Trane · Furnace

E24 Internal communication error between ACM and CCM

Medium severity Trane S8V2

What the control is telling you

The two processors on the IFC lost communication. It shows briefly on a new replacement IFC until the model number is programmed.

Applies to: Trane S8V2 only

Likely causes

Replacement IFC not yet programmed
Internal IFC fault

Test and repair steps

On a replacement board, program the model number (Model Number Recovery menu or Link app).
Power off for one minute and restore.
If it does not clear, replace the IFC.

Settings for these units

Clearance to combustibles · Trane S8V2

Cabinet width	Vertical sides / top	Horizontal sides / top
14.5 in.	0 / 1 in.	1 / 2 in.
17.5 in.	0 / 1 in.	1 / 2 in.
21.0 in.	0 / 1 in.	1 / 3 in.
24.5 in.	0 / 1 in.	1 / 5 in.

24 in. front service access.

3 in. in front of the combustion air openings.

Return filter size by cabinet width · Trane S8V2

Cabinet width	Filter
14-1/2 in.	1 - 14 x 25 x 1 in.
17-1/2 in.	1 - 16 x 25 x 1 in.
21 in.	1 - 20 x 25 x 1 in.
24-1/2 in.	1 - 24 x 25 x 1 in.

Filters are field supplied and mounted outside the cabinet.

Over 1600 CFM upflow: return on both sides, one side plus bottom, or bottom only.

Models that show this code

12 models in Trane S8V2

S8V2A040M3PCBS8V2A040M3PDS8V2B060M4PCBS8V2B060M4PDS8V2B080M4PCBS8V2B080M4PDS8V2C080M5PCBS8V2C080M5PDS8V2C100M5PCBS8V2C100M5PDS8V2D120M5PCBS8V2D120M5PD

Other codes on the same units

E13 Blower motor size / OEM ID mismatch
E14 Configuration file error
E17 Blower motor communication error
E23 Menu data not received by combustion micro (CCM)
E25 Orientation sensor out of range
E26 Return static pressure sensor out of range or not connected
E27 Return air thermistor out of range or not connected
E28 Supply air thermistor out of range or not connected

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Source: Trane FNR-SVX003A-EN (S8V2 installer's guide) - section Integrated Furnace Control Display Codes, Table 37 Error codes; Trane FNR-SVX003A-EN (S8V2 installer's guide) - section Troubleshooting (flowcharts). Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.