Replacing A Microtech Iii Unit Controller - Daikin MicroTech III Installation And Maintenance Manual

CAUTION
The MicroTech III unit controller incorporates static sensitive
devices . A static charge from touching the device can damage the
electronic components . To help prevent damage during service,
use static discharge wrist straps . Static discharge wrist straps are
grounded to the heat pump chassis through a 1M ohm resistor .
Replacing a MicroTech III Unit
Controller:
1 . Connect wrist strap to unit .
2 . Remove faulty board and place on static protected
surface .
3 . Remove replacement unit controller from static
protected bag .
Table 5: Jumper settings and descriptions
Jumper
JP1 Mode
JP2
Fan operation
JP3
Freeze Protection
(See Warning)
JP4 Freeze Fault Protection
Set point adjustment range only applies to net-
JP5
work controls with a room temperature sensor
JP6
Room control type
JP7 Compressor heating source
JP8 I/O expansion module
WARNING
Proper antifreeze/water solution is required to minimize the
potential of fluid freeze-up. Jumper JP3 is factory set for water
freeze protection with the jumper open. Operation at fluid
temperatures below 32°F with anti-freeze protection requires JP3
to be field configured for the jumper closed. If unit is employing
a fresh water system (no anti-freeze protection), it is extremely
important that JP3 jumper setting remains in the open position
(factory default setting) in order to shut down the unit at the
appropriate water temperature to protect your heat pump from
freezing . Failure to do so can result in unit damage, property
damage and will void unit warranty .
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Description
Open for normal operation mode
Shorted for service/test operation mode
Open for continuous fan operation, when not in unoccupied mode .
Shorted for cycling fan operation
Open for water freeze protection
Shorted for systems with anti-freeze protection
Open for none
Shorted to enable freeze fault protection based on Leaving Water Temperature (LWT)
Open for adjustment range of -5 .0° to +5 .0°F
Shorted for 55° to 95°F adjustment range
Open for thermostatic room control
Shorted for room temperature sensor control, MicroTech III only .
Open to enable compressor heating
Shorted to disable compressor heating
Open when I/O expansion module is not needed
Shorted when I/O expansion module is required
Note: Do not touch circuit board; hold by edges.
4 . Holding unit controller in grounded hand, install
controller in unit .
5 . Insert faulty board in empty static bag for return .
Figure 2: Location of configuration jumpers on the unit
controller
7
M t III u C
ICro eCh nIt
Options
ontroller
OM 1149-5