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.
Step-by-step guide for installing the unit, covering initial setup and connection points.
Instructions for changing the unit's air discharge direction from straight to end.
Guidelines for connecting ductwork, including transition pieces and acoustic insulation.
Recommendations for introducing outside air into the return air system for ventilation.
Overview of electrical requirements, wiring compliance, and component connections.
Specific instructions for setting up the unit for 230-volt power supply.
Details on fan motor wiring, speed selection, and connections.
Specifies the acceptable ambient and air temperature ranges for unit operation.
Defines the acceptable entering water temperature ranges for cooling and heating modes.
Details on specific conditions and settings recommended for initial unit start-up.
Lists the minimum and maximum acceptable operating voltages for the unit.
Illustrates the internal wiring for units equipped with the Mark IV/AC control system.
Shows the wiring schematic for units using the MicroTech 2000 controller.
Presents the wiring schematic for units controlled by the BACnet WSHP controller.
Explains the features and operation of the Mark IV/AC control board.
Describes the functionality and operation of the MicroTech 2000 control system.
Details the features and operational modes of the BACnet WSHP control system.
Wiring diagrams and instructions for connecting 7-day programmable thermostats.
Wiring diagrams and instructions for connecting non-programmable thermostats.
Guidance on installing and wiring an optional remote sensor for temperature monitoring.
Information on using the auxiliary relay for fault signals or unit operation indicators.
Details on controlling up to three units from a single thermostat using a control board.
Details on controlling up to two units from a single thermostat using a control board.
Instructions for installing and wiring a motorized valve and associated relay.
Information on the Boilerless System Kit for controlling remote duct heaters.
Details on installing and wiring the pump restart relay kit for system pump control.
How to configure output signals for scheduled operation on MicroTech 2000 units.
How to use the auxiliary heat output for remote electric heaters.
How to use outputs to control a remote fresh air damper.
How to use outputs to control a motorized water valve.
Explanation of the functions of each pin on the 14-position terminal strip.
Description of the LED indicators and their meaning for unit status and faults.
General information and tips for using the Mark IV/AC control system.
A visual guide to diagnosing common WSHP problems and their solutions.
Details about R-410A refrigerant, its properties, and handling precautions.
A table correlating symptoms with refrigerant circuit conditions.
Diagram and explanation of the refrigerant flow during cooling operation.
Diagram and explanation of the refrigerant flow during heating operation.
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