Unit mode priority – American Standard UV05 User Manual
Page 23
McQuay OM 751
23
Description of Operation
Unit Mode Priority
The UVC uses the network variables and binary inputs listed in Table 10 and Table 11 to
determine the current unit mode. Special purpose UVC unit modes have higher priority than
the normal UVC unit modes as shown in the tables.
Each table lists the highest priority items on the left to the lower priority items to the right. The
right-most columns indicate unit operation as a result of the left-most columns. The term
“Don’t care” in these tables implies that another network variable or binary input to the left
has a higher priority.
Table 10: Special purpose UVC unit mode priority
Table 11: Normal UVC mode priority
Priority result
Emergency override
input
1
Remote shutdown
binary input
Energy hold
off input
1
Energy hold
off output
2
Unit mode
output
2
Actual UVC action
Normal
3
De-energized
4
Normal
Normal
See the normal
UVC mode priority (Table 11)
Energy hold off
Energy hold off
Off
Off
Energized
5
Don’t care
Energy hold off
Off
Off
Pressurize
Don’t care
Don’t care
Don’t care
Off
Pressurize
De-pressurize
Don’t care
Don’t care
Don’t care
Off
De-pressurize
Purge
Don’t care
Don’t care
Don’t care
Off
Purge
Shutdown
Don’t care
Don’t care
Don’t care
Off
Off
1. Network input.
2. Network output.
3. Normal indicates the UVC power-up condition.
4. De-energized indicates that the contacts connected to this binary input are open.
5. Energized indicates that the contacts connected to this binary input are closed.
Priority result
Application override
input
1
1. Network input.
Unit mode override
input
1
Unit mode output
2
2. Network output.
Normal (Auto)
3
3. Normal (Auto) is the normal UVC power-up state.
Normal (Auto)
3
Heat
Cool
Emergency heat
Heat
Heat
Cool
Cool
Night purge
Night purge
Off
Off
Emergency heat
Emergency heat
Fan only
Fan only
Heat
Don’t care
Heat
Cool
Don’t care
Cool
Night purge
Don’t care
Night purge
Off
Don’t care
Off
Emergency heat
Don’t care
Emergency heat
Fan only
Don’t care
Fan only