2
McQuay IM 660-3
General Information
The MicroTech 2000™ WSHP unit controller provides control
of McQuay and AAF water source heat pumps. The controller
enables the mode of operation, monitors the water and air
temperatures, and indicates fault conditions. Each unit
controller is factory programmed, wired, and tested for
effective operation of your McQuay WHSP.
The MicroTech 2000 WSHP controller uses L
ON
W
ORKS
®
technology. One of the following two versions of the
application software is loaded into the controller at the factory.
L
ON
M
ARK
®
3.3 certified application code
is the current
standard application code for MicroTech 2000 units. Use
L
ON
M
ARK
application code in new applications including:
•
Units that operate stand alone.
•
Units that are integrated into a L
ON
W
ORKS
communication
network for communicating with a building automation
system (BAS) of your choice.
For network integration information, refer to the Protocol
Information document ED 15054. Unit controllers with
L
ON
M
ARK
application code have a software identification of
WHPE2E or higher.
LonTalk
®
application code
was designed prior to
certification. Use this application software only in existing
systems where an existing MicroTech Communications
Gateway (MCG) or MicroTech Communications Gateway for
Open Protocol (MCGOP) panel is installed. Use LonTalk
application code in existing systems where:
•
MicroTech 2000 WSHPs connect to a McQuay MicroTech
monitor through a MicroTech Communication Gateway
(MCG panel).
•
MicroTech 2000 WSHPs connect to a third party BAS
system through a MicroTech Communications Gateway for
Open Protocol (MCGOP) panel.
If you choose to upgrade your heat pumps, the other
application code can be installed in the field.
Component Data
Microprocessor
The MicroTech 2000 WSHP unit controller is a preprogrammed
microprocessor containing the software required to monitor and
control the unit. The controller supports a minimum of six
analog inputs, four digital inputs and five digital outputs
(including the LED). All electrical connections to the board are
provided by three mass termination style headers. Two of the
headers are designated strictly for factory wiring, the other for a
field wiring harness that terminates to a screw-type terminal
strip on the unit’s exterior.
The controller uses set points and fixed preprogrammed
parameters to maintain unit control (many of the set points and
preprogrammed parameters can be adjusted with a PC over the
network).
Yellow Status LED
A yellow, on-board status LED aids in diagnostics by indicating
the water source heat pump operating mode and alarm
conditions. The yellow LED indicates the unit operating mode
as shown in Table 2. For more information on alarms, refer to
the “Alarm monitoring and control” section on page 10.
A remote status LED is provided with all optional
wall-mounted temperature sensor packages. It has the same
function as the on-board status LED. If used, the remote LED
connects to the MicroTech WSHP controller at connection #1
on Terminal Board #1.
Service Pin
A service pin (button) is provided that can be used to cause the
Neuron
®
chip to broadcast a message over the L
ON
W
ORKS
network containing its unique 48-bit Neuron ID. This ID is
useful during network commissioning. For another method of
forcing the controller to broadcast its Neuron ID, see “Tenant
override” on page 5.
Red Service LED
A red on-board service LED provides diagnostics by
indicating the Neuron chip status. The red LED indicates the
Neuron chip status as shown in Table 3 below.
Temperature Sensing
The MicroTech 2000 WSHP unit controller uses negative
temperature coefficient (NTC) thermistors for temperature
sensing. A thermistor chart, which provides voltage-to-
temperature and resistance-to-temperature conversion data, is
included in Table 9 on page 12. The discharge air temperature
sensor is located at the inlet to the fan. The leaving water
temperature sensor is located in the leaving water line.
Table 2: Status LED indication
Status LED status
Mode
On continually
Occupied, Occupied Load Shed
On 0.5 sec, Off 5.5 sec
Unoccupied
On 5.5 sec, Off 0.5 sec
Tenant Override, Override Load Shed
On 0.1 sec, Off 0.1 sec
Alarm Condition (Condensate Overflow,
Brownout, Compressor Fault)
Table 3: Service LED indication
Service LED status
Mode
Off continually
(Normal) The Neuron has an application
and is configured.
On continually
The Neuron does not have an application
or is damaged. (Downloading an
application may correct this.)
Blink slowly
The Neuron has an application but is
unconfigured.