Daikin MicroTech, Operation And Maintenance

Page: 18 / 78

OM 1280-2 • MICROTECH UNIT CONTROLLER 18 www.DaikinApplied.com
Description of Operation
Emergency Heat Mode (Super
State)
The Emergency Heat mode is provided for situations where the
UVC is in a mode that does not normally allow heating, such
as Off, Cool, Night Purge, or Fan Only. If Emergency Heat
mode is enabled, the UVC can automatically force itself into
the Emergency Heat mode from Off, Cool, Night Purge, Fan
Only, Purge, Pressurize, De-pressurize, and Shutdown. Units
with two-pipe chilled water configuration do not have primary
or secondary heating devices. In the event that the Emergency
Heat mode is entered the UVC will use auxiliary heat if
available. See “Auxiliary Heat Signal” on page 41.
Full Heat State
The Full Heat state is the “normal” state that the UVC goes
into when Emergency Heat mode is active. It is activated
when the space temperature is lower than the EHS. When
Emergency Heat mode becomes active, the UVC goes into
100% heating until the space temperature raises to the EHS
plus a fixed differential. In the Emergency Heat mode, the
space fan is set to high speed, and the OA damper closes. If
the UVC automatically forces itself into the Emergency Heat
mode from another mode (e.g., Cool, Fan Only, etc.), then
the UVC returns to the appropriate unit mode once the space
temperature rises to the EHS plus a fixed differential.
The UVC monitors the DAT to ensure it does not exceed
DAHL. If the DAT does exceed DAHL, then heating is set to
0% for a minimum of 2-minutes (fixed) and until the DAT drops
36°F (20°C) fixed differential below DAHL.
Figure 10: Emergency Heat (Super State)
Emergency Heat
Mode
Full Heat
Mode
Is SpaceTemp
> (EHS+5.4F)
Enter from:
Network Input
Automatically from Off, Cool, Night
Purge, Fan Only, Purge, Pressurization,
De-pressurization or Shutdown
Yes
No
If entered
automatically
return to Off
or Fan Only
Mode. If
entered by
network input
go to Normal
Heat Mode