5715184-BIM-A-0519
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Johnson Controls Ducted Systems
Ventilated Combustion Air
(Modular Home Installations Only)
The ventilated attic space or a crawl space from which the combustion
air is taken must comply with the requirements specified in “COMBUS-
TION AIR SOURCE FROM OUTDOORS” in this instruction or in Sec-
tion 5.3, Air for Combustion and Ventilation of the National Fuel Gas
Code, ANSI Z223.1 (latest edition). This type of installation requires two
properly sized pipes. One brings combustion air from a properly venti-
lated 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 build-
ing. Refer to Table 6 for intake pipe sizing, allowable length and elbow
usage. Follow all notes, procedures and required materials in the
SEALED COMBUSTION AIR SUPPLY section in these instructions
when installing the combustion air pipe from the unit and into a venti-
lated attic space or crawl space. DO NOT terminate vent pipe in an Attic
or Crawl Space.
Ventilated Combustion Air Termination
(Modular Home Installations Only)
Refer to Figure 30 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 in. (30.5 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 in. (0.63 cm) 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.
VENT BLOWER ROTATION
For ease of venting, the vent blower may be rotated 90° in either direc-
tion. For upflow installations the vent may exit through the top or either
side of the cabinet. For downflow installations, the vent blower must be
rotated so that the vent exits through either side of the cabinet. See Fig-
ures 19–20 for illustrations of different inducer rotation positions.
WARNING
CARBON MONOXIDE POISONING HAZARD
Failure to follow the steps outlined below for each appliance connected to the venting system being placed into operation could result in carbon-
monxide poisoning or death.
The following steps shall be followed for each appliance connected to the venting system being placed into operation, while all other appliances
connected to the venting system are not in operation:
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 contin-
uously.
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 open-
ing 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, fire-
place 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 40 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 (outside) air system must be in accordance with the National Fuel Gas Code
Z223.1 or CAN/CGA B149.1 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.
!
FIGURE 30:
Attic and Crawl Space Combustion Air Termination
´0,1
´0,1,080
%(7:((1%27720
2)$,5,17$.($1'
$1<0$7(5,$/%(/2:
$
WARNING
Be sure to instruct the owner not to block this intake pipe.
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