Error 8 indicates that a thermostat has lost communications with the system. The zone loses the room temperature measurement of an associated Lite thermostat, leaving the zone disabled to generate demand. Check from your Blueface thermostat whether the Lite thermostat has lost communications.

If your installation is equipped with wireless Lite thermostats see: ( My thermostat displays Error 8 (I have wireless Lite thermostat) ).

If your installation is equipped with wired Lite thermostats, follow the instructions below:

Check that the main control board's polarity and the thermostat's connectors are correct (as shown in the image). The power feed voltage (measurement between the positive and the negative poles) should be 12 Vdc.

If the wiring is correct and the problem persists, check the voltage between the poles (A /-) and (B /-). The voltage should be between 0.5 Vdc and 2 Vdc and the two measurements should be similar (be balanced); in other words, if the voltage of A/- is 0.9 Vdc, the voltage of B/- may vary between 0.8 Vdc and 1.0 Vdc. If the voltages are not within these ranges, there is a problem in the wiring or one of the parts is defective. Get in touch with the Technical Department ( Open a new ticket ).

If the voltages are correct, check whether the thermostat in question has the microswitch that corresponds to the associated zone selected. If not, activate it by lifting up the tab to the desired value.

Remember: Should it be necessary to change the zone number, first reset the thermostat and initiate the association sequence ( How do I change the damper associated to a zone equipped with a Lite thermostat? ).