Thermific®
Do not manifold two (2) or more units into a common sidewall vent system without provisions for additional forced draft.
3.0INSTALLATION
3.1COMPONENTS PROVIDED
The direct vent/sealed combustion option is shipped with the following items shipped loose for field installation:
Custom 6 inch diameter to 12 inch diameter transition duct with extension, for attachment to the combustion air inlet on the boiler.
A 12" inlet damper assembly with actuator and limit switch mounted to the damper shaft.
Auxiliary Control Panel to operate the inlet damper assembly.
The inlet damper assembly and control panel will prevent the flow of cold air through the boiler during the off cycle and prevent freeze up and "off cycle" losses. The use of these two items is optional.
3.2COMBUSTION AIR INLET SYSTEM
Note:
3.2.1 System Design - Pressure Drop
The air inlet duct system shall be designed for a maximum pressure drop of 0.05" W.C. taking into account the equivalent length of all fittings. Refer to Section 3.4.5 for equivalent length of fittings.
3.2.2 Inlet Duct
Materials shall be single wall galvanized duct (minimum thickness 26 gauge) or PVC duct tubing (0.187 inch wall thickness) only. No substitutions.
3.2.2.1 Single Wall Galvanized Duct
Proper sealing of the tubing is necessary to prevent flow of combustion air from conditioned space. If single wall galvanized tubing is used, GE RTV 102
Installation
silicone sealant, or equivalent, must be used on each circumferential and horizontal joint before joining together. At least 24 hours must be allowed for cure of this sealant and proper bond. Cure time can be reduced through the application of heat (See instructions provided with the sealant). After the cure period, each joint must be wrapped with an aluminum tape which is faced on the contact side with an adhesive.
3.2.2.2 PVC Duct
Proper sealing of the tubing is necessary to prevent flow of combustion air from conditioned space.
The installation must follow the vent manufacturer's instructions in all respects including proper joining and sealing of the tubing and fittings. Clearances to combustible materials and installation of firestops must conform to applicable codes.
3.2.3 Air Inlet Termination
Centering |
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Support |
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| Cover Plate |
Plate |
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| Sealant |
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| Termination |
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Sealant
12" Min. | Field Provided |
Inlet Screen |
The boiler combustion air inlet duct must be fitted with a termination device meeting the requirements of ANSI Z21.13. There are four recommended sidewall terminations:
•Double wall B vent 90 degree elbow, or
•Two double wall B vent 45 degree elbows, or
•Schedule 40 PVC 90 degree elbow, or
•Properly engineered intake louver screen.
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