Weird Behavior with City Water

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Ex-Calif

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Joined
May 15, 2020
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Location
NorthCentral Florida
So the PO had modified the water system to permanently hook up to city water - I am not sure what he did or what he added but there is a pipe marked "drain" near the side of the cabinet with an extension on it and a stainless fitting that looks like a hose connection at the end - Could he have been filling through a drain? My book does not reference this drain and has two drains marked "lowpoint drains" near the knife valves and city valve. Although part of this "drain" is the same PVC as the rest of the system and the label "appears" to look like factory - picture below.

I have turned the 1/4 turn "city valve" horizontal and filled and drained tanks and black and grey tanks. So far I have operated on tank water and water pump.

Yesterday I hooked up a regulator with a pressure gauge on it, "closed" the city water valve so it isn't filling the tank and turned on the garden hose.

Water was spewing out of the sewer pipe with the knife valves closed - the pressure was in the "green" so I don't think it was over pressurized. I went inside to make sure water wasn't spraying around inside (LOL) and it wasn't. I opened the sink taps and water pressure was "higher" than pump but not like "house" pressure.

I left the taps on and went outside again and water was still "gushing" out of the sewer pipe. I then started worrying about overflowing the black or grey tanks so I shut the water off - I opened the knife valves and I can't remember but it seemed there was a lot of water built up in the grey tank.

I should note that I started with both tanks empty so the grey tank was filling fast.

Any ideas? Did I do something wrong or did the PO's mods likely have something to do with this?

For my maiden trip (starting tomorrow) I will fill and pump until after the trip and I can troubleshoot this further.
 

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I have no idea what they did but the Factory water inlet is where there is a pressure gage. The two side by side valves should be your low point drains. You say water runs out the sewer pipe means either the drain valve for the gray tank is not shutting all the way or you have a Tank drain valve still open.
 
Yes - the city fill is the one I have been using with the gauge on it. The city valve is in the "closed" position isolating the water tank from filling.

The black knife valve is visible and the grey valve is hidden in the first photo behind the sewer pipe.

The weird one is the other 2 pictures - not reference in my book. There is a gate valve on it. Water does not flow aout of this with city water dosconnected - i.e. it is not a drain.  I did not check if this is pressurized with the city water hooked up and turned on.

But for sure the knife valves were closed and water was gushing out past them. So somehow the grey tank is getting pressurized?
 
How many gray tanks do you have? Sounds like you may have a second gray tank like most of us do and that drain valve may be open.
 
Rene T said:
How many gray tanks do you have? Sounds like you may have a second gray tank like most of us do and that drain valve may be open.

I guess that is remotely possible but there are no other knife valves I have found. The shower/vanity is on the opposite side of the couch and I presume it is factory plumbed to the grey which is directly below the sink which is forward of the head.  The black tank is directly below the head. Both tanks are visible from the compartment.

Would that explain why the grey tank(s) are pressurizing?
 
A Georgie Boy Pursuit, like most motorhomes, only has one grey tank. The drain with the red hose attached looks like it's probably the fresh water tank overflow and drain. The lower horizontal pipe at the 'T' should have a valve for draining the tank somewhere, possibly close to the tank. The PO might have used the braided extension to back fill the fresh tank, but that isn't necessary as you know. The grey tank filling suggests there's a faucet or valve open that's allowing water to drain into the grey tank. The tank should not be able to pressurize since it's vented to the roof. Without tracing through the plumbing though, it's hard to guess what modifications a previous owner might have made and why. Permanently connecting to city water normally just involves hooking up a hose from the source to the inlet that's also used to fill the tank depending on the valve position.
 
NY_Dutch said:
Without tracing through the plumbing though, it's hard to guess what modifications a previous owner might have made and why. Permanently connecting to city water normally just involves hooking up a hose from the source to the inlet that's also used to fill the tank depending on the valve position.

Thanks Dutch...  It's nice to know I am not doing it wrong. Now when I get back I can dig in and see what he might have done.  I took a cursory look and the red hose he hooked up looks like it might trace to the top of the grey tank indicating a grey tank overflow? Anyhoo.  I can live with it for the next 10 days or so.

Today is launch day...
 
You need to find out what that extra "drain hose" drains.  Given the red pex and the stainless steel hose, I'm wondering if it is maybe a connected to the water heater tank?  Intended to hook to a hose, so that hot water could be used somewhere else, perhaps?  Since water was not gushing out of that fitting, it appears there is a valve somewhere that controls it. Need to find that and see what it does.


Your other problem, water entering the grey tank, indicates that somewhere there is a connection between the fresh lines and the grey waste that lets fresh water flow into the waste drain.  Are you sure that happens only when the city inlet is used?  The city inlet normally is just a Tee off the fresh line, same as the water pump. Both feed the same fresh water lines and can both be active at the same time.  Regardless of whether the water enters from the city inlet or the pump, it should behave the same way. If water can move from the fesh lines to the grey waste in with city-hose as the source, it should be the same with the pump as the source.

Water pressure in the system should be whatever is present at the city inlet (as provided by the source); it may be more or less than what the pump produces. Usually more, but not always.
 
If you look closely at the center photo, there's a 'T' in the line marked "Drain Outlet" that the red hose has been attached to. I suspect that line originally passed through the bottom of the bin to drain out side. The only reason it might run to the top of the grey tank that I can think of would be a jury rigged tank flush setup. I think it more likely that horizontal leg of the 'T' goes to a valve and then connects to the bottom of the fresh tank. The upper vertical leg would then go to the top of the fresh tank to serve as an overflow.
 
Wish I was near Ohio - this sounds like an interesting one.  The only thing I keep thinking is that there would be no reason for the PO to "modify" it to only work with shore water unless there was a problem.  I don't think this is a common modification.

 
The only thing I keep thinking is that there would be no reason for the PO to "modify" it to only work with shore water unless there was a problem.
Yeah, I was thinking the same thing. The water system basic design inherently works with city water, so I cannot think of anything to modification that would help in any way.  However, I have seen a mod that added a second water source and delivered non-potable water to some of the faucets, basically so that the toilet and shower could use non-potable water while the good potable stuff was reserved for the galley sink. Essentially the mod was to divide it into two separate systems, one for potable water (from the pump/tank) and the other non-potable.  That could conceivably be the case here.
 
I think the key is the red line that is connected to PVC marked "drain"- Why would this have a hose connection?  If I am thinking right that this is an "overflow drain for the grey tank then some how the system might be filling the grey tank via the "overflow" - Who knows (yet?)

I have made it safely to Biloxi, MS. on my maiden voyage so will look a this all when I get back...

This week is R&R! Crowded as heck here along Biloxi beach.  The last 2 miles took over an hour.  The last 300 feet to the turn in literally took 15 minutes...

 

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I can see a reason for adding a secondary drain for the gray tank, though.  I used to camp occasionally where there was a dry well for gray waste water and thought about adding a water hose connection to the gray tank every time I used it. That's a more convenient solution than an adapter cap on the big main drain pipe.
 
Mystery (not) solved...

I poked around a little this morning - I had not hooked up water last night - I didn't do anything positive but when I hooked up the water it appears to be working fine.  Pressure at the taps (pump off) and no flow out the drains.

The RV sat for 3 years before I bought it.  I filled and sanitized the water tank like three times.  I filled the grey water to 2 out of 3 bars.  There was "dry" chemical stopping up the head that I chipped out and cleaned.  Water flowed well into the black tank and I ran about 10 gallons in and then drained it and it drained properly enough.

I am wondering if there weren't/aren't caked in solids still in the black tank - it seems to fill "fast" like 10 gallons puts the 2/3 light on and it should be a 40 gallone tank.  I will continue to put "extra" sanitizing chemical in this week and doing "extra" flush when I flush.  Maybe there are things that will work lose over the next 7 days.

So still learning and as we say in the middle, "Even a blind pig finds an acorn once in a while..."

I am not complaining - LOL...
 
For the trip home, perhaps add some ?Dawn? and a bunch of water to the black tank? The agitating action while driving may loosen things up?

Glad you are having fun. How is the camp site? Looks convenient to the water.

Is the Biloxi waterfront crowded?
 
Lynx0849 said:
For the trip home, perhaps add some ?Dawn? and a bunch of water to the black tank? The agitating action while driving may loosen things up?

Glad you are having fun. How is the camp site? Looks convenient to the water.

Is the Biloxi waterfront crowded?

Check out my trip post here - http://www.rvforum.net/SMF_forum/index.php/topic,128008.msg1172608.html#msg1172608
 
If the RV is going to be sitting for  few weeks when you get home, add water and some Rid-X to the black tank. The bacterial enzymes in Rid-X may loosen up any remaining waste material enough to let it flush out.
 
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