MJM Yachts 34z Express - Manual (Page 29)

CHAPTER 9 GRAY WATER SYSTEM
- 29 - 34z
9.1 GENERAL
Gray water is liquid that can legally be pumped overboard, generally from sink drains, shower
drains, and bilges. Your boat also directs deck run-off to of all gray water through common drains
(port & starboard) in the transom.
9.2
GRAY WATER TANK
The gray water sump box aboard your boat is located in the bilge under the panel below the
bottom companionway step. This collects water from the shower drain, the refrigerator drain, and
the air-conditioning condensation (if fitted). The sump pump switch on the DC panel operates a
bilge pump with normal float switch to empty the tank when any of the above systems are in use.
Periodically, the cover of the tank can be removed and the contents cleaned.
9.3 BILGE
PUMPS
There are three bilge pumps fitted on your boat, and an emergency engine driven system.
The manual bilge pump under the starboard helm station is operated by opening the plastic
cover, inserting the handle, and pumping up and down. There is a noticeable difference when the
bilge has run dry. This pump is most often used as a back-up system to the two automatic
pumps. Its capacity is 15 gal/min.
The automatic pumps, located forward of the engine and under
the companionway steps, are wired directly to the house
battery bank. This means that even when the main battery
switches are OFF, the bilge pump can continue to function
properly. A three-way switch controls the pumps. When held in
the manual position, the pump will work regardless of whether
there is water in the bilge or not. In the OFF position, the pump
will not turn on. In the AUTO position operates if the water level
rises. If water is detected, the pump continues to run until the
water is gone. Generally, the pump should be left in the AUTO
position.
The 34z’s engine can also be used as an emergency pump.
This is accomplished by connecting a hose (garden type) to
the FLUSH port on top of the raw water intake seacock.
When
the handle is switched to the FLUSH setting, the engine will draw its cooling water from the hose.
It must find water in order to keep itself cool. It is not recommended to run the engine at high
RPM while using the emergency pump feature.
9.4 COMMON
DRAINS
To eliminate unnecessary thruhull penetrations in the topsides, a common drain system is utilized
on both port and starboard. [See Figure 14.7] Make sure, especially when air-conditioning is
running, that the outlets for these drains, located in the transom under the swim platform, are not
obstructed. Items that drain into the common drains include: hatch gutters, galley and head sinks,
deck drains, sump tank and air-conditioning discharge.
BILGE SWITCHES