Carrier HRVCCLHA Installation Instructions Manual page 4

Maximum length of duct for the system should be designed
according to the highest speed of the unit. Refer to specifications
listed in unit Product Data for ventilation capacities.
Forced- -Air Application
Most HRV applications will be installed in conjunction with new
or existing forced- -air system. To operate properly, the fresh- -air
supply and stale- -air return from HRV connect directly to return- -air
duct system. This is how the HRV distributes fresh air and removes
stale air from inside of building (see Fig. 9). For these installations,
furnace or fan coil blower must be interlocked and operate
continuously whenever HRV is energized.
Interlock relay is now integrated into the control and is designed to
interlock HRV with indoor equipment blower. When HRV is
energized, R and G circuit inside of furnace or fan coil will
energize.
NOTE: The fresh air from HRV is introduced into return- -air duct
at a point no less than 6 ft (1.8 m) upstream of furnace or fan coil.
This connection should be direct (see Fig. 9). This is to allow
incoming fresh- -air to mix before entering indoor equipment.
Connect Ducts to HRV
CAUTION
!
PROPERTY DAMAGE HAZARD
Failure to follow this caution may result in minor property
damage from sweating duct or loss of unit efficiency and
capacity.
If HRV duct work is installed in an unconditioned space,
insulated flexible duct is required.
Insulated flexible duct is required on both fresh- -air inlet and
exhaust- -air outlet ducts connecting to exterior wall. When
using insulated flexible duct, the vapor barrier of the flexible ducts
must be taped very tight to prevent condensation problems. To
A
B
FURNACE
ERV
REAR
INLET HOOD
6 ft / 1.8 m
Fig. 9 - - Exhaust Ventilation
NOTE: A + B = Not less than 10 ft / 3 m
3 ft / .9 m MIN
INSULATED DUCT CONNECTING
FRESH AIR & EXHAUST TO
OUTSIDE
NOTE: Supply & exhaust ducts have
internal balancing dampers
that must be adjusted.
EXHAUST HOOD
18" / 457 mm
GROUND LEVEL
reduce pressure drop, stretch the flex duct and support it in a proper
manner to avoid reduced airflow.
When connecting the HRV to a return- -air duct system, insulated
flexible duct can be used. However, when metal or rigid ducts are
applied use approximately 18- -in. (457 mm) of flexible duct at
HRV ports for fresh- -air supply, and stale- -air return. When using
metal duct from fresh- -air supply to system duct work, the metal
duct should be insulated (see Fig. 10). This can act as a silencer
when connecting ducts to return- -air duct system. This should
eliminate transmission of noise or vibration from unit to main duct
system.
FLEXIBLE
DUCT
FRESH-AIR
SUPPLY
DUCTS CONNECTING TO
RETURN-AIR DUCT SYSTEM
Fig. 10 - - Flexible Duct Fit- -Up
NOTE: Balancing dampers should be installed in stale- -air exhaust
and fresh air intake ducts before connecting to the HRVCCSVU
and HRVCCLVU units. The balancing dampers are provided in the
HRVCCLHA units (see balancing HRV section). Make sure both
balancing dampers are left in fully open position before connecting
the ducts to these ports. See Integrated balancing damper
illustration.
4
A07282
STALE-AIR
RETURN
A98382