Hayward Spa Blower - Blower Sizing for Air Channel; Example; Number of Holes; Blower Sizing - Water Jets

USE ONLY HAYWARD GENUINE REPLACEMENT PARTS
Page 8 of 12 Spa Blower ISSPB Rev-A
a. Example:
An 8 ft. in-ground spa with a water depth of 38 inches is located 45 feet away from the equipment. There are 6 -
90 degree turns and 2 - 45 degree turns. Calculation of total water pressure is as follows:
1. Water height in spa = 38”
2. 45 feet of supply line = 4.5 inches
3. 6 - 90 degree turns and 2 – 45 degree turns = 3.5 inches
Total water height is 46" of water pressure (inches H2O).
This spa would require a 1.5 hp blower – see chart below.
BLOWER SIZE VOLTS AMPS INCHES O
F
WATE
R
("H2O)
1 HP 120
/
2
4
0 6.
7/3
.
5
UP TO
4
0" O
F
PRESSURE
1.
5
HP 120
/
2
4
0 8.0
/4
.0 UP TO
5
0" O
F
PRESSURE
2.0 HP 120
/
2
4
0 10.0
/
6.0 UP TO 6
5
"O
F
PRESSURE
b. Number of Holes
The number of holes in the spa floor and seats determine the size of your air blower. For a 1.0 hp blower the
total hole area should be .85 square inches, for a 1.5 hp blower the hole area should be 1.2 square inches, and
for a 2.0 hp blower the total hole area should be 1.5 square inches. The chart below shows some common hole
sizes. For example: you could drill as many as 70 - 1/8 inch holes with a 1.0 hp blower.
Hole diameter in Hole area in s
q
uare
1
/
8 .012
3
3/16
.0277
1
/4
.0
49
1
Total hole area = (number of holes) x (hole area)
5. Blower Sizing – Water Jets
Air blowers are commonly used to supercharge or boost hydro therapy jets located in the wall of the spa. The
water jets are normally designed with a venturi fitting which allows the water and air to mix at the jet. By
connecting all the venturi fittings together back to the blower supply line, you can increase the amount of air
mixed with the water. In a well planned system adding a blower makes a dramatic difference in jet action.
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A
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U