Hayward HCB110BTA, Troubleshooting Manual

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Common Error Codes
LP
LP
HeatPro Display
Summit Display
LP on Display
LP is an indication the low pressure switch is open. The
switch opens when the refrigerant pressure drops below
80PSI, and will automatically reset at 120PSI.
Sustained ambient temperatures below 21
⁰F
will cause the LP
error, however once the ambient temperature rises above
40 ⁰F the switch will close automatically.
Troubleshooting LP
The most common cause of LP on display is a loss of refrigerant pressure from a leak in the
refrigeration system. If refrigerant pressure is below 80PSI at your access port there has been a
significant loss of charge. Thoroughly leak check the system with an electronic leak detector, or
alternatively pressurize the system with dry
nitrogen and use a liquid leak detector such as “Big Blue”. If a leak still cannot be located inject UV
dye into the system and recharge to full charge. Allow several days to as long as several leaks
weeks -depending on apparent
severity of leak-, with normal heat pump operation for the dye to leak out with the refrigerant, and
return with UV light to determine leak location.
Once leak is located: Repair leak, evacuate system to a minimum 500 micron vacuum, and
recharge to factory charge (on data plate)
Other causes of LP error code
An intermittent LP code can be caused by a bad fan motor or capacitor. Check capacitor and
motor.
Bad LP switch. Check refrigerant pressure at access port. If pressure is above 120PSI check the
continuity of LP switch. Switch should be closed. If open replace switch. The LP switch is a screw
on style and does not require removing refrigerant charge to change. Be sure to use a thread
sealant when installing new switch. Always use a back up wrench when installing new pressure
switch.
If switch is closed ,
but LP is displayed check wires to switch for breaks. If no breaks are found
replace control board.
LP Switch
Note blue wires.
LP switch common to all
R-410A heat pumps