[inov8]

Refer to the attached Avalon HVAC plenum diagram.

If airflow through the heater core (heat exchanger) is obstructed, then setting the temperature lower than ambient should move the blend dampers to position C and C', allowing air to bypass the obstruction. There should be a noticeable improvement in flow volume.

If airflow through the evaporator is obstructed, then setting the temperature lower than ambient should not significantly improve the airflow, since air flows through the evaporator for all blend damper positions.

If run without a filter, or with a deteriorated filter, particles are more likely to accumulate on the evaporator, since all air must pass through it before reaching the heater.

It might be possible to remedy an accumulation of particles by fabricating an adapter to force air through one of the face-level registers with an industrial blower, while blocking or closing all others, thereby establishing a reverse flow through the evaporator. If the filter is removed and the intake set to "fresh" in preparation for this endeavor, dislodged particles should exit to the exterior via the cowl opening.