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mrk 03-28-2016 01:19 PM

Water disappears from fresh water tanks
 
We've noticed that our 90 gallons of fresh water doesn't last very long, regardless how little of it we use. Usually I'm down to the lowest water level indicator light in about 3 days, and we haven't used all that much water. We even tried turning on the water pump only when we need water, but this hasn't helped. Then we noticed that I'd leave a stream of water when I make a turn when leaving a campsite or make a turn onto the road. It seems to come from under the left side, but we don't know exactly where it comes from.

I was sure that I had a ruptured water tank from overfilling it, but I just pulled both tanks and cannot find any indication of a rupture or other leak around the connections. In fact, the floor under than tanks is nice and dry with no indication of any water.

Might the hose from the tanks to the water pump have a break in it wand be siphoning the water from the tanks? Has anyone tackled replacing the water line/hose from the water pump suction side to the water tanks? Where is the line routed? Is there a "low point" where the hose dips below bottom of the water tanks?

Dale
MrK

wb7auk 03-28-2016 02:03 PM

What is happening is the vent hose from the tanks is siphoning your water out on the ground. I have installed a valve in mine so I can select vent or closed to cure this problem just make sure you switch to vent when filling or drawing water once you are parked.

mrk 03-28-2016 08:27 PM

Quote:

Originally Posted by wb7auk (Post 2997354)
What is happening is the vent hose from the tanks is siphoning your water out on the ground. I have installed a valve in mine so I can select vent or closed to cure this problem just make sure you switch to vent when filling or drawing water once you are parked.

Hi Art. Thanks for your input. At this point, I can't rule out anything, but I guess I don't understand how the vent hose, which is on top of the tanks, can siphon water, unless the water tank is slanted so that the vent is below the level of the water. Otherwise, I can't see any way the water could get to the vent hose. I have seen posts by others who have put a valve in their vent hose, but I presumed that was to keep anything from entering the hose from the outside.
Tonight we hooked a water hose to the end of the fill hose at the location where it would be attached to the tanks. I guess we were back-feeding the water system. We did this to see if we could see any leaks would become evident, or if we could hear any water leaking. We did find a leak near the water pump on the discharge side and a couple of others in the wet bay area. I suspect this may be because the land-line water pressure is excessive. We also found out that my 1999 Tradewinds doesn't have the water pressure regulator built into the wet bay area. Of course, the water pump is at about the right level for siphoning to occur.
Tomorrow I will double check the fittings on the water tanks and re-install them. I'll fill them and sanitize them, and see what happens.
Dale

wb7auk 03-28-2016 09:19 PM

All I can tell you is every 1999 tradewind I know of unless the vent valve has been put in or the vent hose put higher will siphon the water tank down to just a little over 1/3 to 1/4 tank.
I did not pull the tanks and see what caused it.
I installed a two way valve in the water bay and plumbed the hoses to it and hoses to the outside and problem taken care of unless I forget and do not close the valve before I get underway which in time empties the tanks.

By all means put in a water pressure regulator will save your water system.

chboone 03-28-2016 11:19 PM

I have the same problem with the vent lines siphoning water from the tanks. Another thing I found is the line between the two tanks is small and takes a while to equalize the level in both tanks. When filling the tanks as soon as I see water trickle from the vent of one tank I shut off the water. Then wait for 10 or 15 minutes and start the water fill again. I do that cycle until I see water from the vent line as soon as I turn on the fill water, then I know both my tanks are full. If I don't do the fill that way and check my tanks later they will only show 2/3 - 3/4 full. My Dolphin fresh water tanks are behind the drive axle, I found that raising rear up with the jacks helps to prevents the siphoning when filling.

wb7auk 03-29-2016 07:00 AM

One would think a vent can not siphone but there has to be something done wrong in these MH's but when one finds a large number of the same units with this common problem something is amist.
If I fill the tanks full until the water comes out the vent hose and shut the fill hose off water will continue coming out the vent hoses until the tank is almost empty.
Or while driving if the vent hose starts to dump water for what ever reason it will
almost empty the tanks. My cure was a control valve on the vent lines.

Bigd9 03-29-2016 07:47 AM

Quote:

Originally Posted by mrk (Post 2997307)
We've noticed that our 90 gallons of fresh water doesn't last very long, regardless how little of it we use. Usually I'm down to the lowest water level indicator light in about 3 days, and we haven't used all that much water. We even tried turning on the water pump only when we need water, but this hasn't helped. Then we noticed that I'd leave a stream of water when I make a turn when leaving a campsite or make a turn onto the road. It seems to come from under the left side, but we don't know exactly where it comes from.

I was sure that I had a ruptured water tank from overfilling it, but I just pulled both tanks and cannot find any indication of a rupture or other leak around the connections. In fact, the floor under than tanks is nice and dry with no indication of any water.

Might the hose from the tanks to the water pump have a break in it wand be siphoning the water from the tanks? Has anyone tackled replacing the water line/hose from the water pump suction side to the water tanks? Where is the line routed? Is there a "low point" where the hose dips below bottom of the water tanks?

Dale
MrK

When dry camping we can usually plan on our fresh water to last 3 days, 5 days if we are very careful.

90 gallons in 3 days is only 30 gallons per day. If two people are using water doing the dishes, bathing, flushing the toilet etc. that is 15 gallons per person. Not all that much water at all. And if your level indicator is like ours, even if reading empty, there is still water left. On my coach, the first water level probe is located at the 1/4 mark. So when the water level drops below this probe, the indicator shows empty. BUT there is approximately 1/4 of the water left.

Quote:

We even tried turning on the water pump only when we need water, but this hasn't helped.
Not sure why you are doing this. Is the water pump running or cycling even if you are not using any water in the RV?

mrk 03-29-2016 10:05 AM

Pete, maybe you've found my problem, or at least, a portion of it. Maybe my usage exceeds what I think I'm using. But honestly, I suspect that can only a part of the problem, as on my last trip last fall, we filled the tanks at the campsite on Thursday afternoon, and by Sunday morning, we were nearly out of water. Sponge baths only, minimal dish washing. My wife does accuse me of washing my hands too much though!
I shut off the pump, just in case there was a leak somewhere, and I didn't want it to keep pumping water while we were gone for the day. Yes, the pump does come on for a short burst every once in a while, but not very often.

I rarely drive with more than a half tank of water, but if the tank were full, I could see it losing some water through the venting tube, simply as a result of going up and down hills. If one drove a 6% uphill grade all day, then I could see the tanks draining down to just over one-half full. Since the vent tube is on top of the tanks and does not go down below the upper surface of the tanks, I cannot envision the ability to siphon from the top, just the ability to drain.
I think Art hit the nail on the head: to prevent siphoning/draining of the unlevel tanks, raise the height of the vent tube. My guess is that 3-4 inches of additional height would cure 99% of the problem without the need for a shutoff valve.
Still, I wonder where the water came from that was draining from beneath my TW as I was making turns. (It had rained, so maybe I've got a leak.)

I originally asked if anyone knew if the water hose from the water bay to the tanks drops below the level of the water tanks. If I want to examine that hose, where would I find it?
Thanks for all your valuable input. As said before, I'm not discounting anything at this point.
Dale


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