MJM Yachts 36z Express - Manual (Page 45)

CHAPTER 10
10.1 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.
10.2 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.
10.3 BILGE PUMPS
There are three bilge pumps fitted on your boat, and
an emergency engine driven system.
The manual bilge pump under the 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 three automatic pumps. Its capacity is 15
gal/min.
The automatic pumps, located aft in the engine
compartment, in the cockpit locker and under the
companionway steps, are wired directly to the 24
hours 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, you can check pump operation as 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, the pump 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.
10.4 HIGH WATER ALARM
A high water alarm is fitted to the boat with the sensor located aft in the engine compartment
and the control panel on the bulkhead to starboard of the wheel.
10.5 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.
GRAY WATER SYSTEM
BILGE PUMP SWITCHES
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