When choosing the proper model Seawater Pump , primary consideration should be given to the BTU capacity of the condensing
unit(s) and the available power supply.All centrifugal pumps must be located as far below the water line, andas close to the center line as possible.This prevents exposure above the
water line when the vessel is on the plane or operating in heavy seas.
Install the pump as close as possible to the seawater strainer and thru-
hull fitting.Mount the pump securely in a horizontal position with the dis-
charge higher than the intake.Rotate pump head towards the direction of
water flow as long as the outlet remains above the inlet.All of the above
helps to prevent any air locks that can cause the pump to cease proper
operation and cause damage to the components.The entire seawater system should be plumbed on a continuous uphillincline from the thru-hull intake to the condenser coil inlet.Locate the overboard discharge above the water line and connect it to the condenser coil outlet.The unit condenser coil should be the high
point of the application, if possible, thus eliminating a place to trap air and
maintaining a self-purging system.The thru-hull fitting should have a clam shell type scoop, facing forward,to help maintain a constant water flow to the pump.The thru-hull fitting
and seawater strainer must be sized considering both the required flow
rate of the system and the pump inlet.Restriction of flow capacity to the
pump intake can result in damage to the pump components.The thru-hull fitting should be dedicated to the system and not sharedwith other components or systems.The seawater strainer should be of
adequate size and should be located in an accessible area for maintenance (cleaning).A shut-off valve sea cock must be installed at the thru-hull fitting to pro-vide a means to service any component below the water line.All seawater components should be assembled using properly sizedflexible reinforced hose to provide vibration isolation.All fittings must be
full-flow fittings.Securely fasten each hose run, making sure no kinks or loops exist.Avoid or minimize 90°elbow fittings to ensure maximum
water flow.All hose connections must be double-clamped, reversing the
clamps, above the water line as well as below it.When installing multiple units, a single pump is recommended.Sizethe pump to the equivalent foot of head and the total BTU load of all units
combined.The discharge of the pump is to be connected to a spud man-
ifold for proper distribution of water flow to each individual unit.This manifold should be at least 18”-24”above the pump outlet.For
independent control of the seawater pump from each unit, use a pump
relay panel (PRP).
Notes:
Contact the Dometic Corporation - Environmental Systems’Applications department for AC pumps larger than P711.
(1) E lectrical and mechanical specifications for 50-60Hz pumps are rated at 60Hz.Operating a 50-60Hz pump at 50Hz will reduce the pump head by 30% and the GPM by 17%.Do not operate 60hz only pumps at 50Hz.
(2) Ignition protected.
(3) Head calculation required for system is dependent on number and size of unit(s), length of hose, use of 90
o elbows and the height of the unit(s) above the pump.Please refer the the Marine Air Systems’pump sizing guide or consult the Applications department.
(4) GPM flow is rated at indicated pump head.
(5) Capacities given are determined using an average of 3 GPM per ton (12,000 BTU/Hr) at given GPM and head, and are rated for direct expansion (DX) AC systems only. In the interest of product improvement, specifications and design as outlined herein are subject to change without prior notice.
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