The new holding tank and blackwater plumbing system are
installed and tested. The system has
gone through quite an evolution. I
posted my initial concept here on the website and on the Morgan 38 Discussion Board.
 |
| The original schematic for Pilgrim's blackwater plumbing |
Thanks to comments, questions, and feedback from you all, I
made a few modifications prior to beginning the project. Once completed the initial installation
looked like this…
 |
| The actual layout of the initial installation. |
Since Pilgrim is on the hard testing the system required routing
the head raw water feed line to a 5G bucket of water. This plumbing detour allowed me to flush the
toilet both overboard and into the holding tank. The system worked flawlessly during this
test. For the next test I filled the holding tank with fresh water via the pump
out fitting on deck. While watching the
tank fill, I realized a shortcoming of the design – the Henderson MKV Pump was mounted lower
than the holding tank. With the valve at
the tank exit set to offshore discharge the Henderson Pump the pump would flood. I questioned whether or not the flapper and
joker valves in the pump would operate properly with constant positive pressure
from the holding tank. The Henderson Pump
performed the task of empting the tank without issue, but... my design would leave the valves of the pump
submerged in black water anytime the tank exit valve were open to the
pump. I feel certain that prolonged
immersion in black water would cause the valves to fail unless they were
regularly cleaned. Monthly or weekly
cleaning of the head pump internal valves is not a task I want on my regular
maintenance list!
The next (dare I say final?) evolution…
 |
| The current, and I believe final, installation of Pilgrim's black water system |
Despite my resistance to adding another electric pump to the
vessel, mounting the Shurflo
3200 Macerator below the level of the black water tank is within its design
specs. I also inverted the “Y” valve in
the offshore discharge line. Flipping
the valve allows all the waste in the line to empty past the valve. In the previous design a small amount of
black water remained in the valve after use.
Using the same methods as above… 5G bucket of water plumbed
to the toilet feed line and filling the holding tank via the deck pumpout
fitting, I have successfully tested all the functions of this system.
 |
| Flushing head offshore the waste follows the path highlighted in red. |
 |
| Flushing to holding tank the waste follows the path highlighted in red. |
 |
| Discharging the holding tank via the deck pump out fitting the waste follows the path highlighted in red. |
 |
| Discharging the holding tank offshore the waste follows the path highlighted in red. |
Additional images and notes from the installation can be found in our on line Holding Tank Installation Photo Album - 2014
Does the final installation of your head and macerator pump include two (2) vented loops? It looks like you have one (in the diagram) just after the outlet of the pump, but the depiction in the drawing is a little different than the other vented loop in the drawing.
ReplyDeleteThe final assembly has two vented loops. One between the head pump and the thru hull seacock (when flushing head directly overboard) and one between the macerator pump and the thru hull seacock (when emptying the holding tank overboard).
Delete