McQuay WGS Installation Manual

Operation & Maintenance Data

Group: WSHP

Part Number: 910127707

Date: June 2012

OM 1149

MicroTech® III SmartSource Unit Controller with I/O Expansion Module for Single and Two Stage Water Source Heat Pump Units, Models GS/GT

I/O Expansion Module

MicroTech III SmartSource Unit Controller

Contents

Introduction ..........................................................................3

Control Boards Terminals and Connectors Descriptions 4

MicroTech III Unit Controller .............................................4

I/O Expansion Module .....................................................5

BACnet Communication Module.......................................5

LonWorks Communication Module .................................5

Replacing a MicroTech III Circuit Board: ........................... 7

Initial Power-Up ...................................................................7

General Use and Information .............................................8

Operating Modes ..............................................................8

Control Inputs (HP, LP, SLTS, COF, U, E, O) .................. 10

Control Outputs {A and IV/PR (H8)}................................10

Unoccupied Operation – Stand Alone Thermostat Control 11

Thermostat Inputs (G, Y1, Y2, W1, and W2) .................. 11

Additional Fault Modes ..................................................... 11

High / Low Pressure Faults (HP/LP) ...............................12

Fan Operation During Most Modes, Faults and

Shutdowns .........................................................................14

Faults and Modes ...........................................................14

Troubleshooting the Water Source Heat Pump Unit ......16

Microtech® III Unit Controller Interface to External

Equipment ..........................................................................17

Appendix A .........................................................................17

Operation and Maintenance of I/O Expansion Module ...17

Introduction .....................................................................17

Initial Power up ..................................................................17

Operation ............................................................................18

Thermostat Inputs ...........................................................18

Electric Heat Controls .......................................................18

Supplemental Electric Heat Control ................................18

Boilerless Heat Control ...................................................18

Compressor Heating Source Selection ...........................19

Fan Speed Control .............................................................19

I/O Expansion Module Faults and Fan Operating Modes

Tables .................................................................................20

Unit Options: ......................................................................21

Waterside Economizer ....................................................21

SmartSource Dehumidication ........................................21

Hot Gas Reheat Smart Dehumidication ........................21

Simplied Dehumidication.............................................22

Humidistat Controlled Dehumidication ..........................22

Dehumidication Only: ....................................................24

MicroTech III Unit Controller with LonWorks®

Communication Module ..................................................25

MicroTech III Controller with an Optional BACnet®

Communication Module ..................................................26

Appendix C – Typical Wiring Diagrams ......................27-35

115V, 1Ph – Model WGS, MicroTech III SmartSource Unit Controller with BACnet Communication Module (Hot Gas Reheat) (See page 28 for Service & Disconnect

Wiring) ............................................................................27

265V, 1Ph – Model WGS-WGT, MicroTech III SmartSource Unit Controller with BACnet Communication Module (Hot Gas Reheat) (See page 30 for Service & Disconnect

Wiring) ............................................................................29

208-230V, 1Ph – Model WGS-WGT, MicroTech III SmartSource Unit Controller with BACnet Communication Module (Waterside Economizer, Desuperheater, 115V Loop Pumps & 20kW Electric Heat) (See page 32 for Service &

Disconnect Wiring)..........................................................31

208-230V, 3Ph – Model WGS-WGT, MicroTech III SmartSource Unit Controller with BACnet Communication Module (Waterside Economizer, 230V Loop Pumps & 5kW Electric Heat) (See page 34 for Service & Disconnect

Wiring) ............................................................................33

460V, 3Ph – Model WGS-WGT, MicroTech III SmartSource Unit Controller with BACnet Communication Module (Waterside Economizer, 230V Loop Pumps & 20kW Electric Heat) (See page 36 for Service & Disconnect

Wiring) ............................................................................35

Controller Comparison ....................................................37

Introduction

This installation and operation manual covers the MicroTech® III unit controller for Daikin McQuay G-Series 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 Unit 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.

OM 1149 / Page 3 of 40

Control Boards Terminals and Connectors Descriptions

MicroTech III Unit Controller

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 Main Required Output – Switched L1

H2 – 2 Blank Terminal

H2 – 3 N Fan Main Required Output – Neutral

H3 – 1 HP1-1 Comp High Pressure Switch (HP1) Input Terminal 1

H3 – 2 HP1-2 Comp High Pressure Switch (HP1) Input Terminal 2

H4 – 1 1 Discharge Air Temp Sensor – Common

H4 – 2 Discharge Air Temp Sensor – Signal

H4 – 3 Leaving Water Temp Sensor – Common

H4 – 4 Leaving Water Temp Sensor – Signal

H5 – 1 1

H5 – 2

H5 – 3

H5 – 4

H5 – 5

H5 – 6

H5 – 7

H5 – 8

H5 – 9

H5 – 10

H5 – 11

H5 – 12

H6 – 1 1 Condensate Overow Signal Input

H6 – 2 Compressor Suction Temp Sensor (LT1) – Common

H6 – 3 Compressor Suction Temp Sensor (LT1) – Signal

H6 – 4 Compressor Low Pressure Switch (LP1) – Source Voltage

H6 – 5 Compressor Low Pressure Switch (LP1) – Signal

H6 – 6 Reversing Valve – Common

H6 – 7 Reversing Valve – Output

H7 – 1 1 No Connection

H7 – 2 No Connection

Connections to I/O Expansion Board

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 Room Temp Sensor & Tenant Override – Signal

H9 – 2 Room Temp Sensor & Tenant Override – Common

TB1 – 1 1 Room Sensor – Status LED Output

TB1 – 2 2 Room Sensor – Fan Mode & Unit Mode Switches

TB1 – 3 3 Room Sensor – Setpoint Adjust Potentiometer

TB1 – 4 4 Room Sensor – Room Temp Sensor & Tenant Override

TB1 – 5 5 Room Sensor – DC Signal Common

TB2 – 1 R 24 VAC

TB2 – 2 A Thermostat – Alarm Output

TB2 – 3 W2 Thermostat – Heat Stage #2 (W2) Input

TB2 – 4 W1 Thermostat – Heat Stage #1 (W1) Input

TB2 – 5 Y2 Thermostat – Cool Stage #2 (Y2) Input

TB2 – 6 Y1 Thermostat – Cool Stage #1 (Y1) Input

TB2 – 7 G Thermostat – Fan Input

TB2 – 8 O Thermostat – Heat Stage #3 (W3) Input

TB2 – 9 C 24 VAC Common

TB3 – 1 E Emergency Shutdown Input

TB3 – 2 U Unoccupied 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

Page 4 of 40 / OM 1149

I/O Expansion Module

Table 2: I/O Expansion Module Connectors/Terminals

H1 – 1 1

H1 – 2

H1 – 3

H1 – 4

H1 – 5

H1 – 6

H1 – 7

H1 – 8

H1 – 9

H1 – 10

H1 – 11

H1 – 12

H2 – 1 1 Auxiliary Heat Stage #2 Output – N/O

H2 – 2 No Connection

H2 – 3 24 VAC Common

H3 – 1 1 Ext. 24 VAC In

H3 – 2 Ext. 24 VAC Common In

H3 – 3 HGR / Waterside Economizer Output – N/O

H3 – 4 Ext. 24 VAC Common

H3 – 5 ECM Fan Motor Variable Speed Signal Output

H3 – 6 ECM Fan Motor Variable Speed Signal – Common

H4 – 1 1 Entering Water Temp Sensor – Signal

H4 – 2 Entering Water Temp Sensor – Common

H5 – 1 1 No Connection

H5 – 2 No Connection

H5 – 3 Red LED Output

H5 – 4 Green LED Output

H5 – 5 Yellow LED Output

H5 – 6 Red-Green-Yellow LED Common

H6 – 1 HP2-1 Comp High Capacity High Press Sw (HP2) Input Terminal 1

H6 – 2 HP2-2 Comp High Capacity High Press Sw (HP2) Input Terminal 2

H7 – 1 Fan Speed Table Row Select – Signal

H7 – 2 Fan Speed Table Row Select – Common

H7 – 3 Thermostat – Heat Stage #4 (W4) Input – Signal

H7 – 4 Auxiliary 24 VAC Out

H8 – 1 1 Compressor – High Capacity Output – N/O

H8 – 2 24 VAC Common

H8 – 3 No Connection

H8 – 4 Auxiliary Heat Stage #1 Output – N/O

H8 – 5 24 VAC Common

TB1 – 1 1 Humidistat Signal Input

TB1 – 2 2 Thermostat - Heat Stage #4 (W4) Input – Signal

Connections to Main Board

BACnet Communication Module

Table 3: BACnet Communication Module Connectors/ Terminals

P4 – 1 P4 GND

P4 – 2 + 5 VDC

P4 – 3 SPI SELECT (SPI Select To Communications Board)

P4 – 4 SPI CLK (Master Clock)

P4 – 5 SPI RCV (MOSI)

P4 – 6 SPI XMIT (MISO)

P4 – 7 SRDY OUT (SPI Ready To Baseboard)

P4 – 8 No Connection

P3 – 1 P3 Network Signal +

P3 – 2 Network Signal –

P3 – 3 REF

P3 – 4 Shield

LonWorks Communication Module

Table 4: LON Communication Module Connectors/ Terminals

CN_SPI – 1 CN_SPI GND

CN_SPI – 2 + 5 VDC

CN_SPI – 3

CN_SPI – 4 SPI_CLK_0 (Master Clock)

CN_SPI – 5 SPI_RX_0 (MOSI)

CN_SPI – 6 SPI_TX_0 (MISO)

CN_SPI – 7 SREADY_0 (SPI Ready To Baseboard)

CN_SPI – 8 No Connection

TB1 – 1 TB1 Network Signal A

TB1 – 2 Network Signal B

TB1 – 3 REF

SPI_SELECT1_0 (SPI Select To CommunicationsBoard)

OM 1149 / Page 5 of 40

Figure 1: MicroTech III Unit Controller & I/O Expansion Module Connectors Descriptions

Page 6 of 40 / OM 1149

CAUTION

Initial Power-Up

The MicroTech III circuit board incorporates static sensitive de-

vices. 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 1 Mohm resistor.

Pre start check list:

A random start delay time between 180 and 240 seconds is

generated at power up.

Figure 2: Location of Configuration Jumpers on the Base Board Controller

Replacing a MicroTech III Circuit Board:

1. Connect wrist strap to unit.

2. Remove faulty board and place on static protected surface.

3. Remove replacement board from static protected bag.

Do not touch circuit board; hold by edges.

4. Holding board in grounded hand, install board in unit.

5. Insert faulty board in empty static bag for return.

Table 5: Configuration Jumper Settings

Jumper Description Options

JP1 Mode

Shorted for service/test operation mode JP2 Fan operation only applies to Open for continuous fan operation room sensor control without a Shorted for cycling fan operation fan mode On/Auto switch

JP3 Freeze protection

Shorted for antifreeze protection JP4 Freeze fault protection Open for none Shorted to enable freeze fault protection based on Leaving Water Temperature (LWT) JP5 Set point adjustment range only Open for adjustment range of -5.0° to +5.0° F applies to network controls with a Shorted for 55° to 95° F adjustment range room temperature sensor

JP6 Room control type

Shorted for room temperature sensor control, MicroTech III only JP7 Compressor heating source Open to enable compressor heating Shorted to disable compressor heating JP8 I/O expansion module Open when I/O expansion module is not needed Shorted when I/O expansion module is required

Open for normal operation mode

Open for water freeze protection

Open for thermostatic room control

OM 1149 / Page 7 of 40

General Use and Information

The Microtech III SmartSource unit controller is a water source heat pump control platform used to control the heat pump in all modes of operation, including variable speed fans, two stage compressors, loop pumps, economizers, reversing valves, and all components used to control conditioned space temperature and humidity. By adding communi-

cations cards, (LonWorks or BACnet) network integration is

possible. The controller can be used with thermostat control or wall sensor control.

All MicroTech III unit controller inputs must be operated by dry contacts powered by the control board’s power terminals. No solid state devices (Triacs) may be used to operate MicroTech III unit controller inputs. No outside power sources may be used to operate MicroTech III. All units must be properly grounded per local code requirements. See the Installation

and Maintenance bulletin specic to your Water Source Heat

Pump.

Occupied Operation

The board will be in occupied mode if the unoccupied termi-

nal (U) is not shorted to ground.

Yellow Green Red Off On Off

Operating Modes

■ Start-up – The unit will not operate until all the inputs

and safety controls are checked for normal conditions.

■ Cooling mode – On an initial call for cooling, the fan

will energize at its “fan only” setting, the pump request

will engergize, the 45 second ow timer will start after the ow, compressor minimum off, and random startup

timers are expired, the compressor and fan will start at the stage 1 cooling settings. If room setpoint conditions are

not satised, the fan will operate at the stage 2 cooling settings. When the room setpoint conditions are satised,

the compressor will shut off and the fan will operate according to its “fan only” setting when enabled for continuous fan operation. If fan cycling is enabled, the fan

will turn off once room setpoint conditions are satised.

■ Dehumidication modes – There are four dehumidication modes of operation;

1. Smart Dehumidication with Hot Gas Reheat

2. Simplied Dehumidication

3. Humidistat Controlled Dehumidication

4. Dehumidication Only

See "SmartSource Dehumidication" on page 21 for details.

▪ Smart Dehumidication – Uses hot gas reheat,

a humidistat, a 2-stage thermostat and air ow

management for precise humidity control. When the

cooling and heating temperature setpoint is satised and there is a call for dehumidication, maximum dehumidication is initiated by energizing the

fan at its “fan only” setting, energizing the pump

Board LED Status – Occupied

request, engergizing the 30 second proof-of-ow

timer, energizing the hot gas reheat solenoid valve, energizing the compressor at maximum cooling, and

energizing the fan at the dehumidication setting. When the room humidity conditions are satised,

the compressor will shut off and the fan will operate according to its “fan only” setting when enabled for continuous fan operation. If fan cycling is enabled, the fan will turn off, once room humidity conditions are

satised.

▪ Simplied Dehumidication – Uses a 3-stage

thermostat and air ow management to optimize unit

capacity and fan speed for maximum latent capacity while decreasing room humidity levels. On a call for cooling, the fan will energize at its “fan only” setting,

the pump request will energize, the 30 second ow timer will start, after the ow, compressor minimum

off, and random startup timers are expired, the compressor will start at stage 1 cooling and the fan

will energize at its dehumidication setting. If the room setpoint temperature is still not satised, the fan

will be energized at the stage 1 cooling settings. If

the room setpoint temperature is still not satised, the compressor and fan will operate at the stage 2 cooling

settings. When the room temperature conditions are

satised, the compressor will shut off and the fan

will operate according to its “fan only” setting when enabled for continuous fan operation. If fan cycling is enabled, the fan will turn off, once room setpoint

conditions are satised.

▪ Humidistat Controlled Dehumidication – Uses

a humidistat and 2-stage thermostat to control room humidity levels. On a call for dehumidication, the

fan will energize at its “fan only” setting, the pump

request will energize, the 30 second ow timer will start, after the ow, compressor minimum off, and

random startup timers are expired, the compressor will start at stage 1 cooling and the fan will energize

at its dehumidication setting. If the room setpoint temperature is not satised, the fan will be energized

at the stage 1 cooling settings. If the room setpoint

temperature is still not satised, the compressor and fan will operate at the stage 2 cooling settings. When

the room temperature and humidity conditions are

satised, the compressor will shut off and the fan

will operate according to its “fan only” setting when enabled for continuous fan operation. If fan cycling is enabled, the fan will turn off once room setpoint

conditions are satised.

▪ Dehumidication Only – Uses a humidistat in the

cooling only mode. On a call for dehumidication, the

fan will energize at its “fan only” setting, the pump

request will energize, the 30 second ow timer will start, after the ow, compressor minimum off, and

random startup timers are expired, the compressor will start at stage 1 cooling and the fan will energize

Page 8 of 40 / OM 1149

at its dehumidication setting. Room temperature

conditions are not monitored or maintained. The unit

only responds to a call for dehumidication. When the room humidity conditions are satised, the compressor

will shut off and the fan will operate according to its “fan only” setting when enabled for continuous fan operation. If fan cycling is enabled, the fan will turn

off once room setpoint conditions are satised.

■ Heating mode – On an initial call for heating, the fan will

energize at its "fan only" setting, the pump request

will energize, the 30 second ow timer will start, after the ow, compressor minimum off, and random

startup timers are expired, the compressor and fan will

start at stage 1 heating settings; the reversing valve shall energize 5 seconds after the compressor turns on. If room setpoint conditions are not satised, the fan will operate at stage 2 heating settings. When the room setpoint conditions are satised, the compressor

will shut off and the fan will operate according to its “fan only” setting when enabled for continuous fan operation. If fan cycling is enabled, the fan will turn

off, once room setpoint conditions are satised.

■ Boilerless Electric Heat mode – When the entering water

temperature is below setpoint, the compressor will not be allowed to operate. On an initial call for heating, stage 1 electric heat will be energized and the fan will start at its electric heat setting. For units equipped with

2 stages of electric heat, if room setpoint conditions are not satised, the second stage of electric heat

will be energized and the fan will continue to operate at its electric heat setting. When the room setpoint

conditions are satised, electric heat will be de-

energized and the fan will continue to operate at its “fan only” setting when enabled, for continuous fan operation. If fan cycling is enabled, the fan will turn

off after 30 seconds once room setpoint conditions are satised.

■ Supplemental Electric Heat mode – On an initial call

for heating, the fan will energize at its “fan only”

setting, the pump request will energize, the 30 second ow timer will start. After the ow, compressor

minimum off, and random startup timers are expired, the compressor and fan will start at stage 1 heating

settings; the reversing valve shall energize 5 seconds

after the compressor turns on. If room setpoint

conditions are not satised, the fan will operate at stage 2 heating settings. If room setpoint conditions are still not satised, the compressor will continue

to operate and stage 1 electric heat will be energized and the fan will operate at its electric heat setting. For

units equipped with 2 stages of electric heat, if room setpoint conditions are still not satised, the second

stage of electric heat will be energized and the fan will continue to operate at its electric heat setting. When

the room setpoint conditions are satised, electric

heat will be de-energized allowing the compressor

to remain on if necessary to maintain room setpoint conditions. The fan will operate according to its “fan only” setting when enabled, for continuous fan operation. If fan cycling is enabled, the fan will turn

off once room setpoint conditions are satised.

■ Primary Electric Heat mode – On an initial call for

heating, stage 1 electric heat will be energized and the fan will start at its electric heat setting. For units

equipped with 2 stages of electric heat, if room setpoint conditions are not satised, the second stage

of electric heat will be energized and the fan will continue to operate at its electric heat setting. When

the room setpoint conditions are satised, electric

heat will be de-energized and the fan will continue to operate at its “fan only” setting when enabled, for continuous fan operation. If fan cycling is enabled, the

fan will turn off after 30 seconds once room setpoint conditions are satised.

■ Emergency Electric Heat mode – A 24v control signal

from the thermostat will initiate a call for stage 1 or stage

2 electric heat. The compressor will not operate and the

fan will start at its electric heat setting.

■ Occupied Mode – The MicroTech III SmartSource unit

controller will manage occupied and unoccupied modes of operation. The occupancy mode can be established by a BACnet or LonWorks communication signal, from a

room sensor equipped with “Occupied/Unoccupied” mode

functions, or a thermostat equipped with an “Occupied/

Unoccupied” mode switch. When in the occupied

mode, the unit will be controlled to its occupied setpoint conditions. The occupancy state will be displayed on

sensors equipped with “Occupied/Unoccupied” mode

functions and annunciation capabilities.

■ Unoccupied Mode – When operating in the unoccupied

mode, the unit will be controlled to its unoccupied setpoint conditions and the fan will cycle according to a call for

cooling, dehumidication or heating. A simple “grounded” signal between terminals U and C on the MicroTech

III SmartSource unit controller will place the unit into the unoccupied mode for night setback operation. The occupancy state will be displayed on sensors equipped

with “Occupied/Unoccupied” mode functions and

annunciation capabilities.

■ Override Mode – A momentary (4 to 9 seconds) press of

the “Override” button on the thermostat or room sensor during the unoccupied mode will cause the unit to operate in the occupied mode for two hours, for after-hours

heating, cooling or dehumidication. “OVERRIDE” will

be displayed on sensors equipped with override button and annunciation capabilities.

OM 1149 / Page 9 of 40

■ “Energy Save” Bypass Mode – BACnet or LonWorks units can receive a signal from the Building Automation

System (BAS) to initiate the energy savings mode. This

mode is typically initiated by the BAS with smart grid technologies to save energy. The savings is driven by reducing peak electrical demand for the building. Once initiated, the MicroTech III SmartSource unit controller will reset its effective setpoint to minimize the stage

of compressor operation. “E-SAVE” will be displayed

on sensors equipped with bypass mode annunciation capabilities.

■ Motorized Water Valve or Pump Start – When there is a call for cooling, dehumidication or heating, the

MicroTech III SmartSource unit controller will energize

its IV/PR (H8) terminal to open the motorized water valve or start the loop pump 30 seconds prior to starting the compressor. The IV/ PR (H8) terminal may be “daisy

chained” between 200 units.

Control Inputs (HP, LP, SLTS, COF, U, E, O)

The control inputs are High Pressure (HP), Low Pressure (LP), Suction Line Temperature Sensor (SLTS), Condensate Overow (COF), Unoccupied (U), and Remote Shutdown (E). The control inputs are in normal states during occupied

mode. The state of each control in occupied mode during normal operation is as follows:

■ High Pressure (HP): Normally closed switch that opens

on a high refrigerant pressure condition. Control will generate a high pressure fault and disables the compressor output when the switch is open.

■ Low Pressure (LP): Normally closed switch that opens on

a low refrigerant pressure condition. Control will generate

a low pressure fault when the switch is open. Suction Line Temperature Sensor (SLTS): temperature sensor on the

suction line.

■ Condensate Overow (COF): senses condensate level

in condensate pan. Control will generate a fault when condensate level is too high.

■ Unoccupied (U): Grounding this terminal puts the control

into unoccupied mode.

■ Remote Shutdown (E): Grounding this terminal forces the

control to shutdown the unit.

Control Outputs {A and IV/PR (H8)}

The control outputs are Alarm Fault (A) and Isolation Valve / Pump Request {IV/PR (H8)}. The operation of the control

outputs during occupied mode is as follows:

■ The thermostat alarm output will be energized when there

are fault conditions presently active. Without any fault conditions active, the alarm output shall be de-energized.

■ Isolation Valve / Pump Request {IV/PR (H8)}: is

selectable to be energized when the compressor is

off (normally closed), or when the compressor is on (normally open), by moving the wire lead to the

appropriate terminal.

Figure 3: H8 Terminals on MicroTech III Board

■ Reversing Valve: 24V signal that is energized upon a call

for heat mode.

■ Compressor Relay: Line or low voltage output used to control compressor. (On/Off)

Fan Operation

The G terminal controls continuous fan operation. The fan runs continuously when the G terminal is energized. When the G terminal is de-energized, the fan cycles with the compressor.

Cooling Mode

The Y1 terminal controls the Cooling Mode of operation.

When the Y1 terminal is energized (24VAC), the following

occurs:

1. The fan energizes.

2. The IV/PR (H8) control output de-energizes or energizes depending on the H8 terminal wiring (refer to Table 1 on

page 4 & Figure 1 on page 6).

3. The compressor energizes after 30 seconds.

4. The reversing valve de-energizes 5 seconds after the

compressor turns on.

When the Y1 terminal is de-energized, the following occurs:

1. The compressor de-energizes.

2. The IV/PR (H8) control output energizes or de-energizes depending on the H8 terminal wiring (refer to Table 1 on

page 4 & Figure 1 on page 6).

3. The fan de-energizes, unless the G terminal is energized (24VAC).

Note: To prevent compressor cycling and all compressors

from starting up together after loss of power, the required minimum on/off time default is 180 seconds. This may cause the compressor time delay to be longer than indicated above.

Page 10 of 40 / OM 1149

Heating Mode

The W1 terminal controls the occupied Heating Mode of operation. When the W1 terminal is energized, the following occurs:

1. The fan energizes.

2. The IV/PR (H8) control output de-energizes or energizes depending on the H8 terminal wiring (refer to Table 1 on

page 4 & Figure 1 on page 6).

3. The compressor energizes after 30 seconds.

4. The reversing valve energizes 5 seconds after the

compressor turns on.

When the W1 terminal is de-energized, the following occurs:

1. The compressor de-energizes.

2. The IV/PR (H8) control output energizes or de-energizes depending on H8 terminal wiring (refer to Table 1 on page

4 & Figure 1 on page 6).

3. The fan de-energizes, unless the G terminal is energized.

Note: To prevent compressor cycling, the required minimum

on/off time default is 180 seconds. This may cause the compressor time delay to be longer than indicated above.

Unoccupied Operation – Stand Alone Thermostat Control

The board will be in unoccupied mode if the unoccupied

terminal (U) is grounded.

Yellow Green Red On On Off

Board LED Status – Unoccupied

Thermostat Inputs (G, Y1, Y2, W1, and W2)

The only thermostat inputs used during unoccupied operation

are Y2 and W2, which when energized will activate Cooling

Mode or Heating Mode respectively. Inputs G, Y1 and W1 have no effect during unoccupied mode.

Figure 4: Terminal "U" - Grounded for Unoccupied

Additional Fault Modes

Brownout

Yellow Green Red Off Flash Off

Brownout condition is provided to protect the water source heat pump’s motor electrical damage due to low voltage conditions.

The MicroTech III unit controller is designed to monitor the

24VAC power supply to the board. If the line voltage supplied to the water source heat pump drops, the 24VAC supply

to the control board will also drop. When the line voltage

supplied to the unit drops below approximately 80% of the

unit nameplate rated value, the controller goes into brownout condition. The controller remains in brownout condition until line voltage returns to approximately 90% of the unit nameplate value.

When in brownout condition, thermostat and control inputs have no affect upon unit operation. Remote shutdown and brownout conditions have the same level of priority. See "Pri-

ority Level of Faults and Modes" on page 14.

When the unit is in brownout condition the following occurs:

1. The compressor de-energizes.

2. The fan de-energizes.

3. Fault terminal (A) energizes (fault). A to R will be used to

indicate an alarm signal.

When the line voltage supplied to the unit returns to accept-

able levels (~90% of nameplate) the controller returns to the

current mode.

Remote Shutdown

Yellow Green Red Off Flash Off

When the E terminal is grounded, the MicroTech III unit

controller enters remote shutdown mode. Remote shutdown is provided so that when properly connected to a building

automation system, remote switch, etc., the E terminal can be

used to shut down the water source heat pump.

Figure 5: Terminal "E" - Grounded for Remote Shutdown

Board LED Status – Brownout

Board LED Status – Remote Shutdown

OM 1149 / Page 11 of 40

When in remote shutdown (E terminal grounded), thermostat

and control inputs have no affect upon unit operation. No faults or modes have higher priority than remote shutdown. Remote shutdown and brownout condition have the same level of priority. See "Priority Level of Faults and Modes" on page 14.

When the unit is in remote shutdown mode, the following occurs:

1. The compressor de-energizes (if enabled).

2. The fan de-energizes (if enabled).

3. Fault terminal (A) will remain de-energizes because

emergency shutdown is a "mode". A to C will be used to indicate normal operation.

When the E terminal is no longer grounded the unit will automatically return to normal operation.

Note: The remote shutdown input (E) will suspend unit

operation. Disconnect power when servicing the unit/ controller.

High / Low Pressure Faults (HP/LP)

Normally closed high and low refrigerant pressure switches help protect the water source heat pump from excessively high or low refrigerant pressures. The MicroTech III unit controller monitors these switches individually. If the compressor is running and the HP circuit is open, the controller enters

a pressure fault mode. If the LP circuit is open after a time delay (default of 30 seconds, adjustable if a communication module is present) the controller enters a low pressure fault

mode.

Yellow Green Red HP Off Off Flash LP Off Off Solid

See "Priority Level of Faults and Modes" on page 14..

When the unit is in high or low pressure fault modes the following occurs:

1. The compressor de-energizes.

2. The IV/PR(H8) output will change state. (On to Off / Off to On).

3. The fan de-energizes.

4. The fault terminal (A) energizes (fault). A to R will be

used to indicate an alarm signal.

High Pressure Reset

After the HP circuit is closed, the unit does not return to normal operation until the alarm is manually reset. The unit is locked out in this manner until the unit can be serviced.

The alarm is reset by a short interruption of unit power, by

holding down the tenant override button for more than 10 seconds, or via the Building Automation System (BAS).

Low Pressure Reset

The low pressure switch fault is subject to intelligent reset. If the pressure recovers, it resets two times within a 24-hour time period. If further faults are detected within the 24 hours,

the controller must be manually reset as described in the High Pressure Reset section above.

Board LED Status – High/Low Pressure Faults

Low Suction Temperature Fault Heating

1. The control will attempt to recover from a low suction temperature condition by defrosting water heat exchanger

(coaxial coil).

2. See the Defrost Process below for details.

Low Suction Temperature Fault Cooling

1. When the suction line temperature falls below 28° F

disable the compressor output only.

2. The fan will continue to run drawing warmer air over the

air heat exchanger.

3. When the suction line temperature increases by Low Temp Protect Diff (the default is 8° F) degrees.

4. The compressor is available for cooling if the Compressor

Minimum Off timer has expired.

5. Mark the occurrence of the fault.

Yellow Green Red Flash Off Off

Board LED Status – Low Suction Line Temperature Fault

Defrost Sequence of Operation:

1. Immediately turn off the compressor if operating in the

cooling or dehumidication modes.

2. The fan will remain on at the existing fan speed if the unit is cooling, dehumidifying or congured for electric heat

3. The reversing valve output is de-activated, placing the

reversing valve in the cooling mode and moving warm refrigerant to the coax coil.

4. Fan speed is not changed, however “Heat Stage #1” speed

is used if the fan is presently off.

5. If the compressor was on at the beginning of the defrost process, then start the 60 second xed defrost timer.

6. Wait for the defrost timer to expire.

7. If the alarm condition has cleared:

· Return to normal operation.

8. If the alarm condition remains active:

• Compressor High Capacity is turned off

• Compressor is immediately turned off, ignoring the

Compressor Minimum ON timer

• Compressor is disabled for heating and cooling

• Electric heating can be used if it is available

• Fan and pump remain available for operation

Heating Mode

When the suction line temperature falls below 28°F on standard equipment (6.5°F on Geothermal) the low temperature

fault generates the following:

■ The reversing valve de-energizes. The compressor and fan continue to operate in cooling mode for 60 seconds, which

results in a defrost mode. This defrosts any ice that may have accumulated in the water-to-refrigerant coil, because

of a lack of condenser water ow in heat mode.

■ In heat mode the low temperature fault is subject to

Intelligent Reset.

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