32C-229 Orenstein duct test reults
474 Easthampton Rd. PO Box 1570
Northampton, MA 01060
413-584-3317
Duct Work Installation Worksheet
5-12-2016
Project:
Denise Orenstein
8 Hancock St
Northampton, MA
413-320-2581
Indoor Unit: Lennox Air Handler Unit (AHU), model CBX27UH-030-230-6-03, with TXV
Fan Speed: Medium
Outdoor Unit: 2 ½ ton Lennox XC14-030-230A10, with R410 refrigerant
Outdoor unit’s Sub Cool Goal: 6
Air filter- 5” Merv 11 made by Lennox
AHRI Certificate: 7513763, 16 SEER and 13 EER
Copper Line Set: ¾ and 3/8, approximately 34’, AHU approximately 20 feet above the
outdoor unit.
Scope: An older home is being retro-fitted with a newly designed and installed 2 ½ ton
central AC system. The new system is installed in the walk-up attic.
New system has one central return duct that pulls air from the entire home. The
return grille is located at the top of the stairwell on the second floor. There are 4
Supply grilles at the second floor ceiling and 2 metal duct runs were installed to offer
partial cooling to the 1st floor. There are a total of 6 supplies.
The AHU has a rugged safe pan under it and it has a water sensing shut off switch
that will break the power to the AHU fan call and the outdoor unit’s call for AC if
water is sensed.
All of the duct work is 26gg metal except very small sections of R8 Flex at the end
of the run-outs (maybe 4 to 6’ approximately).
Test Equipment:
Retrotec DU 200 duct tester, Retrotec DM2 manomater, TSI model 8371 Flow Hood
Duct Blast (pressure test)
The home is 1920 sq ft. At the required minimum of 4% duct leakage at 25 Pascals, the duct
system is allowed 76.8 cfm loss. This new duct system was tested at 26 Pascals and the leakage
rate was 74.45, which is a PASS. We did have small leaks that we simply couldn’t address to
make the system tighter (namely the return box where it connects at the second floor ceiling)
Duct Balancing:
Due to the old plaster and lath walls and ceiling we did not go the every area of the home with
our new duct routes. We had a total of 6 supplies:
Second Floor-
FRONT BED 168 CFM
MIDDLE BEDROOM 166 CFM
REAR BEDROOM 130 CFM
BATHROOM 65 CFM
First Floor
LIVING ROOM (FRONT) 197 CFM
KITCHEN 305 CFM
Total CFM measured is 1031
Gary Wilson, Owner
Wilson Services, Inc.
Northampton, MA
413-584-3317
413-626-5548
gary@wilsonph.com
www.wilsonph.com