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Flushing our Black Tank to clean it out before winterizing


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My hubby and I are trying to flush and clean out the black tank before winterizing.  We found the open valve under the table, turned it the way the pic in Oliver book shows, but water is NOT coming in and filling the tank.  What are we doing wrong??  And is there any video someone has posted of an Oliver?  We can't find anything on the forum.  No luck yet, anyway.  I have noticed when looking at old posts, the pics or video links are missing.  TIA!!  Rolayne and Rob Volpe, Hull #166

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Just curious...did you hook the hose to the special black tank flush hookup? The flush system is not hooked to the rest of the plumbing. The hook up valve is on the driver side, outside, near the front. I also pump some antifreeze in that hose, though it doesn't take that much...

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If you don't figure it out, an alternative is to step on the toilet flush valve and run a garden hose into the toilet.  It feeds directly into the black tank.

TV:  2019 F-150 SuperCrew Lariat, 3.5L EcoBoost, Max Tow, FX-4, Rear Locker      OLLIE:  2018 OE2 Hull 342, Twin Bed.    OLLIE DYI’s:  BB LiFePO4's, Victron 712 Smart, 350 Amp Master Switch, Houghton 3400, Victron Orion DC - DC, 3000-Watt Renogy Inverter, P.D. 60-amp Converter, Frig Dual Exhaust Fans, Kitchen Drawer Straps.    TV DYI’s:  2 5/16" Anderson System, Timken Bearings, Nitto recon’s, Firestone Rear Air Bags, Bilstein 5100’s, Mud Flaps & Weather Tech all.







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Did you ever figure this out? If you are indeed hooking up city water to the outside black tank connection and the manual valve is open under the front dinette area, then there is a blockage, or perhaps the check valve was installed backwards. The latter is unlikely, you would have seen signs of a sewage leak at the outside connection.


It’s a pretty simple system - unless there is user error, not much can go wrong.... Regardless, I think flushing the tank often would be smart, to prevent any issues with the spray nozzles getting plugged up, or the, uhmmm “deposits” hardening on the inside of the tank. You can always try the ice cube trick. Empty a big bag of ice down the toilet with a few gallons of fresh water and immediately tow the Ollie around for an hour or two. The ice will break up any hard stuff.


John Davies


Spokane WA

SOLD 07/23 "Mouse":  2017 Legacy Elite II Two Beds, Hull Number 218, See my HOW TO threads: https://olivertraveltrailers.com/topic/john-e-davies-how-to-threads-and-tech-articles-links/

Tow Vehicle: 2013 Land Cruiser 200, 32” LT tires, airbags, Safari snorkel, Maggiolina Grand Tour 360 Carbon RTT.

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