KB-16 A comparison matrix of the various unit control type selection for the air handling profile

Content

 Unit Control Type Name  Primary Cooling  Primary Heating Cooling over Heating   Heating over Cooling  Heating and Cooling  Space Temperature Control Slave 
Description The unit is used for the primary cool air for terminal units, similar to built-up air handler for VAV's. Only the cooling mode, cooling setpoints, and resets are used. The unit will enable and use the heating equipment to maintain the discharge temperature. The unit is used for the primary heating air for terminal units, similar to an outside air feed for room fan coils. Only the heating mode, heating setpoints and resets are used. The unit will enable the cooling equipment to maintain the discharge temperature. The unit is used for the primary heating or cooling air for terminal units, similar to a roof-top unit with VVT's. The preference will be to cater to the terminal unit's calling for cool. A 20% greater heating call will cause a switch to heating, even in the cooling mode. The unit is used for the primary heating or cooling air for terminal units, similar to a roof-top unit with VVT's. The preference will be to cater to the terminal unit's calling for heat. A 20% greater cooling call will cause a switch to cooling, even in the heating mode. The unit is used for the primary heating and cooling air for terminal units, similar to a dual duct system. Both heating and cooling systems are use simultaneously, with separate heating and cooling resets. The unit is used for the primary heating and cooling air for a single zone. The heating and cooling will be used as needed to maintain space setpoints. No terminal unit information is used. The unit is used for as a slave to another main unit. The heating and cooling will be used as called by the master unit.
Uses Cooling Systems Yes – Cooling is the main objective Yes – Only for raising the discharge temperature to the cooling setpoint Yes – Only when child zones are calling for  active cooling Yes – Only when child zones are calling for  active cooling Yes – at all times  Yes – Only when the terminal load calls for cooling Yes – If the master calls for cooling 
Uses Heating Systems Yes – Only for lowering the discharge temperature to the heating setpoint  Yes – Heating is the main objective  Yes – Only when child zones are calling for  active heating  Yes – Only when child zones are calling for  active heating  Yes – at all times  Yes – Only when the terminal load calls for heating  Yes – If the master calls for heating 
Does Cooling Setpoint Resets Yes  No  Yes  Yes  Yes  Yes  Yes 
Does Heating Setpoint Resets  No  Yes  Yes  Yes  Yes  Yes  Yes 
Does Modulating Fan Control  Yes  Yes  Yes  Yes  Yes  Yes  Yes 
Does Static Pressure Resets  Yes  Yes  Yes  Yes  Yes  No  No 
Uses Economizer  Yes  Yes  Yes  Yes  Yes  Yes  Yes 

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