Cause of error code Lockout 81

Delta T limit

Insufficient water flow. 

Solution for error code Lockout 81

- Check Fuse "B"
- Check appliance pump.
- Ensure plumbing is correct. Check that water pressure is at least 15PSI.
- Boiler heat transfer surfaces may be fouled with scale or magnetite. Clean with Fernox DS-40 Descaler and Cleanser.