? My freshwater tank is draining/ It was never filled?

khd995

Active Member
I have an 07' 3400 RL. As I understand the layout of the tanks, I have a drain on the freshwater tank (at least I thought it was the drain for only the freshwater tank) and a couple of valves on the docking station for emptying the lines.

I am getting ready for winterizing my unit and opened the freshwater tank drain (which I never filled) and it somehow drained what appeared to be several gallons of water.

Next I dumped my greywater and black tanks. I left both of my grey water tanks and the drain on my freshwater tank open for no particular reason. This morning after my shower, I walked outside and heard running water. I looked under my trailer and there is a stream of water coming out of my freshwater drain.

Is there a connection between these tanks that I am unaware of or is the drain somehow common to the three tanks.

This has me baffled.
 

mrcomer

Past Ohio Chapter Leaders (Founding)
Sound like it may be a bad check valve probably somewhere close to your pump. It may be installed backwards causing the city water to get into your fresh water tank.

Mark
 

khd995

Active Member
This maybe a stupid question but, where is the check valve, what does it look like, is it part of the water pump.

Basically how do I identify it so that I can replace it.
 

jpmorgan37

Well-known member
khd995;

I'm not sure if your valving is the same as mine, but if I have my valves set to use my water pump to supply water to the coach, and have city water connected, it will slowly fill my fresh water tank through the water manifold. Just a thought.

John
 

khd995

Active Member
Maybe that is what I have going on. I had never used my freshwater tank. But recently I did fill it because we were without power and wanted to have some water in reserve if the well went out.

When I tried to test it the pump wouldn't pump anywater. I got in the basement and opened a valve that led to the freshwater tank and it worked. Well the power came back and I drained the tank.

Then I hooked back to the city water last night and walked away, then this morning I found the water draining out of the freshwater tank. I just shut the valve and that stopped the water into the freshwater tank.

Is this normal. That if you want to switch from city water to freshwater you would have to get into the basement to open the valve. Or is there something wrong with the pump. Seems like something besides a manual valve in the basement should stop water from backfilling into my freshwater tank.
 

Ray LeTourneau

Senior Member - Past Moderator
The internal valving on the Shurflo pumps has a built in check valve. Ours failed the first time we used the pump. At first our pump wouldn't shut off, we cleaned out a little plastic debris in the pump head and it worked for a while but not the way it was supposed to. Then all of a sudden we noticed our fresh water tank was back filling through the pump if we were hooked up to city water. Check valves failed. There is a ball valve in the line between the pump and the tank that can be closed as a temporary measure. Your dealer should be able to get a new pump unless your're out of warranty. You could call Shur-flo and plead your case and they might send you a new pump. They did that for me. It's a 10 minute job to change out the pump.
 

khd995

Active Member
Ray, thanks for the info about shurflo. I called this afternoon and spoke with them and when I told them the model number (3900-0206) they said to UPS it to them and they would send me a new ASAP. The guy I spoke to said the the model 3900-0206 had known defect and they had replaced as many of them as they could locate from the original ones manufactured from 05'-06'.
 
Top