Jacuzzi Z Builder Series Mechanics And Repair page 16

The heater itself is simply an element that heats. Electrical current enters it and
slows down. This slowing down causes the element to heat. As water flows by the
heated element the temperature is transferred from the element to the water. It's
typical to heat 1-6 degrees per hour. The spas that operate on 110-130vac
typically heat 1-2 degrees per hour. Spas that operate on 220-240vac heat 5-6
degrees per hour.
The various generations of Heater Assemblies:
First, there are several generations of heater designs that Jacuzzi used. The first
generation was a horizontal heater with a pressure switch that screws into the
backside and the high limit clips against the heater. It was the most popular
designed used throughout their production.
The next production used a similar horizontal heater that also had the pressure
switch screwed into the top middle and the OH Sensor inserted into the heater
assembly.
On the Pinnnacle Model the heater used is a similar model to the first production
model but longer.
On the Z112 models they used a short horizontal heater on the top of the control
box.
On many of the last Platinum models they began using the vertical heater to the
left of the control box and a small circulation pump in front of the control box.
When the electronic spas were first introduced, I attempted to remove the heater
assembly with the control box remaining attached. The heater is held in place by
two "L" straps. Each strap is held to the control box by a bolt. One end of the
strap is attached to the back of the control box and the other underneath. I would
remove the back bolts and then attempt to loosen the lower bolt. These weren't or
rarely were easily accessible and I would end up with a lot of frustration and
bloody knuckles. I would even try leaving the lower bolts tight and bend the straps
and remove the heater assembly but this would distort the straps so when you
bend them back they would not align with the holes.