Unoccupied Mode

Facilities Services is continuing to expand its implementation of unoccupied mode for building heating and air conditioning systems at the University of Idaho.

As the Moscow campus has a wide verity of building types and ages, it is not possible to apply the same unoccupied strategy to all buildings. Buildings at the University with Air Handling Units that are controlled through the campus Energy Management System (EMS) are generally scheduled to switch between occupied and unoccupied mode on a fixed schedule. A typically occupied mode is Monday through Friday, 6 AM to 6 PM. The actual schedule will vary for each building depending on the regular scheduled operating hours for a particular building. Generally the occupied mode schedule will begin one hour prior to, and end one-hour after the posted building open / closed hours. If anyone needs to use any area served by these systems during scheduled unoccupied hours they can override the unoccupied mode at any time. (See below for instructions) The system will then switch to occupied mode for a period of 3 hours.

For buildings with electronic controls the unoccupied override button is located on the local Zone-Sensor, which is mounted on a wall somewhere near the area controlled by that senor. The zone-sensor is a small off-white plastic box (see photo) that looks like a thermostat. The newer models have the word "Siemens" on the lower right, and the unoccupied override button is located just below the digital display of the room temperature. This button, which is the only active button, has a symbol of a sun and moon on it. For older models the word “Powers” is printed on the front, and the unoccupied override button is a very small (1/8” diameter), white button on the left-end of the top-face of the sensor. Note the occupied / unoccupied mode is a system level control, so pushing the override button on any zone sensor on the system will cause the entire system to revert back to occupied mode for three hours. As a zone sensor is not located in every room (this is especially true for office zones) you may have to go to a neighboring room or corridor to find a zone sensor.

When the system is in unoccupied mode and the override button is pushed, the system will go into occupied mode for three hours. As it takes some time for the room temperature to recover after occupied mode is initiated, you may want to push this button at least one-half to one hour prior to any event occurring during unoccupied hours.

Facilities Services will also be adding a scheduled unoccupied mode for many Heating Ventilating and Air Conditioning (HVAC) systems around campus. Since most of our buildings have some irregular after-hours use, it is our policy to always have a method to locally override the unoccupied mode. All new and recently upgraded systems have Siemens controls, so the description of the override button above will apply in most situations. Currently we have implemented the unoccupied control strategy only in buildings with this type of electronic controls, so if you are in an older building that does not have this type of system your building is not yet affected.