McQuay Enfinity series

Questions and Answers

A
amandafrankAug 3, 2025
What to do if my McQuay Heat Pump compressor attempts to start but does not?
- J
  Jessica KaiserAug 3, 2025
  If your McQuay Heat Pump compressor attempts to start but fails, first examine the compressor wiring for any defects or loose connections. Additionally, use an ohmmeter to check the compressor's internal windings for any defects.
C
Cynthia PearsonAug 10, 2025
What to do if my McQuay Heat Pump has a hi pressure lockout?
- K
  Katrina HughesAug 10, 2025
  If your McQuay Heat Pump is experiencing a high-pressure lockout, there are several things to check. If in cool mode, check the water flow. If in heating mode, check the air flow. Also, verify the reversing valve for proper valve position.
S
Stephen TerryAug 18, 2025
Why are neither the fan nor the compressor running on my McQuay Heat Pump?
- R
  Robert HobbsAug 18, 2025
  If neither the fan nor the compressor of your McQuay Heat Pump are running, begin by inspecting the wiring for any loose or broken connections. Also, check the relays and contacts, and inspect for a bad capacitor and wiring connection.
M
mitchellbakerAug 26, 2025
How to fix low voltage on my McQuay Heat Pump?
- T
  Tiffany ParkerAug 26, 2025
  If your McQuay Heat Pump is showing low voltage, this could be due to a blown fuse or an open circuit breaker. Replace the fuse or reset the breaker. You should also replace or retighten wires for correct wiring or if there is a bad thermostat.

Summary

Transportation and Storage Guidelines

General Installation Procedures

Unit Location and Clearances

Details optimal placement for unit access, maintenance, and proper operation.

Electrical and Piping Information

Piping Installation Requirements

Covers system configuration, materials, valve requirements, and system flushing.

Cleaning and Flushing the Water System

Unit Start-up Procedures

Start-up Troubleshooting Checklist

Lists common issues and checks if the unit fails to operate during initial start-up.

Operating Limits and Environmental Conditions

Unit Operation Modes

Mark IV;AC Control Unit Operation

Details features like random start, time delay, lockout circuits, and LED fault outputs.

MicroTech 2000 WSHP Unit Controller

Thermostat Connection Diagrams

Mark IV;AC Sequence of Operation

Troubleshooting Water Source Heat Pump

R410 A Refrigerant Information

Troubleshooting Refrigeration Circuit

The document provides installation and maintenance data for McQuay Enfinity Vertical Water Source Heat Pumps, covering unit sizes 007-012 (R-22 refrigerant) and 019-060 (R-410A refrigerant). The manual, identified as IM 778-2, was published in June 2006.

Function Description:

The McQuay Enfinity Vertical Water Source Heat Pumps are designed for indoor installation, providing heating and cooling for various applications. These units are available with different control systems, including Mark IV/AC, MicroTech™ 2000, and BACnet® controllers, allowing for integration into building automation systems. They operate by transferring heat to or from a water loop, making them suitable for water source heat pump systems.

Important Technical Specifications:

Refrigerant Types: R-22 (for unit sizes 007-012) and R-410A (for unit sizes 019-060).
Nominal Capacities: Ranging from 7,000 to 60,000 BTU/hr, indicated by model numbers (007, 009, 012, 019, 024, 030, 036, 042, 048, 060).
Voltage Options: Multiple voltage configurations are available, including 115/60/1, 208-230/60/1, 208-230/60/3, 277-265/60/1, 460/60/3, 575/60/3, 230/50/1, and 380/50/3.
Operating Voltages (Ranges):
- 115/60/1: 104V min.; 127V max.
- 208-230/60/1: 197V min.; 253V max.
- 265/60/1: 238V min.; 292V max.
- 230/50/1: 197V min.; 253V max.
- 460/60/3: 414V min.; 506V max.
- 380/50/3: 342V min.; 418V max.
- 575/60/3: 515V min.; 632V max.
Air Limits (Standard Range Units):
- Min. Ambient Air: 50°F (10°C)
- Normal Ambient Air: 80°F (27°C) Cooling, 70°F (21°C) Heating
- Max. Ambient Air: 100°F (38°C) Cooling, 85°F (29°C) Heating
- Min. Ent. Air: 50°F (10°C)
- Normal Ent. Air (dw/wb): 80/67°F (27/19°C) Cooling, 70°F (21°C) Heating
- Max. Ent. Air (db/wb): 100/83°F (38/28°C) Cooling, 80°F (27°C) Heating
Air Limits (Geothermal Range Units):
- Min. Ambient Air: 40°F (5°C)
- Normal Ambient Air: 80°F (27°C) Cooling, 70°F (21°C) Heating
- Max. Ambient Air: 100°F (38°C) Cooling, 85°F (29°C) Heating
- Min. Ent. Air: 50°F (10°C) Cooling, 40°F (5°C) Heating
- Normal Ent. Air (dw/wb): 80/67°F (27/19°C) Cooling, 70°F (21°C) Heating
- Max. Ent. Air (db/wb): 100/83°F (38/28°C) Cooling, 80°F (27°C) Heating
Water Limits (Standard Range Units):
- Min. Ent. Water: 55°F (13°C)
- Normal Ent. Water: 85°F (29°C) Cooling, 70°F (21°C) Heating
- Max. Ent. Water: 110°F (43°C) Cooling, 90°F (32°C) Heating
Water Limits (Geothermal Range Units):
- Min. Ent. Water: 30°F (-1°C) Cooling, 20°F (-6°C) Heating
- Normal Ent. Water: 77°F (25°C) Cooling, 40°F (5°C) Heating
- Max. Ent. Water: 110°F (43°C) Cooling, 90°F (32°C) Heating
R-410A Refrigerant Specifications:
- Superheat: 8 to 14 degrees
- Head Pressure: 335-355 PSIG
- Water Delta T: 10° to 12°
Fan Motors: Multi-speed, PSC type with integral mounting brackets and thermal overload protection.
Piping: Units should be connected to supply and return piping in a two-pipe reverse return configuration. Flexible hoses are recommended for sound attenuation. Condensate piping can be steel, copper, or PVC.

Usage Features:

Installation Flexibility: Units can be installed "free standing" in an equipment room or in closets. Ducted or non-ducted return air arrangements are supported. Minimum clearance requirements for return air duct collars are specified based on unit size.
Filter Access: Each unit is shipped with a filter bracket for side filter removal.
Control Systems:
- Mark IV/AC Control Units: Feature random start, compressor time delay, night setback, load shed, condensate overflow protection, defrost cycle, brownout, and LED/fault outputs. Compatible with 24V mercury bulb or microelectronic wall thermostats. Includes a lockout circuit for safety switches (high/low pressure, low temperature, condensate sensor). Remote reset and fault retry features are available.
- MicroTech™ 2000 WSHP Unit Controller: Microprocessor-based, communicates over LonWorks networks. Monitors and controls unit operation, water and air temperatures, and communicates fault conditions. Includes return air, discharge air, and leaving water temperature sensors. Supports tenant setpoint adjustment and override. Features include occupied/unoccupied modes, after-hours override, short cycle protection, random start, reversing valve delay, and brownout protection. Status LED indicates operating mode and alarm conditions.
- BACnet® WSHP Unit Controller: Factory-mounted and tested, communicates over BACnet MS/TP networks to Alerton BACtalk building automation systems. Monitors equipment status, temperatures, and fault conditions. Supports remote setpoint changes. Features include start-up checks, customizable fan operation, cooling/heating modes with proportional-integral control, short cycle protection, random start, occupied/unoccupied modes, after-hours override, reversing valve delay, load shed, and brownout protection.
Optional Accessories:
- Auxiliary Relay (P/N 106059701): Interfaces external equipment, provides fault signals, unit operation signals, or remote control.
- Multiple Unit Control Boards (P/N 056794201 for up to 3 units, P/N 106059801 for up to 2 units): Allows control of multiple units from a single thermostat.
- Motorized Valve & Relay (P/N 060977401/060977301): Opens on a call for compressor operation.
- Boilerless System Kit (BSK) (P/N 062522204): Controls a remote duct heater, manually adjusts water temperature setpoint, and forces electric heat.
- Pump Restart Relay Kit (P/N 061419001): Alerts the loop water controller that water flow is required, starting the system pump.
- Field Installed Options on MicroTech 2000 Units: Provides up to 4 configurable outputs for scheduled output, auxiliary heat (skin heat), fresh air damper, or motorized water valve control.

Maintenance Features:

Filter Changes: Required at regular intervals, with initial checks at 60-day intervals. Filters should be changed if light cannot be seen through them.
Condensate Drain Pan: Should be checked, cleaned, and flushed annually.
Performance Measurement: Recording volts, amps, and water temperature differences (heating and cooling) helps indicate general equipment condition.
Troubleshooting Guides: The manual includes detailed troubleshooting flowcharts for general unit operation (fan/compressor issues) and refrigeration circuit problems (charge, air/water flow, TXV restrictions).
R-410A Handling: Emphasizes that R-410A must be charged as a liquid and requires specific recycle/recovery equipment designed for its higher pressure.
Motor Lubrication: Fan motors are permanently lubricated and do not require oiling during the first year of operation.
System Cleaning: Prior to first operation, the water circulating system must be cleaned and flushed of all construction dirt and debris. Trisodium phosphate was previously recommended but is now discouraged due to environmental concerns; flushing with warm 80°F (27°C) water for longer periods is recommended.
Water Treatment: After flushing, the system should be refilled with clean, slightly alkaline water (pH 7.5-8.5). Commercial grade antifreeze designed for HVAC systems can be added if needed. SystemSaver™ from McQuay is recommended to continuously remove solids.