Compressor Evaluation Form 1ph/3ph – Carrier Enterprise Technical Services & Support

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Contractor / Technician Information

Complete this form while troubleshooting a failed compressor in the field.

Region *

Select the region where the job is located so this troubleshooting request routes to the correct Technical Service & Support team.

Dealer / Company Name *

Technician Name *

First

Last

Technician Mobile Phone *

Technician Email *

Are you currently on the job site? *

Note: This troubleshooting form is designed for live field readings. If you are not on the job site, provide the reason below and include any available diagnostic information.

If you are not currently on the job site, briefly explain why you are submitting without live readings. *

This form is intended for field troubleshooting. If you are not on site, explain what information is unavailable or why the form is being submitted now.

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Equipment Information

Outdoor Unit Model Number *

Installation Date *

Compressor Power Type *

Residential 1PH
Commercial 3PH

Outdoor Unit Serial Number *

Failure Date *

Primary compressor symptom / concern *

Will not start
Grounded winding
Shorted winding
Open winding
Tripped the breaker / fuse
Won’t pump
Low capacity
Noisy operation

Was all factory wiring confirmed to match the unit wiring diagram? *

If the unit has a capacitor, was the run capacitor tested? *

Was a hard start kit installed to try to start the compressor? *

Measured run capacitor capacitance (µF) *

Line voltage at the disconnect (VAC) *

Voltage on the load side of the contactor (VAC) *

Measure with the contactor engaged/calling for operation.

COMMON winding – compressor starting amps(LRA) *

COMMON winding – compressor running amps(RLA) *

RUN winding – compressor starting amps(LRA) *

RUN winding – compressor running amps(RLA) *

START winding – compressor starting amps(LRA) *

START winding – compressor running amps(RLA) *

L1 to L2 – Voltage Reading(VAC) *

L1 to ground – Voltage reading(VAC) *

L1 to L3 – Voltage Reading(VAC) *

L2 to ground – Voltage Reading(VAC) *

L2 to L3 – Voltage Reading(VAC) *

L3 to ground – Voltage Reading(VAC) *

L1 winding – compressor starting amps(LRA) *

L1 winding – compressor running amps(RLA) *

L2 winding – compressor starting amps(LRA) *

L2 winding – compressor running amps(RLA) *

L3 winding – compressor starting amps(LRA) *

L3 winding – compressor running amps(RLA) *

Important safety note

Before making the following electrical checks, disconnect electrical power to the outdoor unit and remove wiring from the compressor terminal connections.

C to R – Compressor winding resistance (Ω) *

C to ground – Resistance (Ω) *

C to S – Compressor winding resistance (Ω) *

R to ground – Resistance (Ω) *

R to S – Compressor winding resistance (Ω) *

S to ground – Resistance (Ω) *

L1 – L2 Compressor winding resistance (Ω) *

L1 to ground – Resistance (Ω) *

L1 – L3 Compressor winding resistance (Ω) *

L2 to ground – Resistance (Ω) *

L2 – L3 Compressor winding resistance (Ω) *

L3 to ground – Resistance (Ω) *

Was compressor winding resistance checked at the fusite/compressor terminals? *

Fusite/terminal test not completed

We would hate to see you do all of this work just because of a bad wire or wiring harness. Please go verify at the fusite/compressor terminals.

Required troubleshooting photos *

Drag & Drop Files, Choose Files to Upload You can upload up to 2 files.

Upload clear photos of the outdoor unit data tag, compressor terminals, wiring/contactor/capacitor area, and any visible damage.

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Inspect all wiring: is there any damage to wires or terminals? *

Did the compressor fail any winding tests? *

If yes, perform an acid test of the compressor oil.

Inspect compressor contactor: are the contact points burned? *

Was acid detected in the compressor oil? *

When the system is opened to atmosphere, install a replacement liquid line drier. If acid is detected with an acid test kit, install a suction line filter drier.

Is a liquid line drier installed? *

Where is the liquid line drier installed? *

Outside near Outdoor Unit
Inside Near Evaporator Coil

Compressor Mechanical Tests

Note

Before mechanical testing, reconnect the compressor and unit wiring according to the unit electrical wiring diagram.

With the unit connected to electrical power, will the compressor operate? *

If no, return to the compressor winding checks and verify readings at the compressor terminals.

Compressor Pressure Information

Discharge pressure at the liquid line service valve (psig) *

The small pipe

Liquid line temperature at the liquid line service valve (°F) *

The small pipe

Suction pressure at the vapor line service valve (psig) *

The large insulated pipe

Vapor line temperature at the vapor line service valve (°F) *

The large insulated pipe

Pumpdown test

Close the liquid line service valve and watch the suction/low-pressure gauge. Let the unit operate until one of the following occurs:

5 minutes of continuous operation with minimal pressure change
Compressor cycles off on internal overload/high temperature
Unit cycles off on low pressure, typically between 15–35 psig
No low pressure switch is present and suction pressure drops to approximately 0–10 psig

For scroll compressors, sound may increase at lower pressures and the compressor may not pull completely to 0 psig as the scroll plates separate due to low pressure differential. This can be normal, but the compressor should be able to get below 30 psig.

Will the unit pump down to a low pressure between 0–30 psig? *

If the cause of compressor failure is not determined and corrected, the replacement compressor may fail.

Oil inspection note

Since the inside of a hermetic compressor is not visible, compressor oil can provide useful information about the cause of failure. Use a clean, marked container to inspect oil quantity and clarity.

Check the compressor data tag for oil quantity.
Place the removed compressor on a secure tailgate or bench.
Slowly tip the compressor toward the open suction stub.
Capture the used oil in a clean, marked container.
Inspect oil clarity and quantity.
After inspection, pour the oil back into the failed compressor suction stub.

For additional compressor pressure and temperature testing, refer to the System Analyzer Form.

Final troubleshooting notes / suspected cause of failure *

Technical Support Review

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