Fresh water tank questions - may have shrunk

[Axel00]

Hello,

our fresh water tank has a capacity of 55 gal. now you can only fill 30 gal.

Some time ago I opened the drain valve at the bottom of the tank to empty the tank.
I suspect that not enough air could flow in and as a result the tank contracted a bit .

I'm looking for a solution to restore the original tank size.
I'm considering filling it with hot water, but I'm not sure if something worse can happen with it ???

Anyone have a suggestion
Thanks in advance.

 

[Mark_K5LXP]

I seriously doubt your tank has collapsed. How are you measuring the capacity?

Mark B.
Albuquerque, NM

 

[Axel00]

I have a water meter on the pipe, its works correctly

It is a fact that less water can be filled in than before.

 

[Mark_K5LXP]

My guess would be that either the overflow or the pickup piping has changed/moved somehow. Tanks that can old hundreds of pounds of water are not pliable and will not deform to 50% of their capacity.

Mark B.
Albuquerque, NM

 

[SpencerPJ]

I agree with Mark whole heartedly. A 50 gallon tank does not shrink, but make 100% certain it is vented.

If you are 100% certain it shrank, maybe a storage tank inflator would solve the issue.

 

[RVfixer]

On my trailer the vent line sags a little I guess and holds some water. As the tank fills air has to escape. Usually the pressure buildup while filling would blow the water out of the vent line. Once after the trailer sat over the summer...and I was only filling the trailer partially for on the road use when we did go out...that stagnate water in the vent line caused a plug and I could only get the tank a little over half full before it wouldn't take more water. When I pulled the hose end out of the gravity fill port I heard air escaping air out of the fill port so I new the vent line was plugged. After cleaning that line I could fill the tank completely.

 

[Axel00]

Those are some good approaches to narrowing down the problem.

Thank you everyone for the suggestions.

 

[Rene T]

Welcome to the forum.
Please get back to us if you figure things out. It may help others.

 

[bzerull]

is this an RV trailer? if so, the tank is long and rectangular in shape, without much depth. So, if the trailer is not level you may not be measuring all of the water.

 

[Kirk]

Is there any way that you can see the fresh water tank? In most RVs that tank is located under the bed, or somewhere inside of the RV where it is heated. What is your RV make & model as that might help us to figure out what the problem is. I agree with others that it could be a problem in venting the air from the tank. What type of tank fill do you have, one that you place a hose into on the outside, or is it one that has a valve to fill the tank from the city water connection? If you have the outside type and believe that the tank is full because water is blowing back at you, then it is quite possible a problem with the vent line. You may want to try running the water in very, very slowly to see if you can put more in as that would likely allow you to fill it more, even if you do have the vent problem suggested.

 

[Axel00]

Is there any way that you can see the fresh water tank? In most RVs that tank is located under the bed, or somewhere inside of the RV where it is heated. What is your RV make & model as that might help us to figure out what the problem is. I agree with others that it could be a problem in venting the air from the tank. What type of tank fill do you have, one that you place a hose into on the outside, or is it one that has a valve to fill the tank from the city water connection? If you have the outside type and believe that the tank is full because water is blowing back at you, then it is quite possible a problem with the vent line. You may want to try running the water in very, very slowly to see if you can put more in as that would likely allow you to fill it more, even if you do have the vent problem suggested.

 

[Axel00]

Thanks for your contribution.
Our 5th wheel has a double floor in which the tanks are located.
The tank is filled with a hose, no city connection.
I've already tried filling slowly and pausing in between, that didn't change anything.
I also blew through the ventilation and it is ok, because you notice that air blows out when filling.

 

[Axel00]

is this an RV trailer? if so, the tank is long and rectangular in shape, without much depth. So, if the trailer is not level you may not be measuring all of the water.

 

[Axel00]

Thanks for the hint...
Yes, it's a 5th wheel, is firmly in place and is well aligned.
As I said before... I'll have to do the work of removing the underbody

 

[Rob&Deryl]

A Robertson drive (square drive) and a variable speed drill motor will speed up removal.

 

[Kirk]

I'll have to do the work of removing the underbody

Please do keep us posted and share what you find once you gain access to the fresh water tank. It might be helpful to know that make & model your fifth wheel is as there may be someone here who has experience with that exact RV.