Simplified Installation - Fantech VHR150 Installation Manual

INSTALLATION EXAMPLES (CONT'D)
DIRECT CONNECTION of both the HRV SUPPLY AIR STREAM and EXHAUST AIR STREAM
to the FURNACE COLD AIR RETURN
SIMPLIFIED INSTALLATION (GOOD)
(RETURN/RETURN METHOD) - OPTION 1
1. Furnace blower must operate when ventilation from HRV is required. The
furnace should be set to run continuously or interlocked with HRV.
2. A minimum separation of 1m (3`3'') is recommended between the two
direct connections.
3. In order to prevent exhausting any fresh air, the HRV's exhaust air connection
should be upstream of the HRV's supply air connection when ducting to the
furnace's cold air return.
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"
HRV/ furnace for Simplified Installation – Option 1
Outside
Stale air to
outside
Fantech heat recovery ventilators (HRV) that use a supply fan shutdown for frost preven-
tion do not include an outdoor air motorized damper. If you are using a simplified installa-
tion, 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.
If the HRV is installed such that the homeowner may turn off the HRV during the winter, we
recommend installing a motorized damper between the HRV's supply air and the furnace's
return air duct that closes when the HRV is not operating. See wiring diagram (figure 1).
You may also choose to use a Fantech HRV that uses a recirculation defrost that incorpo-
rates an outdoor air damper.
Stale air from inside
Fresh air from
outside
* Unit airflow should be balanced while HRV is on
"Normal" speed and furnace blower is running.
1 m (3' 3") min.
recommended
1 m (3' 3")
Motorized
Damper
mended
Fresh air to
living areas
Cold air
return
Figure 1
*Transformer and Damper motor not included
Suggested installation for:
• When bathroom and kitchen
already have local exhaust
system
• May be suitable for
retrofitting
Benefits: Least expensive
installation type
min.
recom-
24 VAC Transformer
24V
120V
NO
COM
HRV Furnace interlock
See page 16.
7
Damper
Motor
fantech