Water going to Gray tank with pump on 2013 Minnie TT

[Big Roy]

I am new to travel trailers and this site. I recently bought a 2013 Minnie Winnebago Travel trailer. Looks like it has had little use. I used it last week and discovered when the water pump is turned on or the water hose is connected water is flowing into the gray tank. All faucets are turned off at this time.
I have looked for open drain valves but found nothing.
I do have a mechanical background, but campers are a learning curve for me.
Any help will be greatly appreciated

[Morich]

So what are the signs that you find showing this happens?
It's not possible to have an RV built that way for a number of really good reasons. Some are the health/safety regs but then there are also the physical problems of getting materials to connect fresh water lines to waste lines.
It can be done but it would take a major dummy and special effort and parts to do it!

If it is not a sneaky stool leak, there may be things like tank readings, etc, that are confusing the issue.
Can you tell us more about what appears to be happening and when?

[Big Roy]

When I turned the water pump on the pressure and flow were very good. Forgot to turn it off for a half hour. I had drained the gray tank before leaving home so I knew it was empty. Turned the pump off for an hour. then turned it back on. Started to take a shower and no water?!
Shortly after I was scratching my head and decided to crack the valve on the gray tank. Good thing I was on a private river area for the tank was full of the clean water from the freshly filled supply tank.
Gave up on the water for the weekend.
Earlier today I Hooked a hose from my well (with a 40 lb. pressure regulator attached) to the supply port. Checked that all the faucets were off, opened the drain for the gray tank, turned the hose on and stood back. Within a couple of minutes water started out of the gray tank discharge.
A I said I just bought this trailer. I do not know the full history or have manuals for anything. I will be crawling under it tomorrow to see what I can discover there.
Thankyou for your time and interest.

[creativepart]

This is very very very odd and as Richard said... they don't build any RV with a connection between fresh tank and gray tank.

Since it's new to you all bets are off.

[Morich]

Ok, so there is a mystery going on and it needs checking!

One way to avoid some confusion is to look at smaller parts of the big puzzzle. One way to do that is to look at only the pressure water or the pump at a time. In this case I would suggest looking at the pressure system first if you a place to connect.
It has fewer items to mess with our minds!

Connect to the RV and turn the hose faucet on and we can be pretty sure we are getting water to the RV! I might start with all the inside faucets closed and all the drains I knew about also closed.

That should make it all just set there and no water should move!
If you have enough water moving in the hose, you may feel it and then you will need to look for where it is going!

One point to try to verify is a valve to set if you are filling the fresh water or if it is set for normal RV use. Different RV use different ways to make this choice. If you have this valve and it is not fully set for normal use, water can pass to the fresh water tank.
At this point, I would leave the fresh tank empty if it is now as a way to help locate where any water comes from, if you find what might look like a leak.
If no water in the tank, alll water has to come from the hose not at a leaking tank,etc.

[Big Roy]

Thank you for the sound advice! I am a retired factory Maintenace man so have experience with problems. You have pointed out a sound path to follow.
The freshwater tank is currently empty. I will continue to look at the full system. Did find the water heater was set for bypass today. Finally found all the components (I think).
I was wondering if there was a drain valve somewhere I was overlooking!
This trailer has separate points for filling fresh water and city water.
Thank you once again.
Roy

[Morich]

Ok, sounds like logic has a place in your experience!
One way to spot drains that may be hard to find is looking at the underside for tubes hanging down open at the end. That often means there is a valve almost directly above!
Traliers certainly don't get the best online posted info, so we have to look for ways to get around!

Just some points on the way RV water works may help to clear a few questions.
The pressure water is fairly straight forward as it comes in and connects to all the faucets, DUH!
point to notice is that there is likely a little spring loaded button inside the water fitting. That acts as a cheap once way( check) valve. It lets pressure water in but when we diconnect the hose and use the pump, we build pressure on the inside lines connected to that port. If we did not have a check valve there, water would come OUT instead of going in!
One to keep in mind because that little plastic disk can get broken or flip up on it's side and when you turn on the pump, water may trickle down the side!

But then when we look at drawings online for the motorized group, we can see that pressure water going in and meeting the line from the pump doesn't go through the pump backwards to the fresh tank! There is a check valve built in the fresh pump to keep water flowing backwards into the tank to overflow!

Simple things like check valves solve some big questions. How do we put pressure on from a hose but not fill the tank if we also put pressure on with the pump?
I drew up this crude drawing. you know one way valves (check ) valves?
Two simple ones involved to stop water going the wrong way to get outside or the other way to get to the tank and overflow it!

Click this to get better view!


Tricky little gizmos can be fun OR they can drive us silly if they feel like it!


You likely have one playing games with your mind!
Reason for thinking there is not much chance of any connection is the difference in pipe for supply and drains. supply is often 1/2 inch tubing and it's hard to get fittings to match it to 1 1/4 drains. It can be done but it takes effort!
Unless you are following a real bummer!

[Big Roy]

I found it!!! After extensive searching I found an after factory drain line. It was located behind the outdoor kitchen behind the floor panel.
I finally used a length of 7/16" plastic tubing to listen for water running. By inserting it slowly down each drain I was able to isolate the area of concern. Why a line had been added there beats me. It will be mentioned in past tense. I had a fitting that worked so pulled it out of the line. Used JB Marine Epoxy and a sheet of flexible plastic to cover the drainpipe hole they had added.
Here is a hearty thank you for the support and help with this problem!
Roy

[Bobn1957]

Originally Posted by Big Roy

I found it!!! After extensive searching I found an after factory drain line. It was located behind the outdoor kitchen behind the floor panel.
I finally used a length of 7/16" plastic tubing to listen for water running. By inserting it slowly down each drain I was able to isolate the area of concern. Why a line had been added there beats me. It will be mentioned in past tense. I had a fitting that worked so pulled it out of the line. Used JB Marine Epoxy and a sheet of flexible plastic to cover the drainpipe hole they had added.
Here is a hearty thank you for the support and help with this problem!
Roy

I wonder if the previous owner put that in to keep the drain from freezing! It might make sense if the unit was parked on a pad and used in the winter.

[Big Roy]

I never figured it out but I had a heck of a time finding it.
Think I pretty well know the plumbing now.
Roy

[Morich]

If they simply wanted to run water down the drain to avoid freezing, it seems much easier to just open a faucet and let it go down the drain as it does normally!
Making a bypass and not running it through the faucet would seem to be self defeating as the faucet and trap would then be prone to freeze damage!

Speaking of self defeating? Has anybody ever looked at how this part of the world builds houses? The standard is to not build them for winter then when it gets cold, you are told to drip faucets all night to run water down the drain!
Now during the summer we are told not to use water because the lakes are getting dry!

Must be the same folks doing your RV plan?

[Ray,IN]

Originally Posted by Morich

If they simply wanted to run water down the drain to avoid freezing, it seems much easier to just open a faucet and let it go down the drain as it does normally!
Making a bypass and not running it through the faucet would seem to be self defeating as the faucet and trap would then be prone to freeze damage!

Speaking of self defeating? Has anybody ever looked at how this part of the world builds houses? The standard is to not build them for winter then when it gets cold, you are told to drip faucets all night to run water down the drain!
Now during the summer we are told not to use water because the lakes are getting dry!

Must be the same folks doing your RV plan?

Totally illogical, it takes the same R-factor insulation to keep hot or cold inside the structure.
Don't outside kitchens have a drain line for the sink already? That add-on line sounds useless to me, unless the drain was freezing too.