Fill Water From City - Water Tank Ballooned. Need water pressure relief valve?

[heimlich]

I filled my water tank half way. I noticed that when I did this the tank ballooned. It was becoming pressurized. Is there a valve I can put on the hose that will release this pressure? I also have some outlets on the tank I could put this on. I'm guessing I need some type of water pressure relief valve.

Has anyone else had this issue? How did you solve it?

 

[ewo1]

Is your water tank vented?
Should not pressurize if vented.
Maybe the tank walls are too thin...weak?

 

[heimlich]

I didn't vent the tank. I closed off all the holes. To release the air I screwed out one of the fittings I had in there. When I let the air out everything was fine.

Is there a special type of vent that will let air out but not air into the tank?

 

[jimmythomas]

I didn't vent the tank. I closed off all the holes. To release the air I screwed out one of the fittings I had in there. When I let the air out everything was fine.

Is there a special type of vent that will let air out but not air into the tank?

You need to vent it both ways, other wise the tank will collapse when you try to get water out.

 

[Drew Bru]

We vented our tank and still have the same problem if we fill too fast. We end up sorta "burping" the tank by shutting off the water and letting the air release. We need a bigger vent hose. We don't have that problem with the gypsy wagon we built. But yeah, you absolutely need a vent hose from the top of the tank to the outside (our fill fixture has an opening for the vent to clamp to) otherwise the displaced air has nowhere to escape and you run the risk of bursting your tank.

 

[heimlich]

OK. So maybe I can drill a millimeter hole somewhere. Any better ideas?

 

[Tejon7]

My vent hose is 1/2" and I feel like it's just barely big enough to keep the tank sides from sucking inwards and 'glugging' when I drain the tank after flushing it out. 1/2" hasn't given me any problems during normal use though.

Can you run a breather hose from one of your plugged fittings to wherever your water inlet is on the exterior of the bus? I like it that way because it's easy to tell when the tank is full. When water gushes out onto your shoes, you're good to go!

 

[Drew Bru]

My vent hose is 1/2" and I feel like it's just barely big enough to keep the tank sides from sucking inwards and 'glugging' when I drain the tank after flushing it out. 1/2" hasn't given me any problems during normal use though.

Can you run a breather hose from one of your plugged fittings to wherever your water inlet is on the exterior of the bus? I like it that way because it's easy to tell when the tank is full. When water gushes out onto your shoes, you're good to go!

Yeah, that's exactly what we did on our build. A 1mm hole won't cut it, OP needs to run a hose from the fitting that he plugged to the exterior so when the tank gets overfilled it squirts him in the chest (as is the time honored tradition).

 

[fo4imtippin]

My tank had 4 holes, 2 on top and one on bottom. I teed the bottom together and ran to my water pump (as well as a valve to drain). I Teed the top 2 together and ran a hose out the bottom of the bus. When the tank is full, it wll pour water out the bottom and not shoot back at me. I did have to add 12v normally open ball valve that closes when the key is on as i would loose 30 gallons of water during the drive.

 

[heimlich]

My tank is right inside the rear door of the bus. To fill it I attach the hose to a device that screws into the top of the tank. I open the rear door to do that. I never added a drain valve so I might need to pull the tank to do that.

I have a little half inch fitting on the top of my tank on one end. I plugged it with a fitting. I might be able to do that.

Good point about the sloshing of the water when driving. I wouldn't want the water coming out of the over pressure area.

 

[nikitis]

We vented our tank and still have the same problem if we fill too fast. We end up sorta "burping" the tank by shutting off the water and letting the air release. We need a bigger vent hose. We don't have that problem with the gypsy wagon we built. But yeah, you absolutely need a vent hose from the top of the tank to the outside (our fill fixture has an opening for the vent to clamp to) otherwise the displaced air has nowhere to escape and you run the risk of bursting your tank.

Slow to fill means either low pressure in your hose, or your vent is too small. There's no reason you couldn't have a really large vertical vent.

Most will want to vent up into the cab too so there's no chance of road dust getting into your tank in reverse through the vent.

 

[Kentucky Dreaming]

You absolutely need a vent hose from top of tank to outside ABOVE the level of the top of the tank. Air needs to get out as you fill and in as you use water. My POS truck camper has 1 1/4' diameter vent hose. it works fine. I can hear the air coming out as I fill it. When the air stops, I know water is at the top of the tank and in the vent hose.
I never lose water while driving because the vent exits the camper above the top of the tank.