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NTI · Boiler

3 P9 Scheduled maintenance: call for service

Normal status TRX

What the display is showing

Scheduled service reminder. Reset it with parameter 852.

Applies to: TRX150

What to do

  1. Reset the error with parameter 852.

Models that show this code

5 models in TRX

TRX085TRX110CTRX150TRX199TRX199C

Other codes on the same units

  • 03 05 PCB internal error
  • 03 06 PCB internal error
  • 03 07 PCB internal error
  • 03 09 Gas relay check failed
  • 4 11 Room sensor open or short circuit, Zone 1
  • 4 12 Room sensor open or short circuit, Zone 2
  • 4 13 Room sensor open or short circuit, Zone 3
  • 4 30 Detected accessory wired to BUS connection

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Source: NTI TRX150 manual, p. 91. Summarized in our own words; check the original manual for your model.

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.