PENSOTTI PCH 34B H Cleaning Procedure page 21

Combustion Chamber Cleaning Procedure
15. Protect the refractory target wall by covering it with a piece of heavy duty plastic, such as a plastic container lid or the bottom of a 5
gallon pail cut to size. This will reduce the potential of damage caused by the cleaning brush or water spray.
16. Using a non-metallic brush, loosen the debris stuck to the surface of the heat exchanger tubes; pay particular attention to the area
between all the tubes. Remove the dislodged debris with the vacuum.
Especially in Between the Tubes
Protect the Refractory Brush to Loosen Suck Debris
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