Return temp higher than supply
The Control is reading a return sensor temperature higher than the supply sensor temperature. Condition must be present for at least 75 seconds for this error code to appear.
-Flow through boiler reversed. Verify correct piping and circulator orientation.
-No boiler water flow. Verify that system is purged of air and that appropriate valves are open.
-Sensor wiring reversed.
-Supply or return sensor defective.
