Jacuzzi Z Builder Series Mechanics And Repair page 20

Remove the 2 copper straps. First unbolt where then attach to the board. Second
remove nuts connecting the board to the heater posts. Note that the heater posts
have a nut on top and a nut built in to the bottom below the copper contact. This
is so you can put less pressure on the post when loosening or tightening. You
place a wrench on both top and bottom and loosen/tighten. If you cant reach the
lower nut, just take care when loosing/tightening so you don't bend the heater
posts.
Remove old heater. Reverse above to install new heater.
On Vertical Heater:
For spas with a vertical heater on the left side of the control box, replacement is
easy.
You must replace the complete heater.
Turn off power. You probably will have to drain the spa. Disconnect the two hoses
connected to the heater input/output. The 2 leads from the board to the heater
need to be removed. Simply remove the nuts (save for reuse) and disconnect the
leads.
Finally, the heater is held to the control box by 2-3 nuts. Remove. The heater will
disengage from the control box and replace.