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NTI · Boiler troubleshooting

Condensate line blocked (display error)

TRX

What is going on

Boiler shows an error and won't run when the condensate line is blocked. No error code number is printed on these pages. Condensing boilers have to get rid of the water they make, and a frozen, kinked or flat line stops that. Common in cold weather where the line runs through an unheated space.

Likely causes

  • Condensate line frozen
  • Condensate line blocked or kinked
  • Condensate line not pitched properly
  • Trap dirty or overflow tee blocked

Check in this order

  1. Check the condensate line for freezing, kinks or blockage.
  2. Clear any blockage and confirm the line slopes down away from the boiler.
  3. Check the overflow tee and flexible tube for kinks.
  4. Thaw a frozen line gently and insulate or reroute it away from the cold.
  5. Clean the condensate trap as described in the Maintenance section (not on these pages).
  6. If the line cannot be cleared, have a qualified service technician repair it.

Applies to: TRX150

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Source: NTI TRX150 manual, p. 53. Written in our own words; check the manual for your exact 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.