Troubleshooting
Problem
Cause
Solution
Display will not illuminate.
No power.
Improper wiring.
Improper voltage.
Check circuit breaker and wiring connection.
Check polarity and wiring.
Ensure voltage is 115V or 230V.
HI or LO setting will not
change.
Differential attempted is below 10 psi
or above 55 psi.
Minimum cut-in reached.
Maximum cut-out reached.
Differential cannot be less than 10 psi or greater
than 55 psi. Adjust as necessary.
LO cannot be set below 10 psi.
HI cannot be set above 80 psi.
Pump will not reach
cut-out (HI).
HI setting greater than pump rating.
Insufficient prime (above ground
pumps).
No water to pump.
Pump or line blockage.
Fixture open or leak in plumbing.
Reduce HI setting to within pump capability.
Prime pump as directed by manufacturer -
use manual operation mode.
Check shutoff valves.
Remove obstructions.
Determine cause of water flow and remedy.
Pump rapid cycles.
Pressure tank too small.
Differential too narrow.
Waterlogged pressure tank.
Improper tank air charge.
Improper wiring.
Size tank per manufacturer’s literature.
Spread range via HI or LO setting.
Replace tank.
Charge as instructed by manufacturer.
Check proper wiring to “line in”, L1 & L2.
Pump will not start.
No power.
Guardian CP error encountered.
Faulty pump.
Improper wiring (Guardian CP or pump).
Check circuit breaker and wiring connections.
See error chart below.
Contact pump manufacturer.
Check wiring per manufacturer’s instructions.
Water flow stops before
cut-in.
Tank precharge too high.
Adjust precharge per manufacturer’s instruction.
Display reads upside-down. Mounting position may vary.
Press
5 6
together for 3 seconds and screen
will rotate 180 degrees.
Code
Reason
Action
Solution
E1
Rapid cycle.
Excessive amp draw.
Pump continues to operate.
See “Pump Rapid Cycles” above.
Have pump checked for
proper operation.
E2
Low water cut-off.
Running pressure below 10 PSI.
Pump shuts off.
Auto restart after 60 min.
(A) Determine cause of
low-suction
(B) Check Wiring
(C) Inspect pump
E3
Improper voltage.
Pump shuts off.
Auto restart when voltage
connected.
Restore voltage to proper
range.
Unit will monitor voltage
until it returns to normal. Pump
will restart automatically.
E4
Electrical disturbance.
Pump shuts off.
Disconnect power for one
minute to reset. If error
persists, contact Amtrol
Technical Support.
Error Codes
To reset switch at any time: Press
5
6
buttons simultaneously for 5 seconds.
© 2022 Worthington Industries Inc.
Part #: 9046-0001 (11/22)
One or more features of this product are covered by U.S. patents, visit www.amtrol.com/patents for more information.
1400 Division Road, West Warwick, RI USA 02893
T: 800.426.8765
www.amtrol.com
