Troubleshooting guide
Page 4 of 28 / OM 931-3
Table 1: MicroTech III Unit Controller Terminals & Descriptions
H1 - 1 24 24 VAC Power Input
H1 - 2 C 24 VAC Common
H2 - 1 SL1 Fan Output - Switched L1
H2 - 2 Blank Terminal
H2 - 3 N Fan Neutral
H3 - 1 HP1-1 High Pressure Switch 1 Input Terminal 1
H3 -2 HP1-2 High Pressure Switch 1 Input Terminal 2
H4 - 1 Discharge Air Temp Common
H4 - 2 Discharge Air Temp Signal
H4 - 3 Leaving Water Temp Common
H4 - 4 Leaving Water Temp Signal
H5 - 1 1 I/O Expansion Board Common (Gnd)
H5 - 2 I/O Expansion Board Common (Gnd)
H5 - 3 I/O Exp Board +5 VDC
H5 - 4 I/O Expansion Board SPI CE1
H5 - 5 I/O Expansion Board SPI CLK
H5 - 6 I/O Expansion Board SPI OUT
H5 - 7 I/O Expansion Board SPI IN
H5 - 8 I/O Expansion Board +12 VDC
H5 - 9 I/O Expansion Board 24 VAC
H5 - 10 I/O Expansion Board 24 VAC
H5 - 11 Spare
H5 - 12 Spare
H6 - 1 1 Condensate Overow Signal Input
H6 - 2 Low Temp 1 Sensor Common
H6 - 3 Low Temp 1 Sensor Signal
H6 - 4 Low Pressure Switch 1 Source Voltage
H6 - 5 Low Pressure Switch 1 Signal
H6 - 6 Reversing Valve 1 Common
H6 - 7 Reversing Valve 1 Output
H7 - 1 1 Dummy Terminal
H7 - 2 Dummy Terminal
H7 - 3 Red LED Output
H7 - 4 Green LED Output
H7 - 5 Yellow LED Output
H7 - 6 Red-Green-Yellow LED Common
H8 - 1 1 Isolation Valve/Pump Request Relay N/O
H8 - 2 Isolation Valve/Pump Request Relay N/C
H8 - 3 24 VAC Common
H9 - 1 1 Return Air Temperature Signal
H9 - 2 Return Air Temperature Common
TB1 - 1 1 Room Sensor LED Output
TB1 - 2 2 Fan Mode / Heat-Cool-Auto Input
TB1 - 3 3 Setpoint Adjust Input
TB1 - 4 4 Room Temperature Sensor / Tenant Override
TB1 - 5 5 DC Signal Common
Test-1 R 24 VAC
Test-2 W2 Heat Stage 2 Input
Test-3 W1 Heat Stage 1 Input
Test-4 Y2 Cool Stage 2 Input
Test-5 Y1 Cool Stage 1 Input
Test-6 G Fan
TB2 - 1 R 24 VAC
TB2 - 2 A Alarm Output
TB2 - 3 W2 Heat Stage 2 Input
TB2 - 4 W1 Heat Stage 1 Input
TB2 - 5 Y2 Cool Stage 2 Input
TB2 - 6 Y1 Cool Stage 1 Input
TB2 - 7 G Fan Input
TB2 - 8 O Tenant Override Input
TB2 - 9 C 24 VAC Common
TB3 - 1 E Mark IV Emergency Shutdown Input
TB3 - 2 U Mark IV Unoccupied/Occupied Input
L1 - 1 L1 - 1 Line Voltage Terminal 1
L1 - 2 L1 - 2 Line Voltage Terminal 2
L1 - 3 L1 - 3 Line Voltage Terminal 3
N1 N1 Neutral Terminal 1
N2 N2 Neutral Terminal 2
N3 N3 Neutral Terminal 3