Installation & Service Manual
2Venting (continued)
Masonry Chimney Installation
A masonry chimney must be properly sized for the installation of a gas fired appliance. Venting of an appliance into a cold or oversized masonry chimney can result in operational and safety problems. Exterior masonry chimneys, with one or more sides exposed to cold outdoor temperatures, are more likely to have venting problems. The temperature of the flue gases from an appliance may not be able to sufficiently heat the masonry structure of the chimney to generate proper draft. This will result in condensing of flue gases, damage the masonry flue/tile, insufficient draft and possible spillage of flue gases into an occupied living space. Carefully inspect all chimney systems before installation. If there is any doubt about the sizing or condition of a masonry chimney, it must be relined with a properly sized and approved chimney liner system.
Inspection of a Masonry Chimney
A masonry chimney must be carefully inspected to determine its suitability for the venting of flue gases. A clay tile lined chimney must be structurally sound, straight and free of misaligned tile, gaps between liner sections, missing sections of liner or any signs of condensate drainage at the breaching or clean out. If there is any doubt about the condition of a masonry chimney, it must be relined. An unlined masonry chimney must not be used to vent flue gases from this appliance. An unlined chimney must be relined with an approved chimney liner system when a new appliance is be- ing attached to it. Metallic liner systems (Type “B” double wall or flexible or rigid metallic liners) are recommended. Consult with local code officials to determine code requirements or the advisability of using or relining a masonry chimney.
Sidewall Venting
This appliance is NOT approved for sidewall venting with the negative draft venting system as shipped from the factory. An induced draft fan MUST be used if the installation requires that the flue gases be vented out a sidewall. A properly sized and installed induced draft fan may also be used to vent the flue gases vertically if required by job site conditions. The induced draft fan must be listed by a nationally recognized test agency, be properly sized and installed per the recommendations of the induced draft fan manufacturer and meet local code requirements. Use care to ensure that the mechanically supplied draft does not exceed the range of a negative 0.02 to
0.05inches water column to ensure proper operation. If draft exceeds the specified range, the fan must be adjusted or the installation of a barometric damper in the flue may be required to properly control draft.
An induced draft fan MUST be interlocked into the appliance’s control circuit to start when the appliance calls for heat. The induced draft fan MUST also be equipped with a proving switch, properly interlocked into the appliance’s control circuit to prove fan operation before the main burners are allowed to fire. A vertical or sidewall vent termination for an induced draft fan MUST be installed per the recommendations of the fan manufacturer and provide proper clearances from any combustion or ventilation openings, windows, doors or other openings into the building. All induced draft fan installations must comply with local code requirements.
Fan Assisted Venting
A Power Venter kit is available on models 90,000 - 135,000 Btu/hr, water heaters only.
TABLE - 7B
VENT MATERIALS
Kit | Input | Material | |
Number | Btu / hr | ||
| |||
|
|
| |
KIT3104 | 90,000 | CPVC Rated | |
135,000 | CPVC Rated | ||
|
Minimum Vent Length = 12 Equivalent Feet *
(ALL UNITS)
Maximum Vent Length = 25 Equivalent Feet * *
(ALL UNITS)
*Equivalent Feet: 90° Elbow = 5 Feet
45° Elbow = 3 Feet
Figure 2-6_CW135 with Fan Assisted Venting
17 