Description of Operation
In each of these special purpose UVC modes, if the space temperature drops below EHS and the Emergency Heat function is enabled, the UVC is forced into the Emergency Heat mode (see “Emergency Heat Mode (Super State)” on page 16) and then return once the Emergency Heat function is satisfied.
Table 9: Actions during special purpose unit modes
Action | Indoor air fan | Outdoor air | Exhaust fan | |
(IAF) | damper (OAD) | output | ||
| ||||
Pressurize | High | 100% Open | Off | |
Depressurize | Off | Closed | On | |
Purge | High | 100% Open | On | |
Shutdown | Off | Closed | Off | |
Energy hold off | Off | Closed | Off |
Pressurize Mode
When in Pressurize mode, the UVC uses the IAF, OAD, and exhaust output as needed to pressurize the space. The UVC stops all normal heating and cooling but does allow emergency heat if required. The pressurize mode can only be accessed via a network connection.
Depressurize Mode
When in Depressurize mode the UVC will use the IAF, OAD, and exhaust output as needed to depressurize the space. The UVC stops all normal heating and cooling but does allow emergency heat if required. The
Purge Mode
When in Purge mode, the UVC uses the IAF, OAD, and exhaust output as needed to purge the space. The UVC stops all normal heating and cooling but does allow emergency heat if required. The purge mode can only be accessed via a network connection or with ServiceTools for MicroTech II Applied Terminal Unit Controllers (ATS).
Shutdown Mode
Shutdown mode is the equivalent of the Off mode, but is an Off mode forced by a network connection. When in Shutdown mode, the UVC stops all normal heating, cooling, ventilation (OA damper is closed), and fan operation. By default emergency heat is not be used during the shutdown mode, however, the UVC can be configured (Emergency Heat Shutdown Configuration) to allow emergency heat operation during shutdown mode. The shutdown mode can be accessed via a network connection, a binary input to the UVC, or with ServiceTools for MicroTech II Applied Terminal Unit Controllers (ATS).
WARNING
Shutdown mode and energy hold off mode are a “stop” state for the unit ventilator. It is not a “power off” state.
Energy Hold Off Mode
The UVC supports an energy hold off state, which when active forces the UVC to stop all normal heating, cooling and ventilation. Typically used by a network connection to force the UVC to cease heating, cooling and ventilation when conditions exist where heating, cooling and ventilation are not required or desired. Energy hold off mode is very similar to shutdown mode except that energy hold off always allows emergency heat if required. The energy hold off mode can only be accessed via a network connection or with ServiceTools for MicroTech II Applied Terminal Unit Controllers (ATS).
22 | McQuay OM 751 |