6
HRV/ Furnace ducting for Partially Dedicated System
Stale air from inside
* Unit airflow should be balanced while HRV is on
“Normal” speed and furnace blower is running.
Outside
Fresh air
to living
areas
1 m (3' 3")
min.
recommended
Cold air
return
Stale air to
outside
Fresh air from
outside
Installation examples
(Cont'd)
DIRECT CONNECTION of the FRESH air to living area to the RETURN PLENUM
of the AIR HANDLER (Stale air drawn from key areas of home)
PARTIALLY DEDICATED SYSTEM (BETTER)
Suggested installation for:
• Central furnace (air
handling unit or central
air conditioners)
• When ducting fresh
air to living area is not
possible or practical,
i.e. expensive or when
the central AHU will
operate year-round.
Benefits:
Conditions the
fresh air prior to
distributing it throughout
the house
1. Furnace blower must operate when ventilation from HRV is required. The
furnace should be set to run continuously or interlocked with HRV
2. Stale air is drawn from key areas of the home (bathroom, kitchen, laundry
room).
3. Fresh air is supplied to the return air plenum of the furnace.
4. Due to the difference in pressure between the HRV and the equipment it
is being connected to the HRV’s airflow must be balanced on site, using
the procedure found in the section “AIRFLOW BALANCING”
Fantech heat recovery ventilators (HRV) that use a supply fan shutdown for frost prevention do not include an outdoor air motorized damper. If
you are using a simplified installation, i.e. connecting the HRV supply air duct to a furnace's return air duct, the HRV must operate continuously.
When the HRV is turned off, no warm exhaust air will flow through the HRV but the furnace's fan will continue to draw in outdoor air directly into
the furnace. If it's cold outside, cold air will be introduced, without re-heating, directly into the furnace.