Jacuzzi Z Builder Series Mechanics And Repair page 52

Sn3. Water Temperature Sensor has failed. Replaced.
OH. Overheat protection enacted. Caused by the heater actually getting hot, a
failed OH Sensor, or the board. Option is to replace.
Pd. Power failure. Unit is on battery backup if available.
COOL. Water temperature is below 20 degrees from what the topside is set for.
This is normal when spa water is changed with cold water. Otherwise is warning
that spa is not at temperature set point.
ICE. Freeze Protect. Spa is going into panic mode and will turn all pumps on
periodically to avoid freezing.
ECON: If available, spa is in Economy Mode. Unit will go up to 20 degrees below
the temperature set. It is NOT a more economical setting. It is usually set when
you are on vacation and will not be using the spa.
STAN: Standard mode. All functions work.
Spa Topsides with a DIAL Temperature Control
The heater light will flash to indicate what the failure is. I have found these codes
only slightly trustworthy but they are suppose to mean the following:
Brief flashing red heater light
Meaning: Board sees a failure in water pressure. This failure can be:
The pressure switch itself, or
The pump has failed, or
The PC board has failed not seeing the pressure switch properly.
Even flashing:
Meaning: Board sees an overheat situation. If the water hasn' t overheated, then
this failure can be: