Microtech 2300 - Heating Source Selection; Hydronic Heat

23
OM 1364
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HEATING SOURCE SELECTION
Heating Source Selection
Heating source selection provides a method to disable the
compressor operation when in the heating mode.
Baseboard SW7 Conguration Switch
operation
• OFF: Enables compressor operation in the heating mode.
• ON: Disables compressor operation in the heating mode.
When compressor operation is disabled in the heating mode and
electric heat is available:
• Auxiliary Heat Stage #1: output energizes upon activation of
the “Heating – Stage #1”.
• Auxiliary Heat Stage #2: output energizes upon activation
of the “Heating – Stage #4”, except on units congured for
both Waterside Economizer and Dehumidication.
When compressor operation is disabled in the heating mode
electric and hydronic heat is unavailable:
• The unit will not provide any form of heating.
Hydronic Heat
General
The hydronic heating option provides control of a two position
valve connected to a hot water coil when loop water temperature
is warm enough for hydronic heating.
• Loop water temperature is sensed by a factory installed
entering water temperature sensor located on the inlet
water line.
• Hydronic heat circuit shall be independent and substitute
the use of the compressor driven refrigeration circuit.
Operation
The Auxiliary Heat Stage #1 (H6-8) output on the MT2310 I/O
expansion board is used to open the hydronic heating valve.
• Hydronic heating setpoint allowed range is 70°F to 158°F,
with a 90°F default value.
• When Entering Water Temperature (EWT) rises above the
hydronic heating on setpoint:
• Compressor will be locked out of heating (compressor
minimum on timer applies).
• If hydronic heating is required: the pump request output is
activated; the “wait for ow” timer is canceled because the
EWT is adequate for hydronic heating; the hydronic heating
output shall energize; and the fan will turn on 30 seconds
after the hydronic heating output has been energized.
• The fan speed signal is based on the highest active heating
stage (#1 or #2). Variable speed fan operates at the
Hydronic Heat PWM speed.