Controls, Start-Up, Operation, Service and ... - Climayoreo

APPENDIX E — MODE SELECTION PROCESS (cont)
HVAC mode: ("Vent ")
— This is a normal operation mode where no heating
or cooling is required and outside air is being
delivered to the space to control IAQ levels.
HVAC mode: ("Low Cool ")
— This is a normal cooling mode when a low cooling
demand exists.
HVAC mode: ("High Cool ")
— This is a normal cooling mode when a high
cooling demand exists.
HVAC mode: ("Low Heat ")
— This is a normal heating mode when a low
heating demand exists.
HVAC mode: ("High Heat ")
— This is a normal heating mode when a low
heating demand exists.
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HVAC mode: ("Unocc. Free Cool")
— In this mode the unit will operate in cooling but
will be using the economizer for free cooling.
Entering this mode will depend on the status of the
outside air. The unit can be configured for outside
air changeover, differential dry bulb changeover,
outside air enthalpy changeover, differential
enthalpy changeover, or a custom arrangement
of enthalpy/dewpoint and dry bulb. See the
Economizer section for further details.
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NOTE: There is also a transitional mode whereby the machine
may be waiting for relay timeguards to expire before shutting
the machine completely down:
HVAC mode: ("Shutting Down ")