Fresh water fill not venting -- Thor ACE

[EdInArk]

My Thor ACE has a gravity feed fresh water fill, and I'm having a venting problem. As I fill with a hose, the level comes to the top of the pipe. I stop filling, and it starts burping water back out as air bubbles come back up the pipe. I put about a gallon in, the pipe fills up, and I wait several seconds while several ounces regurgitate back out as it bubbles. When it settles down I can get 3/4 gallon or so in. I've worked on it the better part of two hours to get it 2/3 full. I'm in the process of sanitizing it, and it kills my soul to know I'm gonna have to drain and fill again.

There's a screened hole next to the fill pipe that I took to be the vent but I see no way to clean it. I'm thinking maybe I could pull that fitting off, and there may be a tube behind that screen that I could blow out with an air compressor.

Thoughts would be appreciated?

[60sumtin]

The fill hatch sounds like what I have, a capped fill hole beside the screened vent. With ours, because the air in tank is being displaced by the incoming water it can't exit fast enough thus builds up a bit of back pressure and eventually burps. The tank also balloons a bit as its filled. I just slow the flow down a bit when that happens and all is good for the last few gallons. The screened vent is just a small hose that goes to the top of the water tank.

If you have visual access to fill and vent tube check to see if maybe there is a kink in one or both of the hoses.

Edit, as for cleaning the vent try capping the fill tube quickly as it burps to allow the water and anything in the vent to be pushed outward. Using a wet cloth you could even try to make a seal around the fill hose forcing water up the vent tube rather than the fill tube. If there's anything in the vent tube blowing into it would push it into the tank.

[deboy69]

I took the vent line off the tank and blew in pressurized air and there was some mast gunk in it. Worked fine after that.

[EdInArk]

Originally Posted by 60sumtin

The fill hatch sounds like what I have, a capped fill hole beside the screened vent. With ours, because the air in tank is being displaced by the incoming water it can't exit fast enough thus builds up a bit of back pressure and eventually burps. The tank also balloons a bit as its filled. I just slow the flow down a bit when that happens and all is good for the last few gallons. The screened vent is just a small hose that goes to the top of the water tank.

If you have visual access to fill and vent tube check to see if maybe there is a kink in one or both of the hoses.

Edit, as for cleaning the vent try capping the fill tube quickly as it burps to allow the water and anything in the vent to be pushed outward. Using a wet cloth you could even try to make a seal around the fill hose forcing water up the vent tube rather than the fill tube. If there's anything in the vent tube blowing into it would push it into the tank.

I tried slowing it down. I even used a funnel and and gallon jug. Maybe if I slowed it to a trickle it'd vent fast enough, but it took me a couple of hours to get it 2/3 full. This is a new development as well. When we filled it a couple of months ago we just stuck a hose in it for a few minutes, and it was full.

I'll try again to find the bottom end of the vent, but I fear it's on top where I can't get to it.

Originally Posted by deboy69

I took the vent line off the tank and blew in pressurized air and there was some mast gunk in it. Worked fine after that.

Thanks. I'll try to find the vent.

[60sumtin]

Originally Posted by EdInArk

I'll try again to find the bottom end of the vent, but I fear it's on top where I can't get to it.



Thanks. I'll try to find the vent.

Yes it would have to be on top for it to vent the displaced air.

I just went out and took a close look at the screen on ours and it does appear to be partially restricted with what I'd call a fine fuzz. With a few bristles on paint brush I was able to push some of it away. Perhaps yours is the same or maybe something inside the tank that's been in there since new just happened to get pushed up into the vent tube during filling. If there was something in the fill tube one would think it would get flushed out during fill but who knows. As mentioned force air or water down the vent tube and see what happens.

[EdInArk]

Originally Posted by 60sumtin

Yes it would have to be on top for it to vent the displaced air.

I just went out and took a close look at the screen on ours and it does appear to be partially restricted with what I'd call a fine fuzz. With a few bristles on paint brush I was able to push some of it away. Perhaps yours is the same or maybe something inside the tank that's been in there since new just happened to get pushed up into the vent tube during filling. If there was something in the fill tube one would think it would get flushed out during fill but who knows. As mentioned force air or water down the vent tube and see what happens.

Obviously, it'd have to be on top, but I was sort of hoping it'd be on a top edge or something so I could find it.

The location of the screen makes it difficult to force anything down it. I'd considered pulling the fixture on the outside with the fill tube and screen to get to the vent tube. It seems like it should be pretty simple, but sometimes things just don't work that way.

It started storming yesterday and I came in. I'll look at it some more today.

Originally Posted by 60sumtin

Edit, as for cleaning the vent try capping the fill tube quickly as it burps to allow the water and anything in the vent to be pushed outward. Using a wet cloth you could even try to make a seal around the fill hose forcing water up the vent tube rather than the fill tube. If there's anything in the vent tube blowing into it would push it into the tank.

I've been thinking over this suggestion as well. I need to drain the bleach solution today then refill. It's raining now, but when it stops I'll see what I can do.

thx

[EdInArk]

Well, thank you both for brain storming with me. I attached a hose to the male end of a air fitting and stuck in in a small air compressor. The hose has a clean enough end and is just the right size to hold against the outside rim of the screened vent. I started with 0 psi in the compressor, held the hose to the vent, and turned it on. At about 3 psi it started gurgling water back out the fill pipe. Yeehaw!

All's good. I filled it again and could leave the hose wide open with no problems.

http://www.irv2.com/forums/attachmen...1&d=1527365510

[triplewide]

Glad you solved the problem. My vent hose became fouled with mold:

http://www.irv2.com/forums/f121/ace-...ml#post3321925

[EdInArk]

Originally Posted by triplewide

Glad you solved the problem. My vent hose became fouled with mold:

http://www.irv2.com/forums/f121/ace-...ml#post3321925

That's what I feared, and I couldn't get to it. I drained the tank the next morning with the cap on it, and I could hear it bubbling through that vent. Maybe that vacuum was enough to pull whatever was it in it back out. I blew it out anyway.

All's well that ends well.

[Maligator]

I had a similar problem but the problem with mine was that they left the clear vent tube a few inches too long at the factory which caused it to sag and allow water to get caught in the vent tube. This essentially made a P trap out of it and did not allow air to flow by which then caused it to burp while filling and making matters worse.

I simply trimmed the clear vent hose down at the tank end to eliminate the sag and problem never returned.

[EdInArk]

Originally Posted by Maligator

I had a similar problem but the problem with mine was that they left the clear vent tube a few inches too long at the factory which caused it to sag and allow water to get caught in the vent tube. This essentially made a P trap out of it and did not allow air to flow by which then caused it to burp while filling and making matters worse.

I simply trimmed the clear vent hose down at the tank end to eliminate the sag and problem never returned.

I think that's my problem as well. The tank is in the bedroom slide, but I can't get to the fill and vent tubes without more dismantling than I want to do. Being in the slide, there has to be some slack to allow it to move in and out with the slide. We actually had a P-trap in both the fill and vent tubes.

The last time it was at the shop the dealer filled it to the top; I removed the cap at home and water started trickling out. I THINK that's what caused the problem. That also filled the vent tube. Then as we used it the level dropped leaving the water in the tube as you've described.

I've told my wife that we shouldn't fill to overflowing. We don't boondock, so there's really no need. But I'll keep my highly-calibrated, custom-designed tool that I created .... just in case.