Variable Air Volume Applications (Single Zone VAV)
Single Zone VAV
The indoor motor will vary the indoor motor speed to optimize minimum fan speed for the cooling demand in all modes (Economizer Only, Economizer +1st Stage Cooling, or Economizer + 1st/2nd Stage Cooling).
The ECA continues to modulate the economizer damper open/closed to keep the mixed air temperature that is calculated by the RTRM.
If economizing is not possible, the ECA drives the damper to the minimum position setpoint when the indoor fan relay (F) is energized and allows mechanical cooling operation.
When the unit is equipped with the optional fan failure switch, wired between terminals J7-5 and J7-6 on the RTOM, the RTRM will stop all cooling functions and produce an analog output if the fan failure switch (FFS) does not open within 40 seconds after a request for fan operation. When the system is connected to a remote panel, the “SERVICE” LED will flash when this failure occurs.
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.