McQuay SEASONCON ALP-170C User Manual

59 pages

Questions and Answers:

E
Erin LarsonAug 19, 2025
Why McQuay Heat Pump compressor will not run?
- L
  Leonard BrownAug 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).
T
Tara ColeAug 21, 2025
What to do if my McQuay Heat Pump has low suction pressure?
- E
  Elizabeth SimonAug 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).
P
patrick60Aug 23, 2025
How to fix high discharge pressure in McQuay Heat Pump?
- J
  Jessica HowardAug 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).
B
brownjuliaAug 28, 2025
Why my McQuay Heat Pump compressor loses oil?
- D
  Diana JohnsonAug 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).
G
gregoryjessicaAug 30, 2025
How to reduce noise of vibrating McQuay Heat Pump compressor?
- S
  Sarah KiddAug 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
Alex EdwardsSep 1, 2025
What causes low discharge pressure in McQuay Heat Pump?
- S
  sjohnsonSep 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
Timothy NewtonSep 3, 2025
What to do if McQuay Heat Pump has high suction pressure?
- J
  Jennifer SmithSep 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).
S
Stephen DavisSep 5, 2025
Why McQuay Heat Pump compressor thermal protector switch open?
- C
  Crystal RodriguezSep 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).
C
Cindy ConwaySep 7, 2025
What causes McQuay Heat Pump compressor not to unload or load?
- A
  Alexander AdamsSep 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.
J
Jonathan MasonSep 10, 2025
What to do if liquid line solenoid will not open in McQuay Heat Pump?
- A
  Alan DaviesSep 10, 2025
  Repair or replace the coil.

McQuay SEASONCON ALP-170C Specifications

General

Brand	McQuay
Model	SEASONCON ALP-170C
Category	Heat Pump
Language	English

Summary

ELECTRICAL LEGEND

COMPONENT DESIGNATIONS

Provides a comprehensive list of electrical component designations and their functions.

NORMAL SEQUENCE OF OPERATION

STARTUP

Describes the typical startup sequence for the ALP condensing unit.

PUMPDOWN

Explains the pumpdown cycle and its role in refrigerant management.

TYPICAL POWER WIRING DIAGRAMS

SINGLE POINT, WITHOUT SPEEDTROL

Power wiring diagrams for units with single point connection, no Speedtrol.

MULTIPLE POINT WITHOUT SPEEDTROL

Power wiring diagrams for units with multiple point connection, no Speedtrol.

SINGLE POINT, WITH SPEEDTROL

Power wiring diagrams for units with single point connection and Speedtrol.

TYPICAL CONTROL AND SAFETIES WIRING DIAGRAMS

ALP-045C, 055C, 070

ALP-080C, 090C, 100C, 110C

ALP-120C, 135C, 150C, 170C, 185C, 205C, 230C

STARTUP AND SHUTDOWN

PRE-STARTUP

Essential checks and procedures before initial unit startup.

INITIAL STARTUP

Step-by-step guide for starting the unit for the first time.

TEMPORARY SHUTDOWN

EXTENDED SHUTDOWN

SYSTEM MAINTENANCE

COMPRESSOR OIL LEVEL

Guidance on checking and maintaining the compressor oil level.

APPENDIX

STANDARD CONTROLS

Overview of essential safety and operational controls included in the unit.

HIGH PRESSURE CONTROL

Details the function, setting, and testing of the high pressure safety control.

LOW PRESSURE CONTROL

Explains the low pressure control's role in pumpdown and system operation.

FANTROL HEAD PRESSURE CONTROL

COMPRESSOR LOCKOUT

COMPRESSOR MOTOR PROTECTOR

OPTIONAL CONTROLS

SPEEDTROL HEAD PRESSURE CONTROL

LOW AMBIENT START

PHASE/VOLTAGE MONITOR

HOT GAS BYPASS

ALP CONTROLS, SETTINGS, AND FUNCTIONS

CONTROL CATEGORIES SUMMARY

SPECIALIZED CONTROL FUNCTIONS SUMMARY

TROUBLESHOOTING CHART

COMPRESSOR WILL NOT RUN

Lists possible causes and corrective steps when the compressor fails to start.

COMPRESSOR NOISY OR VIBRATING

Identifies causes and solutions for compressor noise and vibration issues.

HIGH DISCHARGE PRESSURE

Lists possible causes and corrective steps for high discharge pressure.

LOW DISCHARGE PRESSURE

Lists possible causes and corrective steps for low discharge pressure.

HIGH SUCTION PRESSURE

Lists possible causes and corrective steps for high suction pressure.

LOW SUCTION PRESSURE

Lists possible causes and corrective steps for low suction pressure.

COMPRESSOR WILL NOT UNLOAD OR LOAD

Lists possible causes and corrective steps for compressor loading issues.

COMPRESSOR LOADING/UNLOADING INTERVALS TOO SHORT

Lists possible causes and corrective steps for short compressor cycling intervals.

LOSS OF OIL PRESSURE OR NUISANCE OIL PRESSURE CONTROL TRIPS

Lists possible causes and corrective steps for oil pressure related trips.

COMPRESSOR LOSES OIL

Lists possible causes and corrective steps for compressor oil loss.

MOTOR OVERLOAD RELAYS OPEN OR BLOWN FUSES

Lists possible causes and corrective steps for motor overload or blown fuses.

COMPRESSOR THERMAL PROTECTOR SWITCH OPEN

Lists possible causes and corrective steps for thermal protector trips.

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