McQuay SEASONCON ALP-055C User Manual

59 pages

Questions and Answers:

A
Alexis RobinsonAug 19, 2025
Why McQuay Heat Pump compressor will not run?
- K
  Kathy Campos DVMAug 19, 2025
  The compressor might not be running due to several reasons. The main switch could be open (close it), a fuse could be blown (replace the fuse or reset breakers after correcting the fault), or circuit breakers could be open (check electrical circuits and motor winding for shorts or grounds). Thermal overloads might have tripped (check the unit closely when it comes back online), the contactor or coil could be defective (repair or replace it), or the system might have been shut down by safety devices (determine the type and cause of shutdown and correct it before resetting the safety switch).
B
Bryan DavidsonAug 21, 2025
What to do if my McQuay Heat Pump has low suction pressure?
- C
  Chad LopezAug 21, 2025
  Low suction pressure may be due to several factors. There could be a lack of refrigerant (check for leaks, repair, and add charge), a dirty evaporator (clean it chemically), or a clogged liquid line filter-drier (replace it). Additionally, the suction line or compressor suction gas could be clogged (clean strainers), the expansion valve might be malfunctioning (check and reset for proper superheat), or the condensing temperature may be too low (check the means for regulating condensing temperature).
W
wmcfarlandAug 23, 2025
How to fix high discharge pressure in McQuay Heat Pump?
- A
  Ashley MorrisonAug 25, 2025
  High discharge pressure can occur due to several reasons: there may be noncondensables in the system (purge them), the system might be overcharged with refrigerant (remove the excess), the discharge shutoff valve could be partially closed (open the valve), or the fan might not be running (check the electrical circuit).
J
Jason TylerAug 28, 2025
Why my McQuay Heat Pump compressor loses oil?
- L
  Lisa HooverAug 28, 2025
  The compressor may lose oil due to a lack of refrigerant (check for leaks and repair; add refrigerant), excessive compression ring blow-by (replace the compressor), suction superheat being too high (adjust superheat), or a burned-out crankcase heater (replace the crankcase heater). Other causes may include insufficient oil in the system (add oil until the sight glass is 1/3 full), suction risers that are too large (check line sizing at design conditions and change if incorrect), or insufficient traps in suction risers (install suction P-traps at each 20-foot vertical rise).
J
johnhuffAug 30, 2025
How to reduce noise of vibrating McQuay Heat Pump compressor?
- P
  Patrick MooreAug 30, 2025
  A noisy or vibrating compressor may be caused by flooding of refrigerant into the crankcase (check the setting of the expansion valve) or improper piping support on the suction or liquid line (relocate, add, or remove hangers).
A
Adam BriggsSep 1, 2025
What causes low discharge pressure in McQuay Heat Pump?
- A
  Alan WiseSep 1, 2025
  Low discharge pressure can be attributed to a dirty condenser coil (clean the coil) or a FANTROL out of adjustment (adjust FANTROL settings).
T
Thomas LandrySep 3, 2025
What to do if McQuay Heat Pump has high suction pressure?
- S
  Sean MaySep 3, 2025
  High suction pressure can be caused by an excessive load (reduce the load or add additional equipment) or an expansion valve overfeeding (check the remote bulb and regulate superheat).
G
George VanceSep 5, 2025
Why McQuay Heat Pump compressor thermal protector switch open?
- B
  Brandon CameronSep 5, 2025
  The compressor thermal protector switch might be open due to operating beyond design conditions (add facilities so conditions are within allowable limits), a discharge valve being partially shut (open the valve), or a blown valve plate gasket (replace the gasket).
A
Abigail KleinSep 7, 2025
What causes McQuay Heat Pump compressor not to unload or load?
- J
  jedwardsSep 8, 2025
  The compressor's failure to unload or load may be due to a defective capacity control (replace it), a defective unloader mechanism (replace it), or a faulty thermostat stage or broken capillary tube (replace it). Also, ensure that the thermostat setting is appropriate for the application by resetting it.
H
Henry DawsonSep 10, 2025
What to do if liquid line solenoid will not open in McQuay Heat Pump?
- S
  stephaniefarrellSep 10, 2025
  Repair or replace the coil.

McQuay SEASONCON ALP-055C Specifications

General

Model	ALP-055C
Category	Heat Pump
Cooling Capacity	5.5 kW
Heating Capacity	6.0 kW
Refrigerant	R410A
Sound Pressure Level (Indoor)	42 dB(A)
Sound Pressure Level (Outdoor)	52 dB(A)
Operating Temperature Range (Heating)	-7-24°C
Power Supply	220-240V/50Hz

Summary

Introduction and Installation

Unit Handling Procedures

Installation and Service Access

Refrigerant Piping Guidelines

General Refrigerant Piping Recommendations

Suction and Liquid Line Sizing

Details recommended sizing for suction and liquid lines based on pressure drop.

System Charging and Components

Refrigerant Charging Procedure

Details the step-by-step process for charging the unit with refrigerant.

Physical and Dimensional Data

Major Component Designations

Field Wiring and Diagrams

General Field Wiring Requirements

Outlines wiring compliance, materials, and specifications for unit installation.

Typical Power Wiring Diagrams

Typical Control and Safeties Wiring Diagrams

Typical Thermostat Wiring Diagrams

Electrical Data and Schematics Reference

Power Schematics Reference Table

Decision table to help select the correct power schematic drawing based on unit configuration.

Control and Safety Schematics Reference

Decision table to select the correct control and safety schematic drawing.

Thermostat Control Schematic Reference

Decision table to select the correct thermostat control schematic drawing.

Unit Operations and Maintenance

Flow Switch for Chilled Water Applications

Startup and Shutdown Procedures

Detailed steps for pre-startup, initial startup, temporary, and extended shutdowns.

System Maintenance Guidelines

Service and Component Procedures

Filter-Drier Replacement

Thermostatic Expansion Valve Adjustment

Warranty and Appendix Controls

Oil Pressure Safety Control

Description, function, and testing procedure for the oil pressure safety control.

High Pressure Control Operation

Description, function, and testing procedure for the high pressure control.

Low Pressure Control Operation

Description, function, and testing procedure for the low pressure control.

Fantrol Head Pressure Control

Compressor Lockout and Motor Protector

Speedtrol Head Pressure Control

Compressor Unloaders and Low Ambient Start

High Ambient and Part Winding Start Controls

Phase/Voltage Monitor and Hot Gas Bypass

ALP Controls, Settings, and Functions

Pressure Controls and Thermostats

Details pressure controls (HP, LP, Oil, Fantrol) and thermostats (Master, Satellite).

Motor Protection, Timing, and Switches

Solenoid Valves and Speed Controls

Low Ambient Start and Sequencing

Troubleshooting Compressor Issues

Compressor Not Running or Noisy

Lists causes and corrective steps for compressors that won't run, are noisy, or vibrate.

Discharge and Suction Pressure Problems

Troubleshooting high/low discharge and suction pressures, and noncondensables.

Loading/Unloading and Oil Pressure Issues

Addresses compressor loading/unloading problems and oil pressure loss.

Motor Overload and Thermal Protector

Causes and corrective steps for motor overloads, blown fuses, and thermal protector trips.

Related product manuals

McQuay SEASONCON ALP-045C

McQuay SEASONCON ALP-037A

McQuay SEASONCON ALP-070C

McQuay SEASONCON ALP-080C

McQuay SEASONCON ALP-090C

McQuay SEASONCON ALP-100C

McQuay SEASONCON ALP-120C

McQuay SEASONCON ALP-150C

McQuay SEASONCON ALP-170C

McQuay MHC Standard Range

McQuay ACZ 016A

McQuay WMF series