Community Forums

THenne1713 · 08-19-2022, 12:58 AM

<< Is the gray tank that shallow?>>

YES, they can be, many gray/ black tanks have a tapered bottom. I suspect the inside of my black is only 2" to-4" deep at the higher, shallow end, (where toilet connects) which explains why I ONLY have about 1-inch clearance around down-pipe from toilet, (end of pipe to bottom of tank) which also leads to frequent clog potential, and occasional real clogs. From memory, 6"-8" deep on drain end, tank about 18"-wide, ~6-feet long, (25-33-gal??). Suspicion is gray tank is VERY similar.

Springhook · 02-08-2024, 10:47 AM

So, after several trips and much scrutinizing, I've at least discovered WHEN this happens. It happens when the MH is level or tilted away from the gray tank sewer drain and valves. If I park in an uneven site with the MH leaning towards the sewer and drain valve, all is well. I suspect the tank is askew somewhat.

twinboat · 02-08-2024, 01:24 PM

Vent pipe may be set way to low in the tank. 6 gallons covers the end and now water must push up the vent pipe. Won't go higher the the sink your pouring water in.

A floating tank cutout wouldn't float over the opening ever time.

LETMGROW · 02-09-2024, 06:47 AM

Quote:

Originally Posted by twinboat

Vent pipe may be set way to low in the tank. 6 gallons covers the end and now water must push up the vent pipe. Won't go higher the the sink your pouring water in.

A floating tank cutout wouldn't float over the opening ever time.

This makes sense as anything floating around in the tank would have moved out of the way long before now.
I would collect any invoices you have from a dealer or dealers who may have looked into this for you and then contact the builder of your RV about the issue. Hopefully the company will honor the warranty as this has been a problem from the outset.

THenne1713 · 02-09-2024, 02:44 PM

More than one owner of more than one brand of coach has found the plug from drilling the hole was left in tank and caused drain issues. QA on assembly is not common in RVs.

SUGGEST: 1) Tank mounts loose/ failing/ tank slope need to be inspected to eliminate as possible cause.

Many black/gray are style with sloped bottom, and laid on large side down= not tall, = under floor. Many in catalog are rectangular, and best gage orientation of tank would require toilet 2-3-feet above RV floor. E.g. Laid down flat, these same tanks 1-inch change= 10-gallons+/-, so RV leveling is critical, and too much wrong slope can stop tank from emptying by x-gallons, as you observed.