To Next PageTo Next PageWhat to do if my McQuay Heat Pump compressor runs but does not cool?
If the compressor runs but the McQuay Heat Pump does not cool, inspect the compressor wiring for defects or loose connections. Also, verify proper airflow and check the blower assembly for dirt or a faulty fan motor. It's also advisable to check for a low refrigerant charge and inspect the compressor for defects.
What to do if neither the fan nor compressor runs on my McQuay Heat Pump?
If neither the fan nor the compressor runs on your McQuay Heat Pump, check the wiring for any looseness or breakage. Also, inspect the relays and contacts, and look for a bad capacitor and wiring connection.
Details the acceptable ranges for air and water temperatures during operation.
Illustrates the typical wiring for Mark IV/AC control units.
Shows the typical wiring for MicroTech 2000 WSHP unit controllers.
Displays the typical wiring for BACnet® WSHP unit controllers.
Details the features and operation of Mark IV/AC control systems.
Explains the functionality and operation of the MicroTech 2000 controller.
Describes the operation and features of the BACnet® WSHP unit controller.
A flowchart and guide for diagnosing common WSHP operational issues.
The McQuay Enfinity™ (R-410A) and Standard (R-22) Horizontal Water Source Heat Pumps (Models CRH, CRW Unit Sizes 007 – 070 / R-22 Refrigerant and Models CCH, CCW Unit Sizes 007 – 060 / R-410A Refrigerant) are designed for indoor installation and provide heating and cooling for commercial applications. This document outlines the installation, operation, and maintenance procedures for these units.
These units are water source heat pumps designed to provide efficient heating and cooling. They operate by transferring heat to or from a water loop, utilizing a refrigeration cycle. The units are available in two refrigerant types: R-22 for CRH/CRW models and R-410A for CCH/CCW models. The R-410A models offer higher operating pressure and refrigeration capacity compared to R-22. The units are designed to be suspended from the ceiling, with options for straight or end discharge airflow.
The heat pumps can be equipped with either a Mark IV/AC control unit or a MicroTech 2000 Water Source Heat Pump Unit Controller.
Mark IV/AC Control Units: These are microprocessor-based systems with built-in features such as random start, compressor time delay, night setback, load shed, shutdown, condensate overflow protection, defrost cycle, brownout, and LED/fault outputs for diagnostics. They are designed for operation with 24-volt mercury bulb or microelectronic wall thermostats. The control board manages fan, compressor, and reversing valve operation based on thermostat signals. It includes a lockout circuit to stop compressor operation if safety switches (high pressure, low pressure, low temperature) open or if the condensate sensor detects a filled drain pan. The Mark IV/AC system also supports remote reset of lockouts and a fault retry feature to minimize nuisance trips. Load shed and shutdown operations can be initiated via "grounded" signals to specific terminals. Pump restart functionality is provided, passing a voltage signal to a pump restart relay board when the compressor is on, allowing for loop circulation pump control.
MicroTech 2000 WSHP Unit Controller: This is a microprocessor-based controller designed to communicate over a LONWORKS® (LonTalk® or LonMark® 3.3) communications network, integrating with centralized building automation systems. It monitors and controls unit operation, water and air temperatures, and communicates fault conditions. Features include unit-mounted return air, discharge air, and leaving water temperature sensors, with options for wall-mounted room sensors, tenant setpoint adjustment, and override buttons. The controller provides an on-board status LED for diagnostics, indicating operating mode (Occupied, Occupied Load Shed, Unoccupied, Tenant Override, Override Load Shed) and alarm conditions (flashing).
BACnet® WSHP Unit Controller: This is a specialized Alerton BACnet unit controller that communicates over a BACnet MS/TP communications network to an Alerton BACtalk building automation system (BAS). Each controller has a unique MAC address set via DIP switches. It controls the compressor, fan, and reversing valve to maintain space temperature within setpoints. Operational data, commands, equipment status, water and air temperatures, and fault conditions are available on the BACtalk network. Features include start-up checks, customizable fan operation (continuous or cycling), proportional-integral control for cooling and heating run-time, short cycle protection (180-second start delay, 2-minute on, 5-minute off times), random start, occupied/unoccupied modes with configurable setpoints, after-hours override (half-hour increments up to 9.5 hours), reversing valve delay (60 seconds after heating, 10 seconds before compressor start), load shed, and brownout protection (suspends operation if voltage drops below 82% for 10 seconds, resets above 90%).
General| Refrigerant | R-410A |
|---|---|
| Compressor Type | Scroll |
| Series | CCH |
| Type | Heat Pump |
| Voltage Options | 208/230V |
| Unit Weight | Varies with model |
