Jacuzzi Z Builder Series Mechanics And Repair page 15

Chapter TWO HEATER
Function:
The heater is a simple device. Electricity is applied to the heater element.
Because the element is made to resist the current but not completely, the
heater's resistance causes the element to glow. The result is heat.
Overview:
The heater does just what's name says, heats the water. Generally on Jacuzzi
designed spas you will not notice noticeably warm water coming out of the jets
because of the design of the jets. On Jacuzzi Whirlpool design, the water passes
through the heater and then a manifold disperses the water to many jets and thus
spreading out the amount of heater water. On a few designs including the current
Jacuzzi Premium spas it's common to have the water pass through the heater
and then into the spa using only a couple jets. In doing so you can feel the heater
water entering the spa. As to the better design, it's a personal preference.
The two basic flow methods start the same way; the water is pulled from the
lower part of the spa (called suction fittings) and one or two assemblies with filters
designed to pull water from the top of the spa. The theory is this will draw water
from upper and lower and therefore keep a thorough water movement.
From these two points the water is pulled through the circulation pump or #1
pump, depending on the design of your spa. Jacuzzi mostly used the #1 pump
method of their spas but later Platinum spas did have a circulation pump.
Then the water passes through the heater. You have 2 types of heaters for a
Jacuzzi Whirlpool. The most common is the horizontal heater attached to the
bottom or bottom backside of the control box. Jacuzzi Whirlpool at the end of
their spa production did begin to use a vertical heater with a circulation pump.
This heater is attached to the left side of the control box.
From the heater the water flows to a manifold that dispenses the heated water
throughout the spa.