Bosch Boiler Error Codes
Complete guide to Bosch boiler error codes with safety information and troubleshooting steps.
Important Safety Notice
Bosch boilers use alphanumeric error codes. "E" codes indicate errors, "F" codes are faults, "A" and "P" codes are alerts.
Only reset the system once. Repeated resets can cause damage.
Call Now: 778-909-5731Safety Level Key
SafeSystem protected, low risk
CautionMonitor and call technician
DangerCall technician immediately
Common Bosch Error Codes
Error Code EA
Flame Detection Fault
What You Can Check
- •Check gas supply is on
- •Verify meter reading
- •Check for gas outages
Error Code E9
Overheat - Limiting Thermostat
What You Can Check
- •Turn off unit
- •Let system cool
- •Check pump operation
Error Code A7
Low System Pressure
What You Can Check
- •Check pressure gauge (should be 12-18 PSI)
- •Look for visible leaks
Error Code F0
Internal Temperature Sensor Fault
What You Can Check
- •Note display readings
- •Cycle power
Error Code F1
Return Sensor Fault
What You Can Check
- •Check return temperature display
Error Code E1
Ignition Lockout
What You Can Check
- •Reset once only
- •Check gas valve
- •Verify power supply
Error Code P4
Water Pressure Sensor Fault
What You Can Check
- •Check actual system pressure
- •Compare to displayed pressure
Don't See Your Error Code?
Bosch has many error codes across different models. Our technicians have extensive experience with all Bosch systems and can quickly diagnose any issue.
Call 778-909-5731