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Old 07-18-2020, 12:46 AM   #1
Junior Member
Brand: Thor Motor Coach
Model: ACE
State: Washington
Posts: 1
THOR #19679

I'm wondering if there is a shutoff valve to the san-t-flush system on a 2018 Thor ACE 30.3.
When i hook up a hose, water on to flush the Black tank with the drain valve open nothing drains out.

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Old 07-18-2020, 12:57 AM   #2
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16ACE27's Avatar
Brand: Thor Motor Coach
Model: ACE 27.1
State: Florida
Posts: 9,798
THOR #7035
Has it ever worked? Usually no valve installed BUT there have been cases where the hose from the outside connection to the sani-flush was not connected and cases where the check valve at the outside connection was installed backwards.
Ted & Melinda
2016 ACE 27.1
2016 Chevy Sonic Toad
2020 Chevy Colorado Z71 Trail Runner Alternate Toad
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Old 07-18-2020, 01:32 AM   #3
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EA37TS's Avatar
Brand: Entegra
Model: Accolade 37TS
State: South Carolina
Posts: 7,326
THOR #1469
There is a a one way check valve or vacuum breaker that when it malfunctions does not allow water through in either direction. Mine was under the bathroom sink. Changed it and the system was back to normal

Here is what was bad on my system a few years ago.
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Old 07-18-2020, 04:41 AM   #4
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Brand: Redwood
Model: 36FB
State: Arizona
Posts: 1,656
THOR #3610
Thor has also been known to mislabel the valves. You're sure you're opening the black tank? If so check the vacuum breaker, either installed backwards or has malfunctioned.
Danny & Linda
Sold '13 Thor Redwood 36 FB
Traded '13 GMC Denali DRW D/A
Currently RV & truckless
Replacement undetermined
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Old 07-18-2020, 01:11 PM   #5
Senior Member
Brand: DRV
Model: 44' Santa Fe
State: Montana
Posts: 384
THOR #2053
Several rigs ago I had a brand new rig that the backflo preventer was installed backwards. Won't work that way. Easy fix though. Good luck

If you are afraid to speak the truth out of fear of what others may think, it says a lot about who you are and what you will settle for.
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