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jj141979 · 03-28-2012, 06:32 PM

We are going on our first camping trip Saturday!!! The season dont start till April 13th. But we are allowed to camp all year. The water wont be turned on till then. Now I wanna fill my fresh water tank up before we leave the house so we have water for the 2 days were up there. The tank has a overflow line on it. Question is should I plug the overflow line so I dont loose any water on the way up to camp with all the water sloshing around or should I not worry about loosing that much water?????

BFlinn181 · 03-28-2012, 07:12 PM

I wouldn't worry about losing a little water from the tank in transit. If you block the overflow, the cold water, upon warming up, could expand a bit and 'bulge' the tank. This could cause structural damage. Also, don't forget, water weighs just over 8 lbs. per gallon. Your fresh water tank holds 46 gal., that's over 370 lbs. Don't overload the trailer!

jesilvas · 09-23-2012, 05:48 PM

I'll bump this for anyone thinking of doing this: DON'T!
The "overflow" line is a vent hose. You putting water in a tank filled with air displaces the air. If you don't let the air vent out and be replaced by water, you could burst the tank.
Also, you are not gonna lose much water plugging that line anyway. Just don't risk it.
I would also make sure that the support structure holding the fresh tank is good. A couple angle brackets and wimpy "straps" under it may not necessarily work.

Tony Lee · 09-23-2012, 08:28 PM

Some RV water tanks and associated systems are pathetically-designed and a common problem is that when travelling it is possible to lose a fair bit of the water through the vent line - often because of surging that gets a syphon effect going and water flows until the tank collapses enough to counteract the syphon suction.

Couple of fixes - one is to run the vent so the outlet is a little higher than the tank - perhaps into a wheel well - and the other is to put a tap on the vent line. If the tank has a gravity fill point then there is usually a secondary vent there that prevents overpressure or collapse problems, but you still need to be careful not to forget to open the tap when filling fast from a high pressure town supply because the resultant bulging can cause damage.

BTW - temperature expansion of water isn't going to cause any problems. Water expands, but so does the tank material

BigBill3111 · 09-28-2012, 12:27 AM

Quote:

Originally Posted by BFlinn181

I wouldn't worry about losing a little water from the tank in transit. If you block the overflow, the cold water, upon warming up, could expand a bit and 'bulge' the tank. This could cause structural damage. Also, don't forget, water weighs just over 8 lbs. per gallon. Your fresh water tank holds 46 gal., that's over 370 lbs. Don't overload the trailer!

I had probably a half tank of water left in my 40 gallon tank after the last camping trip from several months ago. My wife and I were out in the trailer a few weeks ago and I heard her running water in the kitchen sink BUT I did not hear the pump running. I asked her if she had turned the pump on and she laughed and said no, she forgot to. It amazed me that water was coming out at NORMAL flow and continued to for at least a minute, until it finally settled to a trickle. It has been crazy hot here in Las Vegas, and the vent apparently did not let the build up of pressure out. I took my air hose and tried to blow through the vent, but I don't think I accomplished anything. Any suggestions from anyone ?

Tony Lee · 09-28-2012, 12:39 AM

Go easy with the air hose.

Mud daubers blocked the vent line
Vent line kinked

BigBill3111 · 09-28-2012, 01:05 AM

Quote:

Originally Posted by Tony Lee

Go easy with the air hose.

Mud daubers blocked the vent line
Vent line kinked

It has a little screen at the opening so I don't know if insects could be the problem or not. I will have to crawl under the trailer and see if I can locate the problem. It has the barrier on the bottom. Thanks for your reply.