Aquacal SQ120R Instruction Manual page 37

HP5 Indicator
ISSUE
The heat pump has locked due to five HP (high-pressure) faults during one call for heating or cooling.
RESOLUTION
1. Deactivate then reactivate power to the heat pump to clear error.
2. Troubleshoot the high-pressure issue causing the error. See "HP Indicator" on the previous page.
LP Indicator
ISSUE
The refrigerant system's low-pressure switch is showing as open.
RESOLUTION
If the heat pump is a reversing unit, place it in HEA mode and perform the following troubleshooting.
1. Check for proper fan operation. If fan is not operating, contact AquaCal.
2. Check for obstructed air flow around the heat pump.
See "Clearances" on page 21.
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3. Check for dirty or blocked evaporator coil. See "Cleaning Equipment After Installation" on page 1.
4. Check for signs of heavy ice buildup on the coil.
LP5 Indicator
ISSUE
The heat pump has locked due to five LP (low-pressure) faults during one call for heating or cooling.
RESOLUTION
1. Deactivate then reactivate power to the heat pump to clear error.
2. Troubleshoot the low-pressure issue causing the error. See "LP Indicator" above.
OtA Indicator
ISSUE
Incoming water temperature exceeded 110° F and the unit is locked with an OtA over temperature alarm.
The heat pump will not operate until incoming water temperature drops to 100° F or lower.
RESOLUTION
1. Determine if another heat source (gas heater, solar heater, etc.) is heating water being sent directly to the heat
pump with the OtA indicator. This situation will need to be corrected before continuing.
2. Rule out an incorrect reading from the water temperature sensor. Verify existing water temperature with an
accurate thermometer. If heat pump's sensor is inaccurate, the water temperature sensor may require
replacement.
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