NTI · Boiler

1 P2 Insufficient circulation or missing water (warning)

Normal status TRX

What the display is showing

Supply minus return temperature above 99 °F. Warning only.

Applies to: TRX150

Good to know

Low water pressure
Air in the system

Models that show this code

5 models in TRX

TRX085TRX110CTRX150TRX199TRX199C

Other codes on the same units

1 12 CH return temperature probe open or short circuit
1 14 External (outdoor) sensor open or short circuit
1 16 Floor thermostat contact open
1 P1 Insufficient circulation or missing water (warning)
1 P3 Inadequate circulation or missing water (warning)
02 01 Damaged or shorted DHW temperature probe
02 03 Storage temperature probe open or short circuit
02 05 DHW inlet probe open circuit

Save it for the next call

Star this code in the HVACopedia app and keep the whole library on your phone for jobs with no signal.

Open the app

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.