Start-Up; Operation; Thermostat Inputs; Electric Heat Controls - Daikin MicroTech III Installation And Maintenance Manual

The MicroTech III unit controller's valve or pump request
terminal [IV/PR (H8)] is an output signal to external devices
to allow water flow as required by the heat pump. The IV/
PR (H8) terminal follows compressor operation inversely if
connected to the normally open terminal and simultaneously
when connected to the normally closed terminal . The IV/
PR (H8) terminal can be used as a signal to an external
pump or valve to enable flow to the unit. The compressor
start is delayed for 45 seconds after the IV/PR (H8) output is
energized .
Table 12: IV/PR(H8) terminal and compressor operation
IV/PR(H8) Compressor On
Normally Open
Normally Closed

Operation

Thermostat Inputs

Waterside Economizer/ Dehumidification
• The Waterside Economizer/Dehumidification input
(TB1-1) on the I/O expansion board, when energized
from the thermostat, enables Waterside Economizer
or Dehumidification operation depending on jumper
configuration.

Electric Heat Controls

W4
• The W4 (TB1-2) terminal enables the second stage
of electric heat .

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 .
OM 1149-5
Compressor Off
24 VAC 0 VAC
0 VAC 24 VAC
Operation:
Fan Main Output: will turn ON and the Fan PWM signal
will be at "Auxiliary Heat" duty cycle 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 #4 .

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.
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tart up
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