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...or give us a call at 304-645-2310 (USA) | ||
| Supplying leisure products to the public at wholesale prices for over three decades! | |||
What's in a pump?
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When purchasing a pump for their spa or hot tub, few people are ever aware of the
profound range that's available, even within a single
manufacturer's offering. The problem is that a pump is rated by its "wet end"
(i.e. the "pump" itself - the part that actually moves the water), rather than
by the motor that drives the wet end. Moreover, the pump is rated under "no
load" conditions, which relates very little to real world situations. Therefore, one particular "1 HP pump" might offer triple the performance and durability (or more) than another "1 HP pump". There are two specifications that will help you to determine the value of the pump you select - service factor and performance under a load. The "load" is the resistance that the water experiences as it leaves the pump and travels through the plumbing. Contrary to what might seem logical, there is greater load (or "head" as it's described within the industry) from a run of pipe that passes through many elbows, than there is in a run of pipe that must traverse a vertical height. This is because elbows offer great resistance (via friction) to the water's flow, but much of the energy lost as the water is sent, for example, from the basement up into the tub in the backyard, is regained as the water is pulled by gravity back down from the tub to the pump. "Feet of head" should not be confused with the distance between the tub and the pump, though they do partly relate to one another. For example, 100' of straight pipe might only represent 10' of head (it depends on the diameter of the pipe and the amount of water it carries), but you'd lose nearly a foot of head for each 90 degree elbow in this line. A filter and heater might each add 5' to 10' of head, etc. Any more of a discussion regarding "friction head", or resistance to the water's flow, is beyond the scope of this web page, but suffice to say that it is unrealistic to compare various pumps' performances under no load, and that a performance chart should be consulted to see what happens to the pump's output in real world circumstances. For this reason, below you will see performance charts on the models of pumps that we have placed on our equipment pricing page. Anyone selling pumps that is unwilling to provide such data should not be trusted. There are some really "cheap" pumps out there, and you could easily find a "3 HP pump" with less performance than that of full service 1 HP pump that we sell! Another indication of the quality of a pump is the "Service Factor" (or SF) of the particular pump and motor combination. This figure can be expressed as number, such as something like "1.0" or "1.6", but the industry mostly uses terms like "Full Service Factor" and "Unity Service Factor". If you take a 1 HP wet end, for example, and you match it with a 1 HP (full rated) motor, then you have what we call "Unity Service". For the sake of durability, most respectable manufacturers will oversize the motor for any particular wet end. If you buy a 1 HP pump from us with full service, it will actually have a 1.5 HP motor. As a rule of thumb, you will typically find that a pump with unity service generally has the same motor as a full service pump of the next smaller size. For example, a 1.5 HP unity service pump is likely to have the very same motor as a 1 HP full service pump. Service Factor is a direct representation of the durability of the wet end/motor combination. If a Unity Service Pump can be expected to last five to ten years, then all things being equal, you can expect twice this life span from a Full Service pump. Conversely, a "budget pump" might have such an undersized motor that it has a lowly service factor of only 0.5 and might only last for two or three years at best. Remember, "you get what you pay for", but not all vendors are likely to be forthcoming with the specifications you'll need to determine the value of the pumps that they are offering, especially if the value is not too good. Below, you will see the appropriate performance charts for most of the pumps that are shown on our equipment pricing page, as well as an explanation of how to compare them. Despite the higher price, as you'll see, the better value is the better pump, if you want your spa or hot tub to have the best performance and you want your pump to last the longest. As you compare prices, please keep in mind that all the pumps on our equipment pricing page are two speed, and that the difference in price between a single speed and a dual speed pump is usually lost quickly in the added energy expenses of running the pump on high speed during the filtration cycle. Also, all of our Full Service pumps have a trap (hair and lint strainer), whereas all of the Unity Service pumps listed on our web site do not. If the pump is after the filter, then the trap is not required, however if the pump is before the filter (which is more efficient), then a trap is a necessity. Note that Unity Service pumps are all also available with a trap if need be. Please also note that if you would prefer a different brand, we have access to wholesale prices on just about every model of every brand pump presently being made. |
