Errors

Boiler type MPO-IQ84

Error code ErP91

Cause:

Communication Error

Solution:

Communications error has been detected.
Remove all devices from the Enviracom connections, 3-pin plug and screw terminals "1-2-3".
If the error does not clear within one minute, measure the voltage on terminals "2" and "3".
If the voltage across terminals "2" and "3" is between 20VAC and 30VAC, replace control.
If it is outside of that range, review boiler wiring. There should be approximately 24VAC across "2" and "3".