Troubleshooting guide

OM 931-3 / Page 3 of 28
Introduction
This installation and operation manual covers the Micro-
Tech® III unit controller for Daikin McQuay Water Source
Heat Pumps. For information on LonWorks® or BACnet®
communication modules and other ancillary components, see:
■ IM 927 - MicroTech III Water Source Heat Pump
LonWorks Communication Module.
■ IM 928 - MicroTech III Water Source Heat Pump Unit
Controller BACnet MS/TP Communication Module.
■ IM 933 - LonWorks Plug-In Software for use with
MicroTech III Unitary Controller - LonWorks
Communication Module.
■ IM 952 - Multiple Unit Control Panel (MUCP) for use
with MicroTech III Unit Controller and Mark IV Unit
Controller.
■ IM 955 - MicroTech III Water Source Heat Pump Wall-
Mounted Room Temperature Sensors.
■ IM 956 - Temperature Sensors for Units with MicroTech
III Unit Controller and LonWorks Communication
Module.
Contents
Introduction ..........................................................................3
Replacing a MicroTech III circuit board:
............................ 6
Initial Power-Up
...................................................................6
General Use and Information
.............................................7
Occupied Operation
..........................................................7
Thermostat Inputs (G, Y1, Y2, W1 and W2)
.....................7
Control Inputs (HP, LP, SLTS, COF, U, E, O)
....................7
Control Outputs {A and IV/PR (H8)}..................................8
Fan Operation
...................................................................8
Unoccupied Operation – Stand Alone
Thermostat Control
...........................................................8
Thermostat Inputs (G, Y1, Y2, W1, and W2)
....................8
Control Inputs (HP, LP, SLTS, COF, U, E, O)
....................9
Control Outputs {A and IV/PR (H8)}..................................9
Additional Operating Modes
...............................................9
High / Low Pressure Faults (HP/LP)
...............................10
Fan Operation during most Modes, Faults and
Shutdowns
.........................................................................12
Troubleshooting the MicroTech III Unit Controller
.........12
Troubleshooting the Water Source Heat Pump Unit
......14
Microtech® III Unit Controller Interface to External
Equipment
..........................................................................15
Appendix A
.........................................................................15
Operation and Maintenance of I/O Expansion Module
...15
Introduction
.....................................................................15
Features..........................................................................15
Initial Power up
..................................................................16
Operation
............................................................................17
Dual Circuit Units
............................................................17
Thermostat Inputs (Y2, W2)............................................17
Electric Heat Controls
.......................................................17
Boilerless Heat Coil Control
............................................17
Multiple Speed Fan Control
..............................................17
Three-Speed Fan Operations
.........................................17
Circuit Two, Additional Operating Modes
.......................17
Second Circuit Faults......................................................18
Appendix B
........................................................................19
MicroTech III Unit Controller with
LonWorks®
Communication Module
..................................................19
MicroTech III Controller with BACnet® Communication
Module
............................................................................20
Appendix C – Typical Wiring Diagrams
...........................21
MicroTech III Unit Controller (Standalone) –
208/230/460/575/60Hz/3-Phase
.....................................21
MicroTech III Unit Controller with Optional ECM
Motor, Desuperheater and I/O Expansion Module –
208/230/265/277/60 Hz/1-Phase
....................................22
MicroTech III Unit Controller with Optional ECM Motor,
Desuperheater, Electric Heat Coil and I/O Expansion
Module – 208/230/460/60 Hz/3-Phase
...........................23
MicroTech III Unit Controller with Optional ECM
Motor, Desuperheater, and I/O Expansion Module
208/230/460/60/3-Phase
................................................24
MicroTech III Unit Controller with PSC Motor,
Desuperheater and I/O Expansion Module for
Hot Gas Reheat Control (Unit Sizes 019-070)
208/230/60/1-Phase
.......................................................25
Controller Comparison
....................................................26