B26, boiler safety limit, or external limit wired to terminals 3 and 4 is open.
Check for these possibilities.
• Heating load at time of error was far below the minimum firing rate of the
boiler
• Defective primary pump or no flow in primary loop (Piping Method 1)
• Control system miswired so that boiler operation is permitted when no zones
are calling
that is from the install manual.
Check for these possibilities.
• Heating load at time of error was far below the minimum firing rate of the
boiler
• Defective primary pump or no flow in primary loop (Piping Method 1)
• Control system miswired so that boiler operation is permitted when no zones
are calling
that is from the install manual.
