Roberts Gorden WHA XS Series Combustion Air And Venting Components, Axial Fan, Control System

2.5 COMBUSTION AIR AND VENTING COMPONENTS

A.Vent Box: The vent box shall be of [aluminized steel] [409 stainless steel].

B.Flue Fan: Each unit shall have a factory-installed flue fan to draw combustion gases through the heat exchanger and into the flue venting. No unit shall be gravity vented. The flue fan shall be internally mounted by the manufacturer. No combustion draft inducers shall be mounted outside of heater cabinet.

C.Combustion Air: For non-separated units, the combustion air shall be drawn into the unit's exposed burner box directly from the heated space through openings in the access door. For separated units, the combustion air shall be drawn from outside the heated space into the unit's enclosed burner box through

a piece of flexible duct that terminates at an exterior cabinet flange. Ductwork shall be run from that flange to the building penetration.

D.Flue and Combustion Air Connections: The flue collar and combustion air collar (if applicable) shall be located on the rear of the unit. For Models 30 - 125, heater design shall allow for the shifting of the venting and combustion air collars to the top of the cabinet in the field.

2.6 AXIAL FAN

A.Fan: Each unit is supplied with one (Models 30-250) / two (Models 300-400) axial fan(s).

B.Fan Guard: Each axial fan is covered with a fan guard. The guard shall protect against objects ½" (12 mm) and greater in diameter.

C.Motor: The motor shall be an open drip-proof (ODP), standard efficiency design, wired for 120 V/ 1 Ø / 60 Hz. The motor shall be shaded pole (SP) (Models 30 - 75) / permanent split capacitor (PSC) (Models 100 - 400).

control terminal shall allow for 2-wire heating control or 4-wire heating and “fan only” control.

2.8OPTIONS AVAILABLE (Select Applicable Options)

A.Shelf-Mounting Bracket Kit (Available for Models 30-125 Only): The shelf-mounting bracket kit shall provide a manner in which to mount a unit to an existing shelf.

B.Wall Suspension Mounting Bracket Kit (Available for Models

30-125 Only): The wall suspension mounting bracket kit shall provide a wall-mounted structure from which a unit can be suspended.

C.Wall Shelf Mounting Bracket Kit (Available for Models 30-125 Only): The wall shelf mounting bracket kit shall provide a wall- mounted shelf structure on which a unit can be mounted.

D.Vertical Louver Kit (Available for Models 30-125 Only): The vertical louver kit shall provide a means to control horizontal air flow.

E.Concentric Vent Kit: The concentric vent kit allows the flue and combustion air to be consolidated into a single concentric vent, thereby minimizing the number of required wall/roof penetrations. The kit consists of a concentric vent box, a 4" (101 mm)vent terminal with baffle plate and a 6" (152 mm) (Models 30-250) / 8" (203 mm) (Models 300-400) combustion air terminal.

F.Fuel Conversion Kit: The fuel conversion kit allows for field-conversion of the type of gas supplied to the unit. The kit consists of a replacement spring for the gas valve and replacement orifices.

2.7 CONTROL SYSTEM

A.Factory Testing: The complete control system and burner and gas manifold functions shall be factory tested for proper operation and to simplify field commissioning.

B.Control Enclosure: Burner controls (transformer, ignition module, gas valve, safety switches) shall be internally mounted by the manufacturer. No burner controls or gas train components shall be mounted outside of heater cabinet.

C.Safety Controls:

1.Air Flow Switch: The air flow switch measures air pressure differential across the heat exchangers to verify blower operation and the presence of an adequate supply of combustion air. The gas valve cannot open until the air flow switch is satisfied.

2.High Temperature Limit Switch: The high temperature limit

switch shall turn the burners off when air is discharged above its set point. The switch ensures unit shut down in case of axial fan failure or any problem which may result in overheating.

D.Controls System: Units shall be equipped for use with 120 V / 1 Ø / 60 Hz power supply. All units shall be factory equipped with a 24 V thermostat control terminal strip on the outside of the cabinet, pre-wired to heater internal controls. Thermostat

2.9 PERFORMANCE

A. See Schedule on plans.