Unit installation

10 OMRCPMICRO
Installation and Maintenance
The MicroTech controller is factory tested and configured for the unit being controlled.
Sensors and transducers
Sensors and transducers are mounted and connected to the MicroTech ADI board with shielded cable.
Transducers are on Shrader fittings and sensors are in wells except the optional suction and liquid line sensors
(in the refrigerant sensor package). The suction and liquid line sensors are placed in a copper sleeve that is
brazed to the copper tubing. Insulation is placed around the assembly.
Sensors and transducers are connected to the MicroTech analog inputs with IDC connectors (Insulation
Displacement Connectors).
To change the transducers, just unscrew and replace. The transducers have removable cables. High pressure
transducers have a red dot on them and low pressure transducers have blue dots. Sensors do not have
separate cables.
Control wiring
Low voltage control wiring is installed, labeled and tested by the factory before shipment.
Remote 4-20 milliamp signals
Signals for leaving water reset and demand limiting can be provided by the customer and should be connected
to the terminals on the field wiring strip inside the control cabinet. See the Field Wiring section for more
details.
Interlock wiring
All interlock wiring to field devices (such as flow switches and pump starters) is provided by the installing
contractor. See Figure 5, unit wiring schematics, and field wiring diagrams at the end of this manual for details.
Unit set points and calibration
The control software is installed and tested by the factory before shipping. No periodic calibration of the
controller is necessary. All control and safety set points must be checked by the installing contractor and
adjusted as necessary before starting the unit. Controllers for McQuay chillers and Templifiers have default
set points (shown on Menus 13 through 22, in Table 8 on page 52) for:
Ø Control mode
Ø Leaving water temperature
Ø Head pressure settings
Ø Compressor staging
Ø Softloading
Ø Holiday dates
Ø Internal scheduling
Ø Alarm functions
The default set points are suitable for most installations.
On Menu 13, the default control mode is set for "Manual Unit Off". Adjust this setting before continuing with
unit operation. Check and set the control and safety settings for the application before staging the unit. For
more information on menu items, see the Menu Description section of this manual.
Modem kit
An optional modem kit allowing remote monitoring of the chiller from an off-site PC running the McQuay
Monitor software is available from McQuayService. The kit, complete with modem, mounting bracket, wiring