Using all the FW tank capacity

Formulaone · 07-09-2019, 09:51 AM

I have a Jayco Octane T26Y Toy Hauler (2016). My family and I had a heavier usage of the FW tank this past weekend and ran into an interesting issue. We filled up about 2/3 full (~65 gallons) and on the 3rd day of use the water started sputtering with air mixed in. I checked underneath the trailer visually and saw that the tanks had about 1/4 tank left in both tanks - plenty of water. I thought maybe it was because I had the overflow drains shut (I put valves on them because a lot of water had sloshed out of them on my first ever trip with my TT) and perhaps was creating a suction effect keeping water from flowing into the feed line to the water pump).

I opened up the drains and it did help, we got more water this time but still a lot of sputtering and you could hear the water pump running constantly. When I shut off the water pump there was air pressure built into the system and water would come out of the faucets if I used them.

We're home now and the water is running okay with some air in them and the pump will run continuously if I leave it on (I don't, I turn it off).

Shouldn't the water feed be able to use most of the water without sucking air? Am I doing something incorrectly?

RogerR · 07-09-2019, 11:28 AM

If I understand you saying air in the water when the pump runs then you have a leak at a fitting or cracked pipe that lets a little air in.

Mine comes up out of the top of the tank, bends over and goes through the floor then back up by the pump.

I would start at the pump and work back to the tank looking for somewhere it could be air could be coming in. Any loose fittings, cracks in the filter or back-flow valve, pump housing? Stress marks in the pipe, wet spots where tiny leaks have occurred?

If you still can't find it try filling the tank all the way up to get some pressure on a hidden spot to make it leak water out when the pump is off.

Formulaone · 07-09-2019, 12:26 PM

No, it's not that air gets into the system when the pump runs. When the tank was filled I had no problem with the water - it comes out fine, the pump only runs for an instant to pressurize the lines and only comes on when we use water. Once our water tank got down to approx. 1/4 tank it started blowing intermittent air and water as if the water pickup was at the water line rather than the bottom of the tank and sucking in a mix of water and air.

Camper_bob · 07-09-2019, 12:37 PM

I had a similar problem with my TT. It had 2x40 gallon tanks tied together. The "pickup" for the water pump was plumbed into the very bottom of each tank and tied into one line that went up to the pump.

Best I could figure was that it needed a little pressure to work right, and there just wasn't enough when the tank(s) got low. So I just never counted on that last bit of water to be fully available and just made sure I had enough in there for what I needed to do.

But we hardly ever boondocked with that rig, so I rarely needed ALL of my water.

New MH has similar issues but not as bad, and we DO boondock frequently with this one. By "not as bad" I mean there's just a few gallons in the tank we don't have access to.

RogerR · 07-09-2019, 12:58 PM

As above my water outlet from the tank is not all the way to the bottom. But I only have a small amount left in the tank when the pump pulls air, maybe 5% left.

When you get the air coming in it may be that the pickup is mounted to high in the tank. Maybe the installer got lazy and bored the hole to high. If that is the problem and you can get to it you can add a new tap close to the bottom.

Alternatively, as you get lower in the tank, the internal gravity feed may not be enough to overcome a tiny air leak. Try inspecting the tank to see if water is covering the outlet when it sucks air. If so, you must have a leak.

Formulaone · 07-12-2019, 07:29 AM

Looks like it's the inlet as you guys say...it's plumbed on the side of the rear tank and because it seems that I will have to level the RV so that it tilts ever so slightly towards that intake so that we can get most of the water. It's at the left rear of the rear tank and the way the tanks sit in the frame the front tank has a higher water level than the rear tank.

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