31UL Black/Gray Blocked

[BruceT]

Recently found my black and gray blocked on my 2018 Precept 31UL. We NEVER leave the valves open and both tanks confirmed full. We’re on a 2500 mile trip. No kids & 30 years RV experience.
HOW THE PROBLEM WAS SOLVED:
1. My model has built-in mascerator.
2. Opened GRAY and nothing dumped.
3. Opened BLACK and nothing dumped.
4. Blockage is BELOW the “Y” junction.
5. Mascerator box is suspect as it is below “Y” junction. Mascerator is not operational. Not interested in troubleshooting that right now.
6. Attached fresh water hose to mascerator hose.
7. CLOSED black and gray valves.
8. OPENED outlet valve.
9. Turned on water and clean water came out. This indicated exit from mascerator was clear.
10. CLOSED outlet valve.
11. OPENED black and gray valves.
12. Turned on fresh water backfeeding through mascerator. This forced the water through the mascerator and back into the tanks.
Heard gurgling in the tanks.
13. OPENED outlet valve. BLACK and GRAY already open. Tanks emptied! PROBLEM SOLVED.
14. This method will work on BLACK or GRAY blockages.
NO TOOLS REQUIRED!