HRV not interlocked with furnace fan

Insulation · Ventilation Systems · printed page 255 (PDF page 256)

Original page Sign in to save

Book index entries

Furnace Fan not Interlocked with HRV not Interlocked with Furnace Fan

Text in the illustration

if the furnace fan isn't running when the HRV is on, the airflow can short circuit in the cold air return
cutaway showing inside of cold air return
AIRFLOW
cold air return
gas furnace
fresh air
exhaust
HRV
cold-side ducts
when the HRV is on, the furnace fan should operate on low speed (if it's a multiple speed blower)
when the HRV switches to high speed (house ventilation setting) the furnace fan should also switch to high speed

Generated explanation

The illustration shows a heat recovery ventilator (HRV) connected to the cold-air return duct of a gas furnace, with separate fresh-air and exhaust connections and two cold-side ducts. A cutaway in the return duct shows how airflow can short circuit between the HRV connections when the furnace fan is not running. Arrows indicate airflow through the ducts and toward the furnace. The annotations specify that the furnace fan should run on low speed when the HRV operates, and switch to high speed when the HRV switches to its high-speed house ventilation setting.

Related illustrations

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

1354

HRV (heat recovery ventilator) components

· p. 243

The schematic shows a heat recovery ventilator connected through an exterior wall to fresh-air intake and exhaust ducts, with two additional ducts serving the house. Arrows show cool fresh air passing through the heat ex