense of machining), and the third inlet is offset to the right. It also looks like there's a handle for a valve on the backside. One way water flows through from the freshwater tank, turn it 90º and it draws from the antifreeze bottle.

Originally Posted by GypsyR

A secret hidden valve? NOW things are starting to add up!

Good catch, Argosy.


Looking closely again at the photo and I agree that there appears to be a valve knob facing away from the camera. It looks to be turned so the valve would be opening flow directly from the fresh tank.

As GypsyR stated, things are starting to add up! That valve explains everything. It allows water from the fresh tank through to the pump, or it closes access to the fresh tank and opens to the suction line from port "B". It's a "one or the other" situation. It also explains why no air will be sucked into the system should the owner forget to cap the "B" port.

[GypsyR]

I had to flip back to the original pictures to look. SHARP eyes Argosy has!

[Argosy]

I like vintage everything so I've learned to look really hard to understand how they work.

When Old-Biscuit said he wondered why the pump wasn't sucking air I'd wondered the same thing, that prodded me into looking at the T more closely, which I originally thought looked like a check valve and saw that little bit of the handle, then the tang for the stop on the other side of the compression nut and knew it was actually a ball valve. The OP's phone/camera helped a lot, it takes really clear pictures.

[r___r]

Argosy,
If you hadn't seen that valve from that angle, I would still not understand why the Inlet 'B'.

And with all the info shared from ALL on this thread, I thank you.