Daikin Enfinity Installation And Maintenance Manual page 28

Supplemental electric heat control
The supplemental electric heating option provides
additional stages of heating that can be used in
conjunction with compressor heating, or exclusively if the
compressor is not available for heating.
General rules
Supplemental electric heater and the compressor
•
may operate simultaneously.
Minimum compressor ON and OFF timers do not
•
apply to electric heat control.
Operation
Fan main output: will turn ON when:
• Any auxiliary heat output is energized.
• For 30 fixed seconds after all auxiliary heat outputs
have been de-activated.
Electric heat outputs: are allowed to energize when
either condition exists:
• Inter-stage ON timer must be expired.
• Compressor is not available for heating.
When compressor is available
• Auxiliary heat stage #1 output energizes upon activation
of heating – stage #3.
• Auxiliary heat stage #2 output energizes upon activation
of heating – stage #4.
When compressor is unavailable
• Auxiliary heat stage #1 output energizes upon activation
of heating – stage #1.
• Auxiliary heat stage #2 output energizes upon activation
of heating – stage #3.
■ Boilerless heat control –Turns on the heater when the
entering water temperature is less than setpoint (default
is 55°F), the temperature set point is adjustable through
the network.
For geothermal applications the heater turns on when
the entering water temperature is less than setpoint
(default 28°F).
Note: In both cases the compressor is shut down.
■ Short cycle protection & random start – After power
cycle or deactivation of certain alarms, or when leaving
the unoccupied mode, a new random compressor start-
delay time between 300 and 360 seconds is generated.
The random start timer prevents compressors in
different units from starting simultaneously. Compressor
minimum OFF 360 sec) and compressor minimum ON
(180 sec) timers prevent compressor short cycling.
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■ Unoccupied mode – A simple "grounded" signal
between terminals U and C (no power source required),
puts the unit into the unoccupied mode for night setback
operation.
■ Inter-staging timer – A default value of 5 minutes
between staging of compressors, this feature minimizes
short cycling of compressors and improves comfort.
■ Override mode – A switch on the deluxe automatic
changeover thermostat can be activated during the
unoccupied mode to put the unit back into the occupied
mode for two hours for after-hours heating or cooling.
■ Motorized valve/pump restart – The IV/PR (H8)
terminals on the The MicroTech III unit controller are
used to energize (open) a motorized valve or start a
water pump to get water circulating prior to starting
the compressor on call for heating or cooling. Lead
compressor operation shall be delayed a minimum of 45
seconds, after the motorized valve/isolation valve output
energizes to allow for supply water flow.
■ Brownout protection – The MicroTech III unit
controller measures the input voltage and will suspend
compressor and fan operation if the voltage falls below
80% of the unit nameplate rated value. Two external
LED status are generated and an output is available to
a "fault" LED at the thermostat.
■ Emergency unit shutdown – A simple grounded
signal puts the unit into the shutdown mode. Remote
shutdown is provided so that when properly connected
to a water loop controller or remote switch, the
emergency shutdown input can be used to shut
down the water source heat pump. Compressor and
fan operations are suspended, and an a unique two
external LED status is generated.
■ Condensate overflow protection (cooling &
dehumidification modes only) – The MicroTech III
unit controller incorporates a liquid sensor at the top of
the drain pan. When the unit senses a high condensate
water level for 60 consecutive seconds while in the
cooling or dehumidification modes the unit enters
the "Off Alarm" machine state. The dehumidification
or cooling mode operation will immediately be de-
energized as well as the pump output.
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LARGE VERTICAL WSHP IM 1059-12
ontrols