Air blockage in my water tank?

[Patrick Broderick]

Lately I've beenn having trouble filling my water tank. It will take the water for 15-20 seconds and then belch out a bunch of air. I can't seem to get any water in because it continues to belch out air every few seconds. I'm not sure what's going on, it didn't behave this way before but now does all the time. Does anyone know how to vent the air?

[Kirk W]

It probably has a vent tube that has somehow become blocked. That sort of thing can happen if the vent line has a place that sags down somewhere that could trap water and the tank gets overfilled. If that happens the low point can make a water trap just like the "P" trap does for a sink drain. Problem is that the trap is designed to stop air from leaving the drains and it does prevent venting action. 

[Patrick Broderick]

Any suggestion as how to get the water out? A blast with pressurized air or CO2 perhaps?

 

[Alie&Jim's Carrilite]

Pic of the fill port/connection might help us.  Is it a hose connection where you turn a valve to allow water into the tank, or is it a port where you put the hose end in and let it run.  

Also is it a coach, 5th wheel, travel trailer, model and make? Someone here will probably know what's going on with a little more info.

[mptjelgin]

I've found that a few inches of water in a low point of the vent hose won't be a problem. The pressure of filling your tank will easily push the air right through that. You'll hear bubbling and burbling but there shouldn't be much resistance. I'd suspect something more solid may have plugged your vent.

You should be able to find the outlet for the vent, which is usually a 1/2" (ish) hole next to your hose fill fitting (assuming you have one). You may be able to flush back from that point, but realize you'll be pushing whatever is plugging the vent back into your fresh water tank. So once you get the blockage cleared you may want to drain and then sanitize your tank. 

[ALLOY]

A vacuum on the vent hose?

***Makes sure the FILLER cap is off or you'll CRUSH the tank****

 

 

 

 

[Patrick Broderick]

2 hours ago, Alie&Jim's Carrilite said:

Pic of the fill port/connection might help us.  Is it a hose connection where you turn a valve to allow water into the tank, or is it a port where you put the hose end in and let it run.  

Also is it a coach, 5th wheel, travel trailer, model and make? Someone here will probably know what's going on with a little more info.

It's the latter, I have a 1988 Tioga Mobile Home (Coach, I guess) which has a screw off cap that you just insert a hose and fill up from there. I also have a place where you screw the hose on for a hook-up but the problem occurs when I am trying to fill the tank. there is a drain spigot just below where the inlet is. I assume this is a drain. It runs out when I open it, so it's not clogged there. 

[Patrick Broderick]

Where is the vent?

[Darryl&Rita]

Proper way would be to re-route the vent line, to get rid of the low point. Otherwise, it'll just fill up again.

[mptjelgin]

Do you see an open hole near the screw off cap where you place the hose to fill your tank?? That is where the vent opening has been on all three of my trailers. 

[Alie&Jim's Carrilite]

5 minutes ago, mptjelgin said:

Do you see an open hole near the screw off cap where you place the hose to fill your tank?? That is where the vent opening has been on all three of my trailers. 

Correct, there should be a screen covering it. If the screen is gone, then an insect can clog the tube.

[Randyretired]

Our Teton had a similar problem that made trying to fill the water tank very difficult.   In our case the fill and vent were just inches above the tank.  The fill was in the front and the water tank was in the rear over the axles.  It helped to raise the front of the 5er before filling.  I have since moved the water fill up on the side and this solved the problem but the low spot in the vent buried deep in the wall somewhere  still gurgles.

[bigjim]

If you have the vent screen on it, the screen itself can get clogged with dirt and cause an issue.

[Kirk W]

11 hours ago, Patrick Broderick said:

It's the latter, I have a 1988 Tioga Mobile Home (Coach, I guess) which has a screw off cap that you just insert a hose and fill up from there. I also have a place where you screw the hose on for a hook-up but the problem occurs when I am trying to fill the tank. there is a drain spigot just below where the inlet is. I assume this is a drain. It runs out when I open it, so it's not clogged there. 

More than likely the fill that you have looks much like this one. The second picture is of the tank drain. 

                                                     

If this is what you have, notice the small hole at the lower-left (7:30 position) in this picture. That is the outlet of the vent line and they usually have a small plug connected to the tether for the cap which is intended to put into that hole to keep things out but some do not. If yours looks like this, I would first attempt to use a vacuum to pull out any water but if you can't co that, then compressed air might work. Even one of those pressurized cans for dust removal might do the job. If you remove the three screws that hold this one in place you should have enough slack in the two hoses to the fill & vent openings to be able to pull the part out and then check for slack in that vent line. It usually has a small, plastic hose that goes from it down to the top of your potable water tank. You should be able to see the ends of both hoses where they enter the water tank if you look there, just to know what it is that you will be dealing with. The water tank is probably under the bed or the dinette seat. 

[Patrick Broderick]

6 hours ago, Kirk Wood said:

More than likely the fill that you have looks much like this one. The second picture is of the tank drain. 

                                                     

If this is what you have, notice the small hole at the lower-left (7:30 position) in this picture. That is the outlet of the vent line and they usually have a small plug connected to the tether for the cap which is intended to put into that hole to keep things out but some do not. If yours looks like this, I would first attempt to use a vacuum to pull out any water but if you can't co that, then compressed air might work. Even one of those pressurized cans for dust removal might do the job. If you remove the three screws that hold this one in place you should have enough slack in the two hoses to the fill & vent openings to be able to pull the part out and then check for slack in that vent line. It usually has a small, plastic hose that goes from it down to the top of your potable water tank. You should be able to see the ends of both hoses where they enter the water tank if you look there, just to know what it is that you will be dealing with. The water tank is probably under the bed or the dinette seat. 

Boy, do I feel stupid. I never noticed the plug in the vent there! I just went out and looked and there it is, just like in this picture. Thanks so much. I still haven't tried filling it, I have to drag a hose over there but it definitely had a plug in it.  Thank you Kirk!

[KodiakJack]

I once had a kink in our fill hose.  Ran a electric fish tape through it and it cleared up (for a while).  Eventually had to revisit the fill hose when I was under the underbelly covering doing some work.  Found the kink and used electrical tie wraps to hold the hose in an unkinked position.  It's fine now but was a real pain filling the tank one drip at a time.

Later,

J