Anyone who has ever had a cottage or cabin that got it's water from a well knows
that, just opening the faucet doesn't mean anything worth using is going to come
out, if anything at all comes out. Wells need to be monitored for contamination, pumps
need to be serviced, and you have to add your own disinfectant to prevent bacteria. Even
though the water source, to fill the water tank, for most boaters is city water, the
last two items still can not be ignored.
Understanding how to
operate and maintain a marine water system becomes much easier if you understand what it
takes to install one and what the procedure is for getting it ready for use and for
testing it. This section covers installation of the pump and what to do to maintain the
system after the system is put into service.
SHURflo's Marine Duty Potable Water Pumps were developed to endure the harsh marine
environment. The patented Tri-a-fram" design delivers smooth, consistent flow at all
ranges of operation, while drawing low current. The balanced diaphragm design incorporates
precision ball bearings for long life. Each motor is equipped with an integral thermal
breaker and are all U/L Marine listed. All Marine duty pumps have sealed switches and are
finished with a baked-on polyurethane coating to inhibit corrosion. Marine duty potable
water pumps are enclosed to prevent incidental moisture from entering; however, they are
not intended for environments where splashed water is present. When installed correctly,
Marine Duty Potable Water Pumps provide years of quiet operation.
· The pump can be at the same level or below the water tank. It may be positioned
above the water tank if needed, as it is capable of a 6 ft. [1.8m] vertical
prime. Horizontal inlet tubing will allow priming to 30 ft. [9m].
· Consider a dry location that allows easy access if maintenance is required. The
pump should not be located in an area of less than one cubic foot unless
adequate ventilation is provided. Excessive heat may trigger the integral thermal
breaker and interrupt operation. When the temperature drops the breaker will
automatically reset and start operation.
· The pump may be mounted in any position. If mounting the pump vertically, the
pump head should be in the down position so that water will not enter the
· Use #8 stainless steel hardware to fasten the pump. Choose a solid surface (thick
plywood) that will not amplify pump operation. The mounting feet are intended
to isolate the pump from the mounting surface; over tightening, flattening, or use
of oversized screws will reduce the ability to isolate vibration/noise.
· The pump should be on a dedicated (individual) circuit protected by the specified
"slow blow" fuse indicated on the motor label.
· A U/L approved marine duty (ignition protected) switch rated at or above 15 amps is
recommended, and must interrupt current flow on the positive (+ red) lead.
· The pump must be grounded to a "known ground" (battery). The ground wire must
be the same size (gauge/mm2) as the positive wire.
· Wire size (gauge/mm2) is based on the distance from the power source to the
pump. The minimum recommended size wire is #14 gauge [2.5mm2]. Lengths of 20-50
ft. [6-15M] use #12 gauge [4mm2].
· The total current draw on the circuit must not exceed 15 amps. If the pump is used in
conjunction with other components, overload current protection (fuse or circuit breaker)
and wire size must he for the total amp requirement of all devices on the circuit.
· SHURflo recommends at least 1 ft. [.3M] of 1/2"[13 mm] ID. flexible high pressure
tubing to both ports. Ideally the pump's ports/strainer should not be connected to plastic
or rigid pipe. The pump's normal oscillation may transmit through rigid plumbing causing
noise, and possibly loosen or crack components.
Installation of a 50 mesh strainer is recommended to prevent foreign debris from entering
· ShurFlo swivel barb fittings provide easy removal if maintenance or access is required.
The fittings are designed with a "taper-seal", creating a water tight connection
when hand-tightened. Always secure barb tubing connections with properly sized stainless
steel clamps to prevent leaks. Never use Teflon tape or sealing compounds on threads.
Sealer may enter the pump causing a failure. Failure due to foreign debris is not covered
· Rapid cycling may be caused by excessive back pressure created by one or more of the
following within a plumbing system:
- Water filters and purifies not on separate feed lines.
Flow restrictors in faucets and shower heads.
- Small ID. lines. Pipe/tubing should be at least 1/2"[13 mm] I.D. for main lines.
- Restrictive fittings and connections (elbows, "T's", feeder lines to faucets,
ADJUSTMENT OF SWITCH (Shut Off)
Restrictions in a plumbing system may cause the pump to rapid cycle (ON/OFF within 2 sec.)
during low flow demands. Cycling should be minimized to prevent pulsating flow, and to
achieve maximum pump life.
To determine if adjustment is necessary, turn a faucet ON to lower than average flow of
water. The pump should cycle, but its "OFF time" must be 2 sec. or longer. If
the cycling is correct, leave well enough alone. If the pump is cycling rapidly increase
the setting by turning the screw clockwise (1% turn MAX.) until the pump operates for 1
sec. with at least 2 sec. "OFF time". If cycling cannot be minimized consider
removing plumbing restrictions or simply install a SHURflo Accumulator.
Potable water systems require periodic maintenance to deliver a constant flow of fresh
water. Depending on use and the environment the system is subject to, sanitizing is
recommended prior to filling and before using the water system after a period of storage.
Systems with new components, or ones that have been subjected to contamination, should
also be disinfected at; follows:
1. Use one of the following methods to determine the amount of common household bleach
needed to sanitize the tank.
A) Multiply "gallons of rank capacity" by 0.13; the result is the ounces of
bleach needed to sanitize the rank.
B) Multiply "Liters of tank capacity" by 1.0; the result is the milliliters of
bleach needed to sanitize the tank.
2. Mix into solution the proper amount of bleach within a container of water.
3. Pour the solution (water/bleach) into the tank and fill the tank with potable water.
4. Open all faucets (HOT&COLD) allowing the water to run until the distinct odor of
chlorine is detected.
5. The standard solution must have four (4) hours of contact time to disinfect completely.
Doubling the solution concentration allows for contact time of one (1) hour.
6. When the contact time is completed, drain the tank. Refill with potable water and purge
the plumbing of all sanitizing solution.
NOTE: The sanitizing procedure outlined above is
with the approved procedures U.S. Public
If water is allowed to freeze in the system, serious damage to the plumbing and the pump
may occur. Failures of this type will void the warranty. The best guarantee against damage
is to completely drain the water system. However, non-toxic antifreeze for potable water,
available at local marine centers, may be used.
CAUTION: Do not use Automotive Antifreeze to
Such solutions are highly toxic.
cause serious injury or death.
To properly drain the system perform the following:
1. Drain the water tank. If the tank doesn't have a drain valve, open all faucets
allowing the pump to operate (l5 min. ON / 15 min. OFF) until the tank is empty.
2. Open all the faucets (including the lowest valve or drain in the plumbing) and allow
the pump to purge the water from the plumbing, then turn the pump OFF.
3. Using a pan to catch the remaining water, remove the plumbing at the pump's
inlet/outlet porn. Turn the pump ON, allowing it to operate until the water is expelled.
Turn OFF power to the pump once the plumbing is emptied. Do not reconnect pump plumbing.
Make a note at tank filler as a reminder: "Plumbing is Disconnected".
4. All faucets must be left open to guard against any damage.
For a downloadable system diagram click here.
Pump cycles too much? Add an