Instruction manual
www.DaikinApplied.com 37 OM 751-4
desCrIptIon of operatIon
External Binary Output 3
This output can only be used to signal exhaust fan operation (default) or operate an
auxiliary heat device.
Exhaust Fan ON/OFF Signal
This relay output provides one set of Normally Open dry contacts that can be used to
signal the operation of an exhaust fan. When the OA damper opens more than the En-
ergize Exhaust Fan OA Damper set point, then the relay output signals the exhaust fan
ON (contacts closed). When the OA damper closes below this set point, the relay output
signals the exhaust fan OFF (contacts open).
Auxiliary Heat Signal
This relay output provides one set of Normally Open dry contacts that can be used to
operate an auxiliary heat device. The UVC by default is congured to operate a Normally
Open auxiliary heat device (de-energize when heat is required), such as a wet heat valve
actuator with a spring setup to open upon power failure. However, the Auxiliary Heat
Conguration variable can be used to set the UVC to use a Normally Closed auxiliary
heat device (energize when heat is required), such as electric heat.
Table 20: Auxiliary heat start/stop calculation
Start/Stop Calculation
Auxiliary heat starts when:
Primary Heat PI-Loop = saturated high (100%)
for more than two minutes
AND
EffectiveSpaceTemp ≥ EffectiveSetpoint – Auxil-
iaryHeatStartDifferential
Auxiliary heat stops when:
EffectiveSpaceTemp ≥ (EffectiveSetpoint –
AuxiliaryHeatStartDifferential) +
AuxiliaryHeatStopDifferential