True measured holding tank capacity's, This is LONG, read complete post.

[Big Bear]

Just replaced my sensors with the "Horst" tank sensors. My black tank has been "full" since shortly after I bought this M.H. 2004. The gray was almost as bad rarely showing below 2/3. I have tried chemicals, Dawn, water softener powder, Borax and many more including ice in the tank but nothing has worked. Winnebago has told me that I have a 52 G black & 48 G gray. My owners manual does not show capacity for the 40AD, only for models 34TD & 36GD. Size of 36GD is 52 & 48, same as Winn tells me is correct for my model.
I checked the wiring diagram on the internet, confirmed it matched what I have and started installation of new sensors after confirming with a jumper that each wire on both tanks did what they were supposed to do. I called Winn again and asked if there was a specific location for each sensor as they appeared to be installed somewhat randomly, was told that because of tank configurations/shapes they might look "off" but were correct as the holes were located with a "dimple" showing where they were to go. New sensors are in, and tanks both read empty, 1st time in years. As I now have access to the tanks & sensors I thought it was a good time to test everything before closing it up. Blk tank, 52 ga, working in 1/3rds it should be 17.3 + 17.3 + 17.3. I poured 1 ga water in toilet & marked the bowl. After 23 ga, the 1/3 blinked, 1 more ga showed a steady1/3 light 24 ga total. Continued adding water after another 14 ga and the 2/3rd blinked, another 13 ga showed a steady 2/3 light, thats 27 ga for the 2nd 3rd of the tank or 51 ga for 2/3 tank from empty. Try for the full light so 11 ga brought it up to 8" below the top of ball seal, 1 more ga to 6" below ball, ! more ga to 4 below ball and it "burps" back to the bowl after the last 2 ga. sixty two ga (51 + 11) ga seems to be as much as you can use in this tank AND I never got to the full mark.

Gray tank was better, 48 ga cap= 16 1/3 ga for each section.
Marked the wash basin at 1 ga and started again. after 18 ga a solid 1/3 light, another 12 ga & the 2/3 light blinked but was not solid until I reached a total of 22 ga.
there is now 40 measured ga in this 48 ga tank and only 2/3 full. Added another 10 ga watching for the full light and for water in the shower no light but I hear water burping in the shower, another 10 ga and I think it is full, did not come up in the shower but when I added water in the shower did not want to drain. So usable gray tank may be around 50 ga, and still no full light.
These are all measured and should be very close, the MH was on jacks and level during this.
After this I question the location of the tank sensors as well as the capacity, I will be calling Winn Monday but am interested in any comments you may have. Oh yes, they now read empty when they are empty.

Vern Phoenix
2004 Vectra 40 AD Cummins 350 W/Banks power package
2004 PT Cruiser, GT, Turbo, w/5 speed
Blue Ox Avanta 3 & Blue Ox tow plate W/Brake Buddy
Good Sam, long time Thousand Trails, & . FMCA

[sdennislee]

On the upside, sounds like the inaccurate sensor placement gives you a built in safety margin. i wonder if that was intentional. Winnebago may have figured some people will wait to dump until the full light is solid.

[Midniteoyl]

Ya.. my manual says 40gal, the tanks say 47gal, but they'll hold 50-51... There appears to be a little for those that go over, plus some for air...

[sam-tip]

Wonder how much water the drain pipes hold.

[Midniteoyl]

Mine? 1/2 gal.. the drain is right there..

[Five2o]

[QUOTE=Big Bear;954086]Just replaced my sensors with the "Horst" tank sensors. My black tank has been "full" since shortly after I bought this M.H. 2004. The gray was almost as bad rarely showing below 2/3. I have tried chemicals, Dawn, water softener powder, Borax and many more including ice in the tank but nothing has worked. /QUOTE]


A little off topic but I started adding 1/2 cup Sunlight dish soap to each black & grey water tank right after dumping....have never had an indicator light stick since...(after a year of constantly sticking lights)