Welcome to Field Controls:
HRV / ERV Training
Duct Systems
Part 3
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Introduction
HRV – ERV Duct Systems
A. Simplified System
B. Partially Dedicated System
C. Fully Dedicated System
D. Design Tips
E. Installation Considerations
F. Test
G. Review and Comments
Simplified System
Turn to the “Simplified Installation”
page 14 in the Instruction Manual
Simplified Installation
Return / Return Method
Fresh
Air to
Inside
Return Air
Duct
Fresh Air from
Outside
Stale Air to
Outside
Stale Air
from Inside
HVAC
Equipment
Ventilation System must be electrically interlocked with HVAC Equipment Fan
Simplified Installation
Simplified Installation
HVAC
Equipment
Note: New construction seal all metal ducts with mastic for Energy star 3.0 pressurized duct test
Partially Dedicated System
Page 15
Partially Dedicated System
Stale Air
from Inside
Fresh
Air to
Inside
Return
Air
Fresh Air
from
Outside
Stale Air to
Outside
HVAC
Equipment
Page 15
Partially Dedicated Installation
New Construction: Energy Star 3.0 requires the duct system to be pressure tested
Page 15
Partially Dedicated Installation
HVAC Equipment
Note: Seal all metal ducts with mastic to pass a pressurized duct test according to Energy Star 3.0
Fully Dedicated System
Page 16
Fully Dedicated Installation
Stale Air
from Inside
Fresh Air
Intake
Stale Air
Exhaust
Fresh Air
to Inside
Fully Dedicated Installation
Fully Dedicated Installation
Design Drawing Tips
• Include all branches and connections
Design tips:
o Minimize duct lengths
o Minimize bends
o Use 45° elbows instead of 90°
o Use “Y” s instead of a Tees
o Join the unit and duct system with
non-metallic insulated duct 12
inches in length (noise / vibration)
4 - Installation
Considerations
• Fresh air intake and stale
air exhaust locations
• Condensate drainage
• Space is conditioned
Not below 60°F
Not above 100°F
• Access for service
Maintenance / Cleaning
Ducts:
• Keep duct runs short
• Minimize 90° elbows
• 45° elbows preferred
• Y’s instead of tees
• Rigid duct recommended
• Energy Star homes use mastic to seal duct joints
Duct Systems Test
1. Flex duct must be stretched tightly
and supported properly with
appropriate hangers.
True or False
2. Metal duct seams should be sealed
with mastic to pass a Energy star 3.0
pressurized duct leakage test?
True or False
3. When installing a HRV or ERV in
conjunction with an existing forced air
HVAC system you will use:
A.
B.
C.
D.
E.
Partially Dedicated Installation Method
Simplified Installation Method
Fully Dedicated Installation Method
Partially Dedicated or Simplified Installation Method
None of the above
4. When installing an HRV or ERV without
a ducted forced air system you will use:
A.
B.
C.
D.
E.
Partially Dedicated Installation Method
Simplified Installation Method
Fully Dedicated Installation Method
Partially Dedicated or Simplified Installation Method
None of the above.
5. Simplified Installation: stale air is
exhausted from the return air of the
ducted HVAC equipment and an
equal amount of fresh air is replaced
back into the return air.
True or False
6. Another name for a Simplified Installation
A.
B.
C.
D.
E.
The Supply Return Method
The Return / Supply Method
A Partially Dedicated System
The Return / Return Method
None of the above
7. A Simplified Installation does not require
the furnace blower to run continuously or
be electrically interlocked with the HRV
or ERV.
True or False
8. Partially Dedicated System: stale air is
exhausted from specific locations
(bathroom, kitchen etc) and an equal
amount of fresh air is replaced back into
the HVAC system return air.
True or False
9. Install a backdraft damper on:
A.
B.
C.
D.
E.
Partially Dedicated Installation
Simplified Installation
Fully Dedicated Installation
Partially Dedicated and Simplified Installation
None of the above.
10. A Fully Dedicated System is
normally installed in homes without
a ducted forced air system.
True or False
11. On a Fully Dedicated Installation
the supply ducts deliver fresh air to
bathrooms, kitchen, laundry room, etc.
True or False
12. Resistance to air flow is called
External Static Pressure (e.s.p.)
True or False
13. General installation considerations are
A.
B.
C.
D.
E.
F.
Fresh air intake and stale air exhaust locations
Condensate drainage
Install unit in the conditioned space
Provide access for service and maintenance
All the above
None of the above
14. Energy Star Homes
A.
B.
C.
D.
E.
F.
Seal duct joints and fittings with foil tape
Seal duct joints and fittings with duct tape
Seal duct joints and fittings using screws or rivets
Seal all duct joints with mastic
All the above
None of the above
15. Energy Star Homes
A.
B.
C.
D.
E.
F.
A recognized label for energy efficient homes
Require ventilation according to ASHRAE 62.2
Require a pressurized duct leakage test
Require manual J load calculations
All the above
None of the above
Questions