American Standard Underfiring or Low Heat Output

Furnace runs but house never reaches set temperature, supply air feels lukewarm

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Low gas pressure, Partially plugged burner orifices, Incorrect manifold pressure setting, Wrong orifice size installed on American Standard furnace

Safety: Gas pressure and burner adjustments must be done by a licensed technician.

Basic homeowner checks:
- Ensure filter is clean and all registers are open.
- Verify thermostat is not in setback mode.
Professional service:
- Have a technician measure inlet and manifold gas pressure.
- Clean burner orifices and verify correct size per rating plate.

Professional Required 5/5

Burner Orifices

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