271043-UIM-B-0707
18
Unitary Products Group
Vent and Supply (Outside) Air Safety Check Procedure
Follow the procedure in ANSI Z223.1 National Fuel Gas Code. Refer to
the section on the “Recommended Procedure for Safety Inspection of
an Existing Appliance” or in Canada B149.1-00 Natural Gas and Pro-
pane Installation Code section on “Venting Systems and Air Supply for
Appliances” and all local codes. In addition to the procedure specified in
ANSI Z223.1, It is recommended that you follow the venting safety pro-
cedure below. This procedure is designed to detect an inadequate ven-
tilation system that can cause the appliances in the area to operate
improperly causing unsafe levels of Carbon Monoxide or an unsafe
condition to occur.
1.
Inspect the venting system for proper size and horizontal pitch.
Determine that there is no blockage, restriction, leakage, corrosion
or other deficiencies, which could cause an unsafe condition
2.
Close all building doors and windows and all doors.
3.
Turn on clothes dryers and TURN ON any exhaust fans, such as
range hoods and bathroom exhausts, so they shall operate at
maximum speed. Open the fireplace dampers. Do not operate a
summer exhaust fan.
4.
Follow the lighting instructions. Place the appliance being
inspected in operation. Adjust thermostat so the appliance shall
operate continuously.
5.
Test each appliance (such as a water heater) equipped with a draft
hood for spillage (down-draft or no draft) at the draft hood relief
opening after 5 minutes of main burner operation. Appliances that
do not have draft hoods need to be checked at the vent pipe as
close to the appliance as possible. Use a combustion analyzer to
check the CO2 and CO levels of each appliance. Use a draft
gauge to check for a downdraft or inadequate draft condition.
6.
After it has been determined that each appliance properly vents
when tested as outlined above, return doors, windows, exhaust
fans, fireplace dampers and any other gas burning appliance to
their normal condition.
7.
If improper venting is observed during any of the above tests, a
problem exists with either the venting system or the appliance
does not have enough combustion air (Supply Air from outside) to
complete combustion. This condition must be corrected before the
appliance can function safely.
NOTE:
An unsafe condition exists when the CO reading exceeds 100
ppm and the draft reading is not in excess of - 0.1 in. W.C. (-25 kPa)
with all of the appliance(s) operating at the same time.
8.
Any corrections to the venting system and / or to the supply (out-
side) air system must be in accordance with the National Fuel Gas
Code Z223.1 or CAN/CGA B149.1-00 Natural Gas and Propane
Installation Code (latest editions). If the vent system must be
resized, follow the appropriate tables in Appendix G of the above
codes or for this appliance only refer to Table 8 of these instruc-
tions.
Ventilated Combustion Air
The ventilated attic space or a crawl space from which the combustion
air is taken must comply with the requirements specified in “AIR
SOURCE FROM OUTDOORS” in this instruction or in Section 5.3, Air
for Combustion and Ventilation of the National Fuel Gas Code, ANSI
Z223.1 (latest edition). This type installation requires two properly sized
pipes. One brings combustion air from a properly ventilated attic space
or crawl space and a second pipe that extends from the furnace vent
connection (top right of unit) to the exterior of the building. Refer to
Table 8 for intake pipe sizing, allowable length and elbow usage. Follow
all notes, procedures and required materials in the SEALED COMBUS-
TION AIR SUPPLY section in these instructions when installing the
combustion air pipe from the unit and into a ventilated attic space or
crawl space. DO NOT terminate vent pipe in an Attic or Crawl Space.
Ventilated Combustion Air Termination
Refer to Figure 18 for required attic termination for the combustion air
intake pipe. For attic termination, use two 90 elbows with the open end
in a downward position. Be sure to maintain 12” (30 cm) clearance
above any insulation, flooring or other material.
A crawl space combustion air installation consists of a straight pipe from
the PVC coupling on the burner box that extends into the crawl space
and terminates with a 1/4” (6.35 mm) mesh screen and no elbows.
Specially Engineered Installations
The above requirements shall be permitted to be waived where special
engineering, approved by the authority having jurisdiction, provides an
adequate supply of air for combustion and ventilation.
SECTION VII: CONDENSATE PIPING
The condensate drain connection is provided in the furnace for field
installation. It consists of a formed hose with a 1/2” (1.3 cm) NPT male
connection. A 1/2” (1.3 cm) FM x 3/4” (1.9 cm) PVC slip coupling is pro-
vided.
This drain hose may be installed to allow left or right side condensate
drain connection, refer to Figure 19. Cut the hose to allow for proper fit
for left or right exit. If necessary, trim the hose supplied to ensure that it
slopes downwards.
To install the drain hose assembly, remove the 7/8” (2.2 cm) knockout in
the side panel. Remove the conduit nut from the 1/2” (1.3 cm) male fit-
ting. Push the male fitting through the hole and reinstall the nut. The
use of the 3/4” (1.9 cm) PVC coupling is optional.
The condensate water will flow to the drain better if an open tee, or
short length of pipe is installed in the drain line, as shown in Figure 19.
IMPORTANT:
The condensate drain from the furnace may be con-
nected in common with the drain from an air conditioning coil if allowed
by local code.
IMPORTANT:
Condensate must be disposed of properly. Follow local
plumbing or wastewater codes. The drain line must maintain a 1/4" per
foot (0.635 cm per meter) slope to the drain.
FIGURE 18:
Attic and Crawl Space Combustion Air Termination
Be sure to instruct the owner not to block this intake pipe.
FIGURE 19:
Condensate Piping
12”
MIN.
12” MINIMUM
BETWEEN BOTTOM
OF BELOW AND
ANY MATERIAL
OPEN
TEE
OPEN
TEE
RH
DRAIN
LH
DRAIN
