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NTI · Boiler troubleshooting

Gas line installation requirements

TRX

What is going on

Gas line work must be done by a licensed professional. Confirm the boiler gas type matches the rating plate. This boiler must be converted for propane using the separate Gas Conversion Manual. Gas pipe connection is 3/4 in NPT and the pipe must not be smaller than 3/4 in. Do not use 1/2 in quick flex gas lines. Size the supply for the combined maximum BTU/hr of all appliances on the line.

Likely causes

  • Undersized or quick flex gas line
  • Gas type mismatch with the rating plate
  • Sulfur content above the limit

Check in this order

  1. Confirm the gas type on the rating plate matches the supply.
  2. Install a sediment trap (drip leg) at least 3 in long, accessible and protected from freezing.
  3. Install a manual gas shut-off valve close to the boiler.
  4. Install an approved gas union between the shut-off valve and the boiler 3/4 in NPT connection.
  5. Do not operate on gas with average sulfur above 30 mg/m3.
  6. Check the gas line inlet pressure and leak-test before firing.

Applies to: TRX150 gas connection

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Source: NTI TRX150 manual, p. 54-55. 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.