Spa Blower Installation

How a Spa Blower Operates on a Spa

The operation of a blower on a portable spa is fairly simple to understand. In the animation to the left, the blower is blowing air into the spa – seems simple enough. But there is much engineering to getting a spa blower to work correctly, quietly, efficiently and safely on a portable spa. Remember that the blower is about 30-40 inches below water level! Typically, two types of safety designs are used to protect the blower from water damage:

Hartford Loop

The “loop” marked #1 is called a Hartford loop (trivia: was named after the Hartford Insurance company who invented it!). The loop should be already in your spa plumbing!

Spa Blower Check Valve

The fitting marked #2 is the check valve. This is typically a secondary level of protection for the spa blower. The protection is from the water backing up into the blower and causing it to fail. Check valve failure is the #1 cause of spa failure due to water intrusion into the spa blower.

Spa Blower Installation on a Portable Spa

Our Tranquility Spa Blowers are designed ONLY for use and installation on portable spas. For in-ground spas, typically these use outdoor duty blowers (sometimes buried in the ground) For blowers for in-ground spas, Polaris Pool Products makes a good product. (www.polarispools.com)

How the Air Gets into the Spa

Spa manufacturers used three methods for introducing the air into their spas. The air is injected into the spa by:

Air Channel integral to the Spa – If you have this method, you will see a series of holes drilled into the spa – usually at the seats and floor. The spa was manufactured with a channel system where by the air from the spa blower is channeled to these holes.
Air Injectors – In this method, air is ported to individual “jets”. If you have this system, you will see “salt shaker” fittings in the seat area or floor. Each of these fittings has an individual air line going to it.
“Turbo-Charged” – In these spas, the manufacturer designed the blower system to augment the air venturi action on your spa jets. Air is forced out of the spa jets (from the main pump) and blasts across the spa when your spa pump is operating.
Hybrid System – Sometimes, there is a valve that switches from “Turbo-charge” to one of the other systems described above

How to Size a Spa Blower

Chances are that your spa blower is sized correctly. So for general information, a spa blower is sized according to the total diameter of the discharge ports into the spa and the depth of the lowest air inlet. The blower needs to overcome this “pressure” caused by the depth of the water in order to operate correctly.
Some basic rules of thumb:
A. 1HP Tranquility Blower can handle water depth of 36-40″
B. 1-1/2HP Tranquility Blower can handle water depth of 40+”

But depth of water is only one consideration. To properly size the blower, you must add up all the holes discharging air into the blower.
The hole size corresponds to square inches per the following chart.

Hole Size versus Square Inches of Air Inlet

Hole Size

Area of Hole in Square Inches

Calculating Total Square Inches of Air Injection

Now you simply multiply the number of holes by the corresponding square inches of the air hole size in your spa. For example: if you count 65 (1/8″) holes, the total square inches of air inlet into the spa is 65 holes x( .0123 sq.in./hole) or 0.80 square inches total. (Total Air Injection = # of air holes X Area of each hole per the chart)
1 HP Tranquility Blower = .75 to .85 square inches total
1-1/2 HP Tranquility Blower = 1.1 to 1.25 square inches total.

In the above example (.80 square inches total), the proper size blower would be a 1 HP Tranquility Blower.

Our Hot Line :

Tranquility Spa Blowers