MACH® Series | Installation |
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If air is taken from another interior space, each opening should have a net free area of 1 square inch for each 1,000 Btu per hour of boiler input (450 square inches for a 450,000 Btu per hour.)
3.6FLUE VENTING
This boiler requires a special vent system. This boiler is not certified for use with Type "B" vent.
This boiler is Category IV (condensing – positive pressure) as it is defined in ANSI Z21.13/CSA 4.9, latest edition. The vent material must be listed Category IV vent pipe (316L or
Vent installations shall be in accordance with Part 10, Venting of Equipment, of the National Fuel Gas Code, ANSI Z223.1 or CSA B.149 code, or applicable provisions of the local building codes.
The venting system and the horizontal portions of the venting system shall be supported to prevent sagging.
The vent must be sized according to the vent manufacturer’s recommendations. Consult your vent supplier for correct sizing and structural support requirements. Design calculations should be based on a maximum of 0.22" W.C. total frictional resistance in the stack (measured at the boiler flue gas discharge), with a stack temperature of 210° F (gross) and a CO2 level of 9% (natural gas) or 10.4% (propane). These values are to be used for vent sizing calculations.
The installation of a bird screen on the vent termination is recommended. Consult your local vent manufacturer for proper sizing.
3.6.1 Barometric Damper
WARNING!
Do not use a barometric damper with this boiler. (This is a positive pressure system; combustion gas may leak into the room.)
3.6.2 Flue Connection
The connection from the boiler to the vent should be as direct as possible and the upward slope of any horizontal breaching should be at least 1/4 inch per linear foot. The 300 and 450 vent connection incorporates a 4° slope toward the boiler to facilitate pitching of the vent for condensate collection. This boiler should not be connected into any portion of another mechanical draft system operating under positive pressure without consulting your local venting representative. Provisions must be made for supports to prevent contact of the vent with combustible surfaces.
Note: If the vent is erected directly behind the boiler, make sure that the weight of the vent is not supported by the boiler vent collar. The collar is not designed to support the weight of the vent. Structural support and spacing from combustible surfaces must be in accordance with the vent manufacturer's requirements.
Sidewall
Pitch toward boiler 1/4" per foot minimum.
4 degree slope toward boiler, approx. ¾” per foot.
Flue Connection at Boiler
3.6.3 Required Clearances
Provide clearances between combustion air intake, exhaust vent, roof and wall surfaces, doors and window, and snow line as shown in the following diagrams. The exhaust vent termination must be 14 feet above grade when located adjacent to a public walkway. It must also have a minimum 6 foot horizontal and 6 foot vertical clearance (above or below) any electric meters, gas meters, regulators, or relief equipment.
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