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We had a new boiler put in about four years ago. It is a Knight WB 105 attached to a very old hot water system. We have it serviced every season, but this year we received the "Fan Speed High" lockout. Our serviceman discussed the problem with the Lochinvar Rep. and recommended a controller board replacement. We did that to no avail, so the next step was the fan, so after we disassembled the front to replace the fan, we decided to clean the combustion chamber. It was piled with rust pellets. Not just a little. It was a huge pile.
Is this normal, or are we looking at a bigger problem?