Errors

Boiler type Alpine Alp105B

Error code 4

Cause:

Supply high limit

Sage2.1 supply sensor detected temperatures in excess of 210°F.

Solution:

-Heating load at time of error was far below the minimum firing rate of the boiler.
-Defective system circulator or no flow in primary loop.
-Defective boiler circulator, no flow or insufficient flow in boiler loop.
-Control system miswired so that the boiler operation is permitted when no zones are calling.