Document LTP0101 rev 2.1f

 

Adjusting Water Pressure Switch

Adjust water pressure switch when heat pump attempts to operate without water flow.

Before attempting any adjustments confirm the following :

  • The filter is clean.
  • Filter pump is operating.
  • The valves are set to direct the appropriate amount of water through the heat pump. See "Water Flow Rates"
  • FLO is displayed (or displays intermittently).

 

WARNING

Failure to heed the following may result in injury or death.

 

  • Water Pressure Switch adjustment procedure to be performed by experienced service personnel only; procedure must not be attempted by individuals lacking adequate electrical and mechanical experience.

NOTICE

Failure to heed the following may result in damage to equipment.

 

  • If the heat pump continues to operate after a water pressure switch adjustment, deactivate equipment and perform additional troubleshooting.

  1. Remove heat pump access panel.
  2. Locate the water pressure switch. It will be outside and along the bottom edge of the electrical enclosure. Exact location varies by model.
  3. Activate filter pump.
  4. Apply power to heat pump.

  5. Slowly rotate the adjustment wheel on the switch. Keep turning the wheel until the heat pump indicates it is receiving water. The display will no longer display the FLO code.

  6. Deactivate filter pump. If correctly adjusted, the heat pump will deactivate and the display will show the FLO code.
  7. Re-install heat pump access panel.
  8. If the heat pump continues to operate without water flow, the installation of a grid flow switch may be required.
    • This can become necessary if the heat pump is installed below the elevation of the body of water to be heated or cooled. The standing pressure from the water can cause the water pressure switch to activate when the circulation pump is off. Therefor a water flow switch must be used in place of a water pressure switch to determine if incoming water is being sent to the heat pump. See "Grid Flow Switch (# 0040S)"
  9. If heat pump continues to operate without water flow, contact AquaCal®.