The L1 & L3 Codes are lamp replacement indicators according to the manual for the system. Please ensure that you have completed the following steps to reset the UV Time Meter.
Disconnect the Power Supply
Wait 10 Seconds
Press and HOLD the Reset Button
Connect the Power Supply while holding the Reset Button
The LED will flash for about 3 seconds
Continue to HOLD the Reset Button until the Display shows "00"
This process will reset the UV Lamp counter to 12 Months.
If this does not work then a new power supply is required. 650716-007.
Jeff - Customer Service