Forum Discussion
Old-Biscuit
Jul 17, 2017Explorer III
DO all three tanks drain thru a 'common header' to one outlet?
If YES........
THen simple mod
Add an extra valve in horizontal run of drain header.
With it closed......
You can open grey tank and black tank drain valves and let them equalize
All three valves open.......114 gal WASTE capacity (14 gals more then fresh water tank capacity or 4 gals more then fresh water capacity ---fresh water tank and water heater)
I have done this mod on several of my trailers ....waste is waste
If not wanting to do the permanent valve install (3" drain valve and 2 flanges) there is a 'twist on' drain valve that installs right on end of drain line. Remove end cap, twist valve on.
I prefer the permanent....it isn't hanging on end of drain pipe adding extra weight, have to remove/stow for travel otherwise it is bouncing and could crack drain line or 'teets' that hold it in place.
About $25 for twist on

About $15 for glue in place

If YES........
THen simple mod
Add an extra valve in horizontal run of drain header.
With it closed......
You can open grey tank and black tank drain valves and let them equalize
All three valves open.......114 gal WASTE capacity (14 gals more then fresh water tank capacity or 4 gals more then fresh water capacity ---fresh water tank and water heater)
I have done this mod on several of my trailers ....waste is waste
If not wanting to do the permanent valve install (3" drain valve and 2 flanges) there is a 'twist on' drain valve that installs right on end of drain line. Remove end cap, twist valve on.
I prefer the permanent....it isn't hanging on end of drain pipe adding extra weight, have to remove/stow for travel otherwise it is bouncing and could crack drain line or 'teets' that hold it in place.
About $25 for twist on

About $15 for glue in place

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RV projects you can tackle on your own with a few friendly pointers.4,353 PostsLatest Activity: Feb 14, 2025