S4. Air Pressure
Profile plate sensing tubes should be checked quarterly and cleaned no less than semiannually. If the sensing tubes become even partially blocked, false pressure readings may be relayed. To clean, remove the screened end caps. Clean the screens and the tubes, if necessary. Re- place the cleaned end caps. Check the pressure differential across the profile plate using a slope gauge. Air pressure differential should be between
To attach the slope gauge, open the control compartment door panel. Just below the junction box, locate the tubing connections. Remove the cap at each connection and attach the slope gauge using two field- supplied 1/4" x 1/8" female NPT barbed tubing connections. For in- structions on measuring air pressure, see Service Section, Paragraph 9.
R5. Circuit Indicator Board (check lights)
The circuit indicator board is located in the control compartment elec- trical box (See Figure 7). Check operation of all indicator lights by switching lights that are not lit with one that is currently lit. Replace all burned out indicator bulbs (P/N 125189).
Figure 4 - Circuit | Row of Bulbs | |
Indicator Board, |
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P/N 151263 |
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Check bulbs not |
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lit with other |
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bulbs; replace |
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any burned out |
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bulbs |
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S6. Main Burner and Pilot Assembly
For the most part, the burner and pilot are self cleaning. However, if the application is extremely dirty or dusty, cleaning of the burner and pilot may be necessary. Inspect the burner annually. Follow these instruc- tions. If it is necessary to replace any parts, use only
1)Turn off the gas and power supply to the system.
2)Remove the door panels in the burner/control cabinet (four or six depending on whether or not the system has return air). Locate the pilot.
3)Disconnect the two ignition wires (male and female quick connec- tions) and disconnect the flame sensor lead at the burner. Remove the set screw located in the ignitor tube (set screw holds the brass bushing in place). Carefully remove the brass bushing and the igni- tor.
Check the hot surface ignitor for cracks or unusual deterioration. Check the flame rod for integrity. Replace the flame rod (P/N 131188) and/or the hot surface ignitor (P/N 121865) if not in good condition.
4)Clean the burner and pilot by
CAUTION: Wear eye protection while pressure cleaning and drilling.
Figure 5 - Burner
End Plate showing
Hot Surface Ignitor
Burner End Plate
Flame Sensor
Ignitor
If air pressure does not unplug burner orifices or pilot tube, drill burner orifices with a Size #50 drill and/or pilot tube with a Size #55 drill.
WARNING: Do not enlarge burner ports or performance may be drastically affected.
Inspect the upstream and downstream sides of the mixing plates. Remove any accumulation of scale or foreign material with a wire brush. If any mixing plate fasteners are loose or missing, tighten or replace. Always use zinc plated or stainless fasteners.
If any cracks are present, replace that mixing plate. Because of the effect of flame temperature on the metal, fasteners may be difficult to remove. Be careful not to damage the gaskets that go between the mixing plates and the burner body. The gaskets are designed to overlap approximately 1/16" for tight air seal.
5)Follow Steps in reverse order to
Figure 6 - Illustration of the first Burner Section
Mixing
Plate
Full length of the burner is made up of a series of 6" or 12" burner sections in a linear or oval configuration
Burner
WARNING: Burner profile plates are factory set to match CFM requirements.
Do not adjust profile plates without contacting your Sales Representative for technical assistance.
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