Tappan Low Supply Air Temperature

Furnace runs but house air feels cool or lukewarm from vents.

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

Blower speed too high, gas input too low, oversized ductwork, bypass humidifier left open on Tappan system

Safety: Do not adjust gas input yourself. Blower speed changes should follow the installation manual.

Steps:

Check that any bypass humidifier damper is set correctly for the season (usually OPEN in winter, but not bypassing excessive air).
Have a technician verify temperature rise across the furnace and adjust blower speed if necessary.
If the furnace is significantly oversized or ducts are very large, air may feel cooler even though the system is operating correctly.

Medium 3/5