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A NEW BRUSHLESS DC MOTOR DRIVEN PUMP now makes FWC much more affordable!

Diagram of Cooling System

{Electric Antifreeze Pump}

The BLDC Pump

Ever since we introduced the concept of a Freshwater Cooling System with an electric antifreeze circulating pump, I have been continuously researching new and better pumps to improve performance, reliability, longevity and cost. With the development of Brushless DC electric motors and their application to water pumps, a steady stream (no pun intended) of new offerings has been introduced. The early problem with these new pumps was their cost. Our first offering was the Bosch pump which gave excellent performance but its cost still kept FWC out of reach of many Atomic 4 owners. Now, we are pleased to intergrate the BLDC DC60G Brushless DC Pump into our Electric FWC system. And, it comes with a 2 YEAR WARRANTY!

The image to the right shows this new antifreeze pump utilized in the installation of the Indigo Electronics AT-4CE Fresh Water Cooling System on an Atomic 4. The most significant and unique aspect of this system is that this new heavy duty, seal-less, brushless antifreeze pump, manufactured by BLDCPump Co, can be mounted in-line in most any convenient location. This feature insures that this system can be installed on any vessel. Note that the suction and discharge connections are both 3/4 NPT male connections. This configuration was chosen to allow the installation of a cast brass/bronze 3/4 NPT ell at one or both locations to provide the most flexibilty for proper hose routing yet still have great coolant flow. Physically, the pump is about 3.5" in diameter (plus the discharge connection) and about 5.5" long including the suction hose connection.

Any FWC Cooling System (actually antifreeze cooled) requires that there be two pumps in the system. One is the raw water pump and one is the antifreeze pump. The "normal" FWC System uses a mechanical pump for both applications. We now offer a new BRUSHLESS DC electric pump for the antifreeze circuit. With this new type of electric motor in the pump there is no "failure" anxiety over brush wear/failure as the pump/motor is rated at more than 10000 hours .

The existing mechanical pump remains the raw water pump. However, the pump discharge is re-routed to provide cold raw water to the new Heat Exchanger instead of to the engine block. The new centrifugal antifreeze pump circulates antifreeze through the block, head, manifold and Heat Exchanger. Why an electric antifreeze pump? First and foremost, this pump can easily be mounted in any engine compartment. It mounts "in-line" and just needs to be below or inline with the Heat Exchanger outlet. Secondly, the electric pump consumes about 1/2 as much power as the mechanical pump. Our own testing shows the pump consumes about 5.8 amps at 13.6 VDC. We have been operating a pump in a simulated A4 setup, with our electronic ignition system running at the same time, and it has not "skipped a beat yet." Thus far we have logged over 1060 hours, most of them at 13.6 VDC coming right off the ignition coil, the worst case scenario for "dirty power". Per the manufacturer of the pump, estimated service life is over 10000 hours.

The single most important factor for long life of the typical pump motor is the voltage at which it operates. This is NOT the case with this Brushless DC Pump. Utilizing a feature know as "Constant Power Consumption" the speed of this brushless motor remains constant with an input voltage ranging from 9 to 15VDC. For this reason there is no need to have a Ballast Resistor to manage the voltage level and no concern about overloading the motor with either too high or too low voltage.

This centrifugal pump is a higher pressure, higher flow pump than most typical centrifugal pumps used in this application as can be seen in the curves to the right. Having said that, the output flow of the pump is directly related to the condition of the flow path within the engine. Three "System" curves are shown on the graph to the right. A "System" curve is a graph which indicates the resistance to flow that the coolant has to overcome in order to flow through the engine. The three curves represent A4s with different configurations and conditions. The "Red Curve" represents a saltwater cooled A4 with the "As Built" configuration of hoses and fittings. That is to say that the standard 1/2" hose barb inlet to the block, the 3/8" hole in the "diverter cap" inside on the side cleanout plate and the standard 1/2" hose barb fittings between the thermostat housing and the manifold. Additionally, the curve assumes considerable rust and scale within the manifold causing considerable flow resistance. This "Red Curve" condition will provide sufficient cooling in cool water environments but may struggle in very warm Summer waters. The "Yellow" and "Green" System Curves represents engines with different flow improvement modifications. The "Yellow" configuration has a 5/8" hose between the thermostat housing and manifold, and an acid flushed block, head and especially manifold. The "Green" configuration goes the extra steps to enlarge the inlet fittings and diverter cap as well as the installation of an Indigo thermostat. If you are in the process of overhauling your engine, it is certainly a good idea to enlarge the inlet fittings to 5/8" hose at least and to enlarge the holes in the diverter cap.

You have probably have never heard of BLDCPump Co. and quite honestly I had not either until I found them on the Internet. They are a Chinese manufacturer who specializes in small brushless DC pumps for aquariums, solar applications, and Electric Vehicles. One of their big customers is BYD Auto Co. http://www.byd.com and a similar pump is used to circulate coolant through the EV battery. They currently produce about 10000 pcs of this model per year. If you care to check them out, go to https://www.bldcpump.com/ and you can learn all about their many product offerings.

All Kits come with a pump, Power Relay, Heat Exchanger, mounting brackets, coolant recovery bottle, and hose barb fittings with hose clamps. The pump itself comes complete with a power cable, all hose fittings, clamps, hardware and mounting brackets. The only material not provided is 1/2, 5/8 and 3/4 inch heater hose for the connection of the various components as each installation is very much different with regard to the location of the heat exchanger.

The pump is available by itself for $150.


Heat Exchanger (Incl with all kits)

{Heat Exchanger, Recovery Bottle, Mounting Bracket}

The Heat Exchanger is an all copper "shell and tube" design with 4 passes. Raw water circulates through the tubes and antifreeze circulates around the tubes. The Heat Exchanger is designed to operate totally full of antifreeze at a pressure of about 5 psi with an antifreeze recovery bottle provided to collect and return antifreeze to the system. A bracket is provided for mounting the Heat Exchanger to a convenient vertical surface but it can also be mounted at up to a 45 degree angle if space does not permit a vertical installation. The current thermostat configuration is still utilized which includes the bypass hose which runs from the side plate "T" connection to the thermostat outlet housing under which the thermostat is housed. As with Raw Water Cooling, it is critical that the internal bypass "boss" in the outlet housing be as designed and not wasted away after years of salt water attack. (it may be worth while to look at yours if you have not done so in a while. The "boss" control surface which the thermostat closes against should be flat with no craters in it and no more than 7/16" below the housing gasket surface). An improved Thermostat Kit, which eliminates the current thermostat and bypass hose, is offered as an option ($115 with purchase of FWC, $130 otherwise). An additional Product Improvement is the Belt Tension Device which makes adjusting the alternator belt tension a snap.

Start-Up Accessories

As a result of the lessons learned since introducing the Indigo Electronics AT-4CE kit, each kit will now be shipped with a Pump Pressure Gauge Assembly and a Coolant Filter Assembly. The gauge is to be installed between the pump discharge and the 1/2" hose going to the inlet to the block. Pressure readings obtained have been found to be an excellent means of evaluating the flow of coolant through the engine and allowing you to compare your readings to known systems. The Coolant Filter has always been a suggested complement to a new system but by having one provided, you can be assured of cleaning the debris out of your system with both filter media and a magnet and avoid frustrating overheating situations during initial operation. Below are images of the Pump Pressure Gauge Assembly and the Coolant Filter Assembly. A Core Charge of $25 and $15 respectively will be charged when the kit ships. Once your system is fully functional, you may elect to return one or both items for a full refund. If you decide to keep then, that is fine as well.

SMALL DIESEL APPLICATIONS: Most any of the small auxiliary diesel engines found in sailboats can utilize this System. The discussion above is worded around the Atomic 4 but is nonetheless applicable to small diesels. The existing raw water pump is similarly re-routed to supply raw water to the Heat Exchanger and the new electric pump is installed so as to circulate antifreeze through the block and manifold. Please call with any additional questions.

Thank you for your interest in the Indigo Electronics AT-4CE Cooling System. Fresh water cooling not only prevents deterioration of the block, head and manifold, but it allows the engine to run at higher temperatures (170-180 F) promoting improved combustion and performance.

Download Thermostat Installation Instructions

Call today for Credit Card orders or send check/money order to:

Indigo Electronics, Inc.

105 Pipe Kiln Court
Williamsburg, VA 23185

Order Today. You never knew sailing could be so much fun!
1-800-428-8569 toll free
or 757-593-8569

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