Applicable Systems
Greenstar GB162
Symptoms
The boiler reports an overheat protection trip. The primary heat exchanger temperature has exceeded the safety limit.
Possible Causes
- Pump failure or insufficient flow through the heat exchanger
- Air lock in the system preventing circulation
- System valve closed blocking flow
Troubleshooting Steps
- Step 1: Check the primary circulator pump operation
Pump runs and circulates water - Step 2: Bleed air from the system to remove air locks
All radiators are free of air - Step 3: Verify all system valves are open
All valves allow full flow
How to Reset
To reset: Restore flow through the heat exchanger, then press the reset button.
Source: Worcester Bosch Boiler Manual, Worcester Bosch Group
Category: Home Boiler