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NTI · Boiler troubleshooting

Replace the gas valve

TRX150

What is going on

Swapping the gas valve on the TRX150 is a straightforward job if you take it in order, but it is gas, so it belongs to a licensed technician. You get to the valve by removing the gas pipe the same way you would for cleaning the combustion chamber, and new sealing rings go in every time.

Likely causes

  • Gas valve not opening, or leaking internally
  • Old sealing rings no longer sealing after the valve is disturbed
  • Gas pipe not seated properly after reassembly

Check in this order

  1. Turn off power and close the gas shutoff, then remove the gas pipe as described in the combustion chamber cleaning procedure.
  2. Disconnect the electrical connection from the gas valve.
  3. Remove the two nuts above and below the gas valve.
  4. Take the gas valve out.
  5. Install the new valve in reverse order using new sealing rings.
  6. Check every joint for gas leaks before you leave.

Applies to: TRX150

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Source: NTI TRX150 manual, p. 100. 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.