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11) Inspect the boiler and hydronic system for leaks.
12) Place the boiler back in operation using the procedure outlined in "Start-up". Check the pilot line and any other gas pip
ing disturbed during the inspection process for leaks.
SOOT DEPOSITS IN THE FLUE PASSAGES ARE A SIGN THAT THE BOILER MAY BE
OPERATING AT HIGH CARBON MONOXIDE (CO) LEVELS. AFTER CLEANING THE
BOILER OF SOOT DEPOSITS, CHECK THE CO LEVEL IN THE FLUE GAS TO INSURE
THAT THE BOILER IS OPERATING PROPERLY.
If it is necessary to check CO, use a combustion analyzer, or other instrument which is designed to measure
CO in flue gas. A CO "sniffer" designed for testing CO levels in ambient air cannot be used to check boiler com-
bustion. Take a flue gas sample by inserting a sample probe through the draft diverter opening and into the flue
collector so that the sample is taken in the area directly over the heat exchanger. Do not take a sample until
the boiler has been firing for at least five minutes. A normal CO reading for an AWR series boiler is less than
50ppm (0.005%). A reading of more than 100ppm (0.01%) is indicative of a combustion problem.
Some causes of excessive CO include:
•
Incorrectly sized main burner orifice for the altitude at which boiler is installed
•
Crooked or out-of-round orifice holes (never attempt to drill orifice for this boiler in the field)
•
Partially plugged flue passages
•
Improper manifold pressure
•
Foreign material in burner venturis or burner ports
•
Leak in seal between flue collector and heat exchanger
•
Inadequate supply of combustion air
1) Turn off electrical power and gas supply to the boiler.
2) Disconnect the damper and vent connector from the boiler.
3) Remove the top jacket panel. If possible, remove the rear and left side jacket panels
4) Remove the burners.
5) Disconnect the wiring at the blocked vent switch.
6) Remove the four #10 sheet metal screws holding the flue collector onto the block. Also remove the two #10 sheet metal
screws securing the flue collector to the rear jacket panel.
7) Remove the flue collector from the heat exchanger.
8) Carefully remove the flue collector gasket strips and set them aside.
9) Clean the flue passageways using a stiff bristle brush. Be certain that all foreign material is removed from the gaps
between the pins.
10) Clean the bottom surfaces of the heat exchanger.
11) Put a light in the combustion chamber and look through the flue passages from the top to verify that they have been
thoroughly cleaned.
12) Replace the flue collector gasket strips. If desired, RTV-732 silicone sealant with a 500F intermittent duty temperature
rating may be substituted for this rope gasket. The flue collector must be thoroughly sealed to the heat exchanger.
13) Reattach the flue collector.
14) Reattach all the jacket components.
15) Reinstall burners, being careful to put the pilot main burner in its original location.
16) Replace the blocked vent switch.
17) Reconnect the damper and vent system.
Heat Exchanger Cleaning Procedure
WARNING
37
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