Grey tank draining slow

[bytecrafter]

We have a 2021 Jayco Jay Flight 34 RSBS. The grey tank in the middle is draining slow and I can hear the tank gulping for air as it drains. Any ideas or suggestions?

Thank you.

[TWP723]

Did you check the vent on the roof?

All tanks need to be vented to drain.

[TCNashville]

Gray tank plumbing have what's called an Air admittance valve[s]. I have 2 in my camper. One located up under the bathroom sink and the other located up under the kitchen sink. These valves allow air into the system. They look like a cap on the plumbing. If one of these goes bad, it won't allow the tank to drain properly and it will burp as you described. Throwing this out there as a possibly.

[Randel J]

As a quick temporary fix, make sure your sink drains are not plugged up. If the roof vent and check valves are plugged, an open drain should help.

[RogerR]

The slow drainage may be due to a blockage from construction trash. I don't know the routing of you pipe but if you can, use a garden hose as a cleanout may help. If you suddenly get a lot of flow that slows again when the hose is removed there could be a chunk of something to big to go down the pipe. Then maybe a warranty job to take it out and remove the blocage.