Related illustrations

1256

Testing cold air returns

· p. 223

Two panels demonstrate testing airflow at a cold air return grille with a tissue. Panel A shows a hand holding a tissue next to the grille. Panel B uses an arrow to indicate that suction should pull the tissue toward the

1236

Evaporator coil - inspection procedures

· p. 219

The illustration shows a finned evaporator coil with warm indoor air entering at 75°F and cooled air leaving at 55°F for return to the house through ductwork. Blue and red refrigerant lines indicate cold liquid refrigera

0755

Fan cover missing

· p. 123

The illustration shows a forced-air furnace with its lower fan compartment cover missing, exposing the blower. Dashed outlines identify the cold-air return and supply plenum, and an air filter is shown beside the blower

0783

Electronic air cleaner problems

· p. 129

The illustration shows an electronic air cleaner installed in the cold-air return beside a gas furnace, with the supply plenum above the furnace. An exploded view shows the cleaner's prefilters and collecting cell betwee

1323

Heat recovery ventilator

· p. 236

The illustration shows a heat recovery ventilator with two blowers, a heat exchanger, controls, and ducts passing through an exterior wall. Colored arrows trace cool fresh outdoor air through the exchanger to become warm