Gas Furnace Diagnostic Report

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Contact & Routing – Step 1 of 10

This form follows the furnace sequence of operation and collects the measurements, observations, and evidence needed for Carrier Enterprise Technical Service & Support to assist with diagnosis.

Safety: Follow all manufacturer instructions and applicable codes. Stop operation and follow appropriate safety procedures for suspected gas leaks, unsafe combustion, flame rollout, elevated carbon monoxide, venting failure, or other hazardous conditions.

Please select your region. *

Dealer / Company Name *

Dealer Account Number *

Technician Name *

First

Last

Technician Mobile Phone *

Technician Email *

Are you currently at the job site? *

Are you currently working with a Technical Support Representative? *

Case Number or Technical Support Representative Name

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Job Site / Customer Information

Job Site / Customer Name *

Job Site / Customer Address *

Address Line 1

Address Line 2

City

State / Province / Region

Postal Code

Country

Installation / Start-Up Date

Concern / Failure Date *

Furnace Identification & Rating Plate

Furnace Brand *

Furnace Model Number *

Furnace Serial Number *

Furnace Configuration *

Single Stage
Two Stage
Modulating

Fuel *

Natural Gas
Propane

Conversion Kit Part Number *

Enter the installed approved conversion kit part number.

Conversion Label and Instructions Verified? *

Furnace Application *

Furnace Orientation *

Thermostat / Control Type *

Is the system zoned? *

Zoning Panel / Control Model

Installed Accessories

Humidifier
Dehumidifier
Electronic Air Cleaner
UV Device
Fresh-Air Ventilator
Other

Previous Service History / Parts Already Replaced

Furnace Nameplate and Installation Photos

Drag & Drop Files, Choose Files to Upload You can upload up to 6 files.

Upload clear model/serial, rating plate, conversion label, furnace installation, and control-board photos.

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Reported Concern

Select all concerns that apply. *

No Heat / Furnace Will Not Start
Intermittent Operation / Lockout
Insufficient Heat
Excessive Temperature Rise / Limit Trips
Noise
Odor
Combustion / Flame Concern
Venting Concern
Condensate Concern
Other

Describe the concern in the technician’s own words. *

Current Active Fault Code

correctly? (in. suspected?

Stored / Previous Fault Codes

Where does the furnace sequence stop? *

Is an unsafe condition suspected? *

Yes — Operation Stopped
No
Unsure

Describe the suspected unsafe condition. *

Fault-Code and Control-Board Evidence

Drag & Drop Files, Choose Files to Upload You can upload up to 6 files.

Upload fault-code displays, board status, wiring, thermostat/control, and relevant video or photos.

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Power, Controls & Call for Heat

Line Voltage at Furnace (VAC)

Equipment Ground Verified? *

Yes
No
Not Tested

Transformer Primary Voltage (VAC) *

Transformer Secondary Voltage (VAC) *

R to C Voltage (VAC) *

W1 to C Voltage During Heat Call (VAC) *

W2 to C Voltage During Heat Call (VAC)

Control Fuse Condition *

Good
Open / Failed
Not Tested

Valid Call for Heat Confirmed at Furnace? *

Yes
No
Not Tested

Control Board Powered and Responding? *

Yes
No
Intermittent
Not Tested

Control Board Status / LED Indication

Factory Wiring Verified Against Furnace Wiring Diagram? *

Yes
No
Not Completed

Was a failure identified in this section? *

Power / Control Failure Details *

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Inducer & Pressure-Switch Sequence

Does the inducer receive an operating command? *

Yes
No
Not Tested

Inducer Voltage While Commanded (VAC)

Does the inducer start and remain running? *

Yes
No
Intermittent
Not Tested

Inducer Operating Amperage (A) *

Measured Draft / Negative Pressure at Pressure Switch (in. wc.) *

Pressure Switch Open Before Inducer Starts? *

Yes
No
Not Tested

Pressure Switch Closes After Inducer Starts? *

Yes
No
Intermittent
Not Tested

Venting, Intake & Condensate

Vent Material *

Vent Diameter and Configuration *

Approximate Equivalent Vent Length (ft) *

Vent / Intake Termination and Installation Observations

Vent or Intake Restriction / Recirculation Suspected? *

Yes
No
Not Determined

Condensate Trap and Drain Condition *

Clear / Properly Installed
Restricted / Improper
Not Applicable
Not Tested

Condensate Trap Primed and Collector / Tubing Clear? *

Yes
No
Not Applicable
Not Tested

Was a failure identified in this section? *

Inducer / Venting / Condensate Failure Details *

Venting, Pressure, and Condensate Evidence

Drag & Drop Files, Choose Files to Upload You can upload up to 8 files.

Upload manometer readings, vent/intake termination, condensate trap, tubing, collector, and installation photos.

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Ignition, Gas Valve & Flame Proving

Is the igniter energized? *

Yes
No
Not Tested

Igniter Voltage While Energized (VAC) *

Igniter Resistance (Ω) *

Igniter Condition *

Glows / Sparks Normally
Weak / Damaged / Contaminated
No Operation
Not Tested

Is the gas valve energized? *

Yes
No
Not Tested

Gas Valve Voltage During Ignition Trial (VAC)

Do all burners ignite and cross-light correctly? *

Yes
No
Intermittent
Not Tested

Burner Flame / Cross-Lighting Observations

Flame-Sensor Current (µA DC)

Does flame prove and remain established? *

Yes
No
Intermittent
Not Tested

Seconds Until Flame Loss or Lockout

Gas Pressure & Combustion

Combustion-Test Status *

Combustion testing is required for combustion, odor, venting, rollout, and limit concerns.

Explain Why Combustion Testing Was Not Completed *

Measured Inlet Gas Pressure — Furnace Off (in. wc.)

Measured Inlet Gas Pressure — Operating (in. wc.)

Measured Low-Stage Manifold Pressure (in. wc.)

Measured High-Stage / Single-Stage Manifold Pressure (in. wc.)

O₂ (%)

CO₂ (%)

Carbon Monoxide — Air Free (ppm)

Flue Temperature (°F)

Draft / Vent Pressure (in. wc.)

Excess Air (%)

Combustion Efficiency (%)

Combustion Analyzer and Manometer Results

Drag & Drop Files, Choose Files to Upload You can upload up to 8 files.

Upload analyzer printouts/screens, manometer readings, burner/flame photos, and gas-pressure evidence.

Was a failure identified in this section? *

Ignition / Gas / Combustion Failure Details *

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Indoor Blower & Airflow

Does the indoor blower start and remain operating? *

Yes
No
Intermittent
Not Tested

Blower Motor Type *

Heating Airflow / Speed / Tap / Command Setting

Blower Voltage (VAC) *

Blower Operating Amperage (A)

Static Pressure

Return Static Pressure (in. wc.)

Supply Static Pressure (in. wc.)

Static Pressure After Furnace / Before Coil (in. wc.)

Static Pressure After Coil (in. wc.)

Total External Static Pressure — TESP (in. wc.)

Filter Pressure Drop (in. wc.)

Measured or Calculated Airflow (CFM)

Static Pressure Review

Automatically compares TESP with the entered rated maximum.

Temperature Rise & Limit Operation

Return-Air Temperature (°F)

Supply-Air Temperature (°F)

Calculated Temperature Rise (°F)

Supply-air temperature minus return-air temperature.

Temperature-Rise Review

Automatically compares calculated rise with the entered nameplate range.

Limit-Switch Status During Test *

Remains Closed
Opens / Trips
Intermittent
Not Tested

Limit, Rollout, Airflow, Filter, or Duct Observations

Airflow, Static Pressure, and Temperature Evidence

Drag & Drop Files, Choose Files to Upload You can upload up to 8 files.

Upload manometer readings, temperature probes, filter, blower, coil, duct, and airflow evidence.

Was a failure identified in this section? *

Blower / Airflow / Temperature-Rise Failure Details *

Continue collecting the remaining operating data? *

Yes
No — Continue to final report

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Two-Stage / Modulating Operation

This section appears only for two-stage or modulating furnaces.

Does low-stage operation function correctly? *

Yes
No
Intermittent
Not Tested

Does high-stage operation function correctly? *

Yes
No
Intermittent
Not Tested

Does the furnace transition between stages correctly? *

Yes
No
Intermittent
Not Tested

Low-Stage Measured Temperature Rise (°F)

High-Stage Measured Temperature Rise (°F)

Low-Stage Measured Airflow (CFM)

High-Stage Measured Airflow (CFM)

Observed Modulation Command / Capacity (%)

Stage / Modulation / Communication Observations

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Diagnostic Handoff to Technical Support

Review the calculated measurement checks below. These checks compare only against the rating-plate limits entered in this form. They do not replace manufacturer service instructions or a complete safety evaluation.

Measurements Not Obtained and Why

Technician Observations / Suspected Cause

Tests, Adjustments, or Repairs Already Performed

Equipment Operating Status When Technician Leaves *

Is Immediate Technical Support Contact Requested? *

Diagnostic Measurement Summary

Automatically populated from the calculated comparisons.

Additional Installation / Diagnostic Photos or Videos

Drag & Drop Files, Choose Files to Upload You can upload up to 10 files.

Upload any remaining evidence that will help Technical Support evaluate the furnace.

Technician Confirmation *

I confirm the entered measurements were taken from this equipment and the report is complete to the extent testing could be safely performed.

After submission, the report will be routed to the selected regional Technical Service & Support team. A copy will be emailed to the technician, and an optional customer copy will be sent when a customer email is provided.

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This furnace is configured as single stage. Two-stage and modulating checks do not apply. Select Next to continue to the diagnostic handoff.

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