Troubleshooting guide

Page 12 of 28 / OM 931-3
Fan Operation during most Modes,
Faults and Shutdowns
The MicroTech III unit controller allows fan operation during
most modes, faults and shutdowns to facilitate maximum
space comfort and control. However, the fan does not operate
during brownout condition. During most modes, faults, or
shutdowns the fan will operate under the following condi-
tions:
1. In occupied modes, the thermostat inputs G, Y1, or W1
are energized.
2. In unoccupied modes, the thermostat input W2 is
energized.
Operation with the High Speed Jumper
■ The MicroTech III unit controller includes a high-speed
jumper terminal labeled JP1 to speed system check out
and trouble-shooting. See Figure 2 on page 6 for JP1
location.
Note: This jumper is intended for Daikin McQuay factory unit
testing and should only be used by trained service
technicians as several timing functions are reduced to
speed system check out.
■ Disconnect power to the unit when installing or removing
the high-speed jumper.
■ The high speed jumper should only be used for a short
period of time for testing of the unit’s operation by a
trained service technician. The jumper must be removed
for normal unit operation.
■ If the jumper is left on after system check out, the unit
may be damaged.
Priority of Faults and Modes
The MicroTech III unit controller is congured with mode
and fault priorities. Table 3 illustrates that the lower the prior-
ity level number, the higher the priority of the fault or mode.
There are some exceptions to this priority list. For example,
tenant override has no affect on occupied modes.
Table 3: Priority Level of Faults and Modes
Priority Level Mode or Fault
1 Emergency Shutdown Mode
2 Brownout
3 High Pressure
4 Low Pressure
5 Low Temperature
6 Tenant Override Mode
7 Unoccupied Heating Mode
8 Occupied Heating Mode
9 Condensate Overow
10 Occupied Cooling Mode
Table 4: MicroTech III Unit Controller Status LED's
Mode / Fault
Status LED’s Thermostat Alarm Light
Yellow Green Red Output-Terminal “A”
Occupied, Bypass,
Standby, or Tenant Off On Off Energized
Override
Unoccupied On On Off Energized
Condensate Overow On Off Off De-energized
High Pressure 1 Fault Off Off Flash De-energized
Low Pressure 1 Fault Off Off On De-energized
Low Temperature 1 Fault Flash Off Off De-energized
Brownout
Off Flash Off De-energized
Emergency Shutdown Off Flash Off De-energized
Room/Return Air or Low
Flash Flash On De-energized
Temp Sensor 1 Failure
Service Test Mode
On On Off De-energized
Enabled
1
Serial EEPROM
On On On De-energized
Corrupted
Network “Ofine”
Off Off Off De-energized
Received
1
Compressor relay/compressor terminal is labeled COMP, switched line of
the same electric input as any of the L1 terminals.
Troubleshooting the MicroTech III
Unit Controller
To avoid electrical shock, personal injury or death, be sure
that field wiring complies with local and national fire, safety,
and electrical codes, and voltage to the system is within the
limits shown in the job-specific drawings and unit electrical
data plate(s).
Power supply to unit must be disconnected when making
field connections. To avoid electrical shock, personal injury or
death, be sure to rigorously adhere to field wiring procedures
regarding proper lockout and tagout of components.
DANGER