1. Insufficient water pressure
2. External Limit Tripped
3. Insufficient flow for Flow Switch
1. Ensure at least 15PSI at boiler outlet. Refer to Supplementary Documentation section 2.0 System Piping.
2. Indication that an external limit (wired to “LIM”) is open. Not a problem with boiler, check external limit.
3. Check plumbing, ensure circulator is operating.
