American Standard UV05 manual OA temp sensor Space humidity, Economizer enable

Table 19: How economizer enable/disable tests are selected

Table 18: Economizer enable/disable tests defined

Temperature Comparison with Enthalpy Comparison requires both an optional OA humidity sensor and an optional IA humidity sensor.

Note –

Temperature Comparison with Enthalpy Comparison Economizer (optional)

If the optional Leading Edge economizer function is selected, the unit ventilator is provided from the factory with both the IA humidity and OA humidity sensors, which are used along with the IA temperature and OA temperature sensors to calculate IA enthalpy and OA enthalpy. In this case, the UVC is factory set for Economizer Strategy 2 and uses the Temperature Comparison with Enthalpy Comparison Economizer function.

Note –

Temperature Comparison with OA Enthalpy Setpoint Economizer requires an optional OA humidity sensor.

Description of Operation

• Expanded (optional)—Temperature Comparison with OA Enthalpy Setpoint Economizer (Strategy 1)

• Leading Edge (optional)—Temperature Comparison with Enthalpy Comparison Economizer (Strategy 2)

Temperature Comparison Economizer (default)

If the default Basic economizer function is selected, the unit ventilator is provided from the factory without the optional IA and OA humidity sensors. In this case, the UVC is factory set for Economizer Strategy 1—the UVC automatically detects that no OA humidity sensor is present and adjusts to use the Temperature Comparison Economizer function.

Temperature Comparison with OA Enthalpy Setpoint Economizer (optional)

If the optional Expanded economizer function is selected, the unit ventilator is provided from the factory with the optional OA humidity sensor, which is used along with the OA temperature sensor to calculate OA enthalpy. In this case, the UVC is factory set for Economizer Strategy 1 and uses the Temperature Comparison with OA Enthalpy Setpoint Economizer function.

Tests	Economizer	Enable test	Disable test
	enable/disable tests
A	OA temp set point	EffectiveOATemp < (EconOATempSetpt – EconTempDiff)	EffectiveOATemp >= EconOATempSetpt
B	IA/OA differential temp	EffectiveOATemp < (EffectiveSpaceTemp – 3.6°F – EconTempDiff)	EffectiveOATemp >= (EffectiveSpaceTemp – 3.6°F)
C	OA enthalpy set point	EffectiveOAEnthalpy < (EconOAEnthalpySetpt –	EffectiveOAEnthalpy >= EconOAEnthalpySetpt
		EconEnthalpyDiff)
D	IA/OA differential	EffectiveOAEnthalpy < (EffectiveSpaceEnthalpy –	EffectiveOAEnthalpy >= EffectiveSpaceEnthalpy
	enthalpy	EconEnthalpyDiff)

Economizer	Space temp sensor	OA temp sensor	Space humidity	OA humidity sensor	Economizer enable/
strategy			sensor		disable tests
All	Unreliable	Don’t care	Don’t care	Don’t care	OA damper closed
	Don’t care	Unreliable	Don’t care	Don’t care	OA damper closed
Basic	Reliable	Reliable	Don’t care	Unreliable	Test B
	Reliable	Reliable	Don’t care	Reliable	Test C
Expanded	Reliable	Reliable	Don’t care	Reliable	Test C and Either
					Test B or Test A
	Reliable	Reliable	Reliable	Reliable	Test D and Test B
Leading Edge	Reliable	Reliable	Unreliable	Reliable	Test B
	Reliable	Reliable	Reliable	Unreliable	Test B
	Reliable	Reliable	Unreliable	Unreliable	Test B
	Note:	The hard-wired sensor and the equivalent input must both be unreliable for the value to be considered
		unreliable.

McQuay OM 751 33