Pressure Switch Replacement Section
This switch detects the amount of pressure in the system and allows the heater
to activate when heat is requested.

If the switch doesn’t detect the proper amount of pressure, the heater will not
come on and a display message will appear on the topside panel.

Display Message:
“FL” or “Flo”—indicates a possible pressure switch problem or water flow
1. Turn the power off.
2. Prepare a new pressure switch by wrapping Teflon tape around the threads.
(Take care not to cover the hole as the pressure will not be detected.)
3. Close the gate valves (if equipped) or drain the spa (if not equipped with gate
4. Disconnect the wires from the old switch. (Note the placement of the wires).
5. Carefully unscrew the old switch counterclockwise from the heater manifold.
6. Place the new pressure switch in the heater manifold and tighten. (Do not
over tighten.)
7. Replace wires and turn power back on.

  • The 1.0 psi pressure switch is designed for pumps of 2 hp or less.
  • The 2.0 psi pressure switch is for pumps of 4 hp or more.
  • The error code FL means that the pressure switch remains closed while
    the pumps turned off. This may have resulted in a dry fire. Test the heater
    element continuity with the tester.
  • The pressure switch measures both water and air pressure.
  • The pressure switch is a normally open switch
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Technicians and is general information on the Repair and
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