System Installation Guide
18
69-2490 —03

TheEconomizercangreatlyreduceenergycostsifconfiguredproperly.Insome

climatesthecoolingsystemmayrunhundredsofhours,whenit maynotbe

requiredtomaintainindoorcomfort.Insomeconditions,ventilationwithoutdoor

aircanachievethesamelevelofcomfortatlower cost.Tablesbelowexplainhow

theEconomizerfeaturemaintainscomfortwhileminimizingcosts.

Occupied Heat/Cool/Fan running
ON
Occupied temporarily Heat/Cool/Fan running
Occupied Heat/Cool/Fan NOT running
Occupied temporarily Heat/Cool/Fan NOT running
Pre-occupancy purge Fan running
Unoccupied Cooling system running
Unoccupied temporarily Cooling system running
Standby Cooling system running
Unoccupied Cooling system NOT running OFF
Unoccupied temporarily Cooling system NOT running
Standby Cooling system NOT running ON
Non-programmable Fan running
Non-programmable Fan NOT running OFF
Occupied
ON
Occupied temporarily
Temperature overrides
Unoccupied
OFF
Unoccupied temporarily
Standby
Non-programmable
Economizer and TOD operation (ISU 2220 ) Commercial use only
Thermostat Mode
Thermostat Mode
Equipment Operation
A-L/A terminal:
Economizer
A-L/A terminal:
TOD
69-2490_B.indd 18 7/13/2011 1:42:00 PM