AquaStar 125B NGS specifications Combustion AIR Requirements, Clearances

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WARNING: Flammable materials, gasoline, pressurized containers, or any other items or articles that are potentially fire hazards must NOT be placed on or adjacent to the heater. The appliance area must be kept free of all combustible materials, gasoline and other flammable vapors and liquids.

COMBUSTION AIR REQUIREMENTS

The AquaStar water heater holds cold water in its copper heat exchanger and brass water valve when not in use. Because of this, any cold air that comes in through the unit’s vent pipe is capable of freezing these components. This Installation Manual specifies the minimum vertical vent pipe and the amount of combustion air required for this unit. When all requirements are followed, the unit will operate properly and safely. However, there may still be a risk of freezing due to negative draft if all the combustion appliances in the area are not being supplied with a sufficient amount of make-up air. A wood stove or furnace can rob the make- up air in the AquaStar’s vent pipe, leaving the cold infiltrating air capable of freezing the cold water in the AquaStar heat exchanger. More make up air is the solution. Follow the instructions on venting and checking adequacy of make up air. A HVAC specialist should be used to design solutions for providing more make-up air if necessary.

Observe the following instructions concerning combustion air.

Appliances located in unconfined spaces:

a)An unconfined space is one whose volume is greater than 50 cubic feet per 1000 Btu per hour of the combined rating of all appliances installed in the space. That would be 5850 cubic feet for the AquaStar 125B “S” alone.

b)In unconfined spaces in buildings of conventional frame, masonry, or metal construction, infiltration is normally adequate to provide air for combustion, ventilation, and dilution of flue gasses.

Appliances located in confined spaces:

The confined space must be provided with two permanent openings, one commencing within 12 inches of the top and one commencing within 12 inches of the bottom of the enclosure. Each opening must have a minimum free area of one square inch per:

-1000 Btu/hr if all air is taken from inside the building.

-2000 Btu/hr if all air is taken from the outside by horizontal ducts.

-4000 Btu/hr if all air is taken from the outside by direct openings or vertical ducts.

Or the confined space must be provided with one permanent opening or duct that is within 12 inches of the ceiling of the enclosure. This opening must have a minimum free area of one square inch per:

-3000 Btu/hr if all air is taken from the outside by a direct opening or vertical duct.

Air Vents

(10 ¾ X 10 ¾ in. each)

 

125BS

 

125BS

 

Air Vents

 

(5 ½ X 5 ½ in. each)

 

 

Louvers, grills and screens have a blocking effect. If the effective free area is not known, increase the sizes of your openings by 75% if your louvers are wood and by 30% if your louvers are metal. Refer to the National Fuel Gas Code for complete information. In buildings of tight construction all air should be taken from outside.

CLEARANCES

The Aquastar 125 B “S” is design certified for installation on a combustible wall and for installation in an alcove or closet with the minimum clearances to combustible and non -combustible construction listed below

A.Top 12 inches (306 mm)

B.Front 4 inches (102 mm)

C.Back 0 inches

D.Sides 4 inches (102mm)

E.Bottom 12 inches (306 mm)

Clearance from vent is dependent upon the clearance rating of the venting material used. For example, type B-a vent is approved for 1 inch clearance.

Note: Typically, the minimum clearance to combustible materials should not be less than 6” for single wall flue pipe. Note that this clearance can be reduced if combustible materials are protected as per table VI of the National Fuel Gas Code or if Type B gas vent is used.

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Contents Table of Contents For Your SafetyRequired Natural Gas Pressure at inlet tap FeaturesUnpacking the Aquastar Heater TOP a Front B Back Sides Floor C Vent Diameter Front View Side ViewModel 125BS General Rules to Follow For Safe Operation Proper Location for Installing Your HeaterClearances Combustion AIR RequirementsAquastar 125 B S is design certified for mounting on a wall Mounting InstallationFigure a VentingFigure C 720 606 Masonry Chimneys6 Adaptor Used on High Altitude Vent Adaptor for High Altitude InstallationsFor LP GAS GAS Line Sizing For Natural GASMaximum Capacity of Semi-Rigid ColumnGAS Line Sizing Maximum Inlet GAS Flow Pressure SettingWater Connections Above 4.500 ft consult your local gas supplierOperating Instructions For Your Safety Read Before Lighting the PilotWhat to do if YOU Smell GAS To Turn OFF GAS to AppliancePilot burner with air screen/ pilot orifice Maintenance and ServiceAir in the Gas Line Pilot Lights but Flame Goes OUT When Button is ReleasedPilot Light will not Light Gas pressure too low Burners do not Ignite When HOT Water is Turned onWater is TOO HOT Water is not HOT EnoughUnbalanced pressure in waterlines HOT Water Temperature Fluctuates / Unit DeactivatedDiagram of AquaStar 125 BS Interior Components Diagram and Parts List Interior Components Diagram Parts List 125BS Flow chart of Aquastar 125 BS General Limited Warranty720 606 720 606 BBT North AMERICA, Waitsfield, VT all rights reserved Bosch Group