Which type of ballast pump is better?
A very common question we get asked is, "What are the differences between aerator class pumps and reversible pumps?" More often the question is actually phrased more along the lines of "Which type of pumps is better". This article will outline the pros and cons of each type of pump, as well as some potential applications to help you decide which one is best for your boat ballast application.
Aerator Ballast Pumps
First off, let's take a look at aerator class pumps. These pumps can also be referred to as Livewell or cartridge type pumps. Fundamentally, the most important thing to know about an aerator class pump is that they only run in one direction, so to fill and drain a ballast location will require the use of two separate pumps, one for the fill side and one for the drain side.
The other thing to be aware of when it comes to aerator class pumps is that they are not a self priming pump, which means that they're not capable of pulling water into where the pump is; they can only push water out from where the pump is located. That means there are more constraints regarding the placement of aerator pumps within the ballast system to ensure that everything functions correctly.
As long as those constraints are met though, aerator pumps are a very reliable option because of the fact that they have a rigid impeller which doesn't contact the walls of the housing of the pump. As a result, the pump is not susceptible to run dry damage, is incredibly durable and they're also quite inexpensive for the amount of speed that they provide.
One thing to note when it comes to real world applications of aerator pumps is that typically the rated capacity of the pump will be substantially higher than the real world capacity of the pump. When we add in things like back pressure from the additional fittings in the system and the amount of work that the pump will have to do to overcome gravity to lift the water to the top of the ballast bag.
In an aerator pump based ballast system, typically the fill pump will be mounted directly at the intake from the water source and will connect to the top of the bag, so it fills through the top of the bag while the drain pump would be mounted directly to the bottom of the ballast bag and will drain through a thru-hull connector on the side of the boat. Additionally, you'll need a separate vent overflow connection, leaving you with three total connections to the ballast bag and the accompanying hose and fittings necessary to support those connections.
Reversible Ballast Pumps
Flexible vane impeller pumps, on the other hand, which are also known as positive displacement pumps or reversible pumps, are a pump that can be run in two directions by simply switching the current, the direction of the current going to the pump. So if you provide positive on one wire and negative on the other wire, the pump will run in one direction and if you reverse that, the pump run in the opposite direction.
Because reversible pumps both fill and drain, we only needed to make a single connection to the bottom of the ballast bag to service that bag. A secondary connection on the top of the bag is used as the vent overflow connection that is attached to the thru-hull connector on the side of the boat, which means only two connections are needed in a ballast system that uses a reversible ballast pump.
Pump Comparison
When it comes to installing a ballast system, the first decision to make is which type of ballast pump you plan on using. This decision will impact the rest of the system design and layout, as well as the number of components required for proper functionality. There are pros and cons to each type of pump, which we have summarized in the following table:
Impeller | Aerator | |
---|---|---|
Pros | Reversible, acts as a check valve, self-priming, fewer components in system | Affordable, durable, compact |
Cons | Cost more, need run dry protection, limitations to pump placement. | Two pumps required, installation limitations, require additional check valves |
Example | Jabsco Ballast Puppy, Johnson Ultra Ballast Pump | Attwood T800, Attwood T1200 |
So there's a quick overview of the differences, pros and cons between reversible ballast pumps and aerator class pumps. If you have any additional questions, feel free to contact a product expert by email support@wakemakers.com, phone at (888) 338-6085, or by using our live chat feature.
Post Comments
0 Item(s)