This error is generated when the External Low Water Cutoff is installed and the water level in the boiler is low. When this code is displayed, the boiler will not respond to a demand for heat. The bottom line of the display indicates the status of the pump. The pump will remain on when this error is displayed.
IF EXT LWCO is installed:
- Check boiler feed water system. Ensure it is supplying make-up water to the boiler system.
- Be sure all air is bled from the system.
- Check for leaks in the boiler and system piping and repair as necessary.
- Inspect low water cutoff wiring for damage and repair as necessary.
- Ensure EXT LWCO has power applied to the power input terminals.
- Press Reset button on LWCO. If error reoccurs, replace EXT LWCO.
IF EXT LWCO is NOT installed:
Inspect the jumper from terminals 20 and 21 on the Field Connection Board for damage or loose connections.
