Error Code 64 is displayed only when the pre-mix unit is operating in Hybrid Hot Mode. This error occurs when the unit fails to detect flow during a period where the unit is operating the circulator.
Verify that the circulation pump and circulation flow sensor are properly connected to the wire harness, and that the wire harness is securely connected to the circuit board.
In addition, if the circulation pump has not operated for an extended period of time, the pump may have become seized. Inspect the pump and take the appropriate corrective action to restore normal operation.
Descale procedures can be found in the installation/owner’s manual, on our Help Site and on our YouTube Page along with a general maintenance video.
For further technical assistance call 866-766-7489 or use our Contractor Locator to find a local service representative.