One zone is not heating and the other does not turn the air handler on.

There is an air purge system.The encyclopedia is free.An air purge system is used to clean the equipment before it is turned on.The equipment’s function is not affected by the surrounding environment.

What is a Zms sensor?The S 1-ZMS is a duct mounted sensor that is used with the S1 MMZ, S1- MMH3 and S-1 ZMS4 Zone Control Panels.The heating or cooling equipment will be locked down when the supply air temperature goes above or below the heating set point.

Capacity control of heating and cooling equipment is provided by the discharge air temperature sensor.It is only used with Honeywell.

The air is trapped in the top of the system.A reduction in the surface area of the condenser will cause a high pressure.There is a leak in the low side of the system.