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This appliance uses a single cylindrical burner installed vertically into the cavity located in the center of the primary heat exchanger. There is a unique burner for each one of the three models.
Burners may NOT be changed between different Btu/hr input models. The burner consists of a round mounting flange welded to a mixing tube. The top side of the mixing tube provides the transition which mounts the discharge from the combustion air blower into the burner. The bottom side of the mixing tube is attached to a stainless steel perforated sleeve. This stainless steel sleeve is covered with a loose fitting, woven alloy material that forms the burner port surface. The woven burner port material is called Alcromesh which is a unique alloy of iron, chrome, aluminum and several rare earth metals. This alloy is designed to operate stress free as a burner port surface. The Alcromesh burner port surface can sustain operation from a blue flame down to infrared conditions as the burner input varies. Internally, the burner has a cone and distribution baffles to balance the air/gas mixture over the surface of the burner. The burner mounting flange provides a flame view port and the mounting point for the hot surface igniter. The hot surface igniter is removable from the burner mounting flange without removing the burner assembly from the heat exchanger.
NOTE:
An index mark is provided on the burner flange to ensure proper orientation when removing and reinstalling the burner. A properly indexed burner will ensure correct location of the combustion air blower and adequate clearances from other components in the top jacket chamber.
The burner is designed to operate from 100% of rated input down to 25% of rated input in normal operation. Burner operation at input rates of less than 50% may include operation in the infrared state. At input rates firing above 50%, there may be some slight infrared visible on the tips of the woven burner port material. This is normal burner operation.
COMBUSTION AIR BLOWER
This appliance uses a sealed air blower to provide combustion air for the burner and operate the Category IV venting system. The blower assembly consists of a sealed housing and blower wheel constructed from cast aluminum. The blower is operated by a fully enclosed 230 VAC, 3 Phase electric motor. This motor has a 3/4 HP rating on the 1,500,000 Btu/hr model and a 1 HP rating on the 1,700,000 and 2,000,000 Btu/hr models. The blower housing and motor assembly is fully sealed and CANNOT be field serviced.
ORIFICE |
MOUNTING |
TRANSITION |
CHAMBER |
FIG. 69 Combustion Air Blower and Transition Chamber
A sealed transition chamber is mounted on the inlet to the combustion air blower. This chamber contains the gas orifice and a sensing point for operation of the ratio gas valve. Inside the transition chamber, at the inlet to the combustion air blower there is a filter to prevent particulate matter and small foreign objects from entering the blower and burner. This filter should be checked and cleaned on a six month interval or more often in a contaminated environment. An inspection port is provided on the side of the transition chamber to allow access to the internal filter for inspection and cleaning. If cleaning is required, remove the filter through the inspection port and clean with soapy water or compressed air.
FIG. 68 Combustion Air Blower
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