Thor Compass 23TW FW Tank Venting

[Ezrider525]

I recently purchased a Thor Compass 23TW and absolutely love the unit; my wife and I have been really enjoying it. While there have been a few minor issues, the dealer has been extremely helpful in getting them resolved.

One issue I’m hoping to troubleshoot myself (though I may ultimately need to bring it back to the dealer) involves the freshwater tank:

• When I fill the fresh water tank, water starts coming out of the overflow drain underneath the RV when I put about 15 gallons in from empty
• At that point, the BM Pro system indicates that the tank is full.
• However, once the water finishes draining from the overflow, the BM Pro reading drops to about 1/3 full.
• I purchased an inline gauge for my hose, and it seems the tank only accepts about 15 gallons before the overflow begins—nowhere near the tank’s stated capacity.
• I’m not sure how much water is lost through the drain before it finally stops, but something definitely seems off.

Please reference the attached. The water is coming out the smaller white tubing on the left.

I spoke with someone in the service department where I purchased my unit new who suggested the issue could be related to the sensors, or possibly that the drain tubing isn’t routed properly.

Has anyone experienced something similar? If so, how did you resolve it? Thank you.

 

[16ACE27]

There was a recent post on the same "overflow" issue. Seems Thor put in two overflows/vents. They ended up putting a valve on the end of that white pipe.

Fix that issue and then fully drain, then fill the FW tank and see what you get.

 

[Ezrider525]

Thank you so much for your reply. Yes, I actually saw the same message pop up after I submitted mine. So I should just install a valve on the second drain pipe and just leave it in the off position and I should be good to go? Per your advisement, from there drain the tank all the way and then refill.

 

[Gus52]

There was a recent post on the same "overflow" issue.

We are one of the same poster(s) and did the valve add mod. We are out and are building experience with the fix and issues. It appears the vent at the fill is too small. If I leave the valve closed and use the water system the water heater is not 100% water. By messing with a second valve I can carry a full tank of water, but need to remember to open the valve when parked. It will drop a pint of water at first due to the driving stirring action but becomes a good vent after that. I think the vent at the fill has too small of holes to let enough air through.

I did have a water pump problem that let the city water reach the fresh water storage tank. The Thor setup would help with that, however the vent at the fill would also do that job. So I really can't see a lot of value for the second vent. I may increase the fill vent "plastic screen" size to see if that will be good enough, or just drill it out to the ID of the fitting like so many other RVs have.