Fantech ATMO Series, Installation And Operation Manual

6

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.  In order to provide proper distribution of the fresh air, it is 

recommended that the furnace blower be set to run continuously or 
interconnected with FAA.

 See furnace electrical connection on page 

16.

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 FAA and the equipment 

it is being connected to the FAA's airflow must be balanced on site, 
using the procedure found in the section “AIRFLOW BALANCING”

* In the case of a multi-zone system, please contact Fantech customer 

service prior to installing any installation type requiring the use of the 

furnace interlock"

FAA/Furnace ducting for Partially Dedicated System

Air from inside

* Unit air flow should be balanced while FAA is on "Normal" speed and 
furnace blower is running.

Air return

Cold air 

return

* Ductwork layout may dif-
fer depending on model

Stale air to

outside

Fresh air from

outside

Fresh air to
living areas

Fantech fresh air applicance (FAA or HRV/ERV) 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 FAA supply air duct to a furnace's return air duct, the FAA 

must operate continuously. When the FAA is turned off, no warm exhaust air will flow 

through the FAA 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.

If the FAA is installed such that the homeowner may turn off the FAA during the winter, we 

recommend installing a motorized damper between the FAA's supply air and the furnace's 

return air duct that closes when the FAA is not operating. See wiring diagram (figure 1). 

You may also choose to use a Fantech FAA that uses a recirculation defrost that incorpo-

rates an outdoor air damper. 

Damper 
Motor

24 VAC Transformer

COM

NO

HRV Furnace interlock
See page 16.

24V

120V

Figure 1

*Transformer and Damper motor not included

Make sure the FAA is 

capable of meeting the

required airflow rate.