McQuay SEASONCON ALP-150C User Manual

59 pages

Questions and Answers:

K
Krystal LopezAug 19, 2025
Why McQuay Heat Pump compressor will not run?
- C
  Christina BlackSep 12, 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).
J
jtylerAug 21, 2025
What to do if my McQuay Heat Pump has low suction pressure?
- C
  chelseaadkinsAug 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).
S
scarterAug 23, 2025
How to fix high discharge pressure in McQuay Heat Pump?
- M
  Mark ParkerAug 23, 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).
D
daviskevinAug 27, 2025
Why my McQuay Heat Pump compressor loses oil?
- A
  amber37Aug 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).
S
stephen97Aug 30, 2025
How to reduce noise of vibrating McQuay Heat Pump compressor?
- T
  Troy PettyAug 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).
P
Paul JohnsonSep 1, 2025
What causes low discharge pressure in McQuay Heat Pump?
- S
  sarah69Sep 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).
M
mhernandezSep 3, 2025
What to do if McQuay Heat Pump has high suction pressure?
- B
  baldwintoddSep 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).
A
Anita MckinneySep 5, 2025
Why McQuay Heat Pump compressor thermal protector switch open?
- C
  Christine BergerSep 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).
R
Richard King IVSep 7, 2025
What causes McQuay Heat Pump compressor not to unload or load?
- A
  Andrea SalasSep 7, 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.
P
Patrick StantonSep 9, 2025
What to do if liquid line solenoid will not open in McQuay Heat Pump?
- S
  schneiderrichardSep 9, 2025
  Repair or replace the coil.

McQuay SEASONCON ALP-150C Specifications

General

Brand	McQuay
Model	SEASONCON ALP-150C
Category	Heat Pump
Language	English

Summary

REFRIGERANT PIPING

FIELD WIRING

STARTUP AND SHUTDOWN

PRE-STARTUP

Details essential checks to perform before initial unit start.

INITIAL STARTUP

Provides step-by-step procedures for first-time unit startup.

TYPICAL CONTROL AND SAFETIES WIRING DIAGRAMS

TYPICAL THERMOSTAT WIRING DIAGRAMS

SYSTEM MAINTENANCE

GENERAL

Covers routine service checks and operational observations.

SERVICE

Details procedures for filter-driers, solenoid valves, and thermostatic expansion valves.

APPENDIX

STANDARD CONTROLS

Provides an overview of the unit's built-in safety and operational controls.

HIGH PRESSURE CONTROL

Explains the operation and settings of the high-pressure safety switch.

LOW PRESSURE CONTROL

Details the function and settings of the low-pressure safety switch.

FANTROL HEAD PRESSURE CONTROL

Describes the system for modulating fan speed based on head pressure.

COMPRESSOR LOCKOUT

Explains the time delay feature to prevent rapid compressor cycling.

COMPRESSOR MOTOR PROTECTOR

PHASE/VOLTAGE MONITOR (OPTIONAL)

HOT GAS BYPASS (OPTIONAL)

ALP CONTROLS, SETTINGS, AND FUNCTIONS

HIGH PRESSURE CONTROL

Details function, symbol, setting, reset, location, and differential for HP control.

TROUBLESHOOTING CHART

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