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Hope someone has an answer. I have a Lochinvar KBN 150 that was installed in 2007. The boiler locks out with error displayed as "high fan speed". The manual says to check vent blockage, wiring, replace fan and or replace control board. If I restart the boiler it will function properly. The lockout happens once the zones are satisfied and the boiler goes to standby. I notice the problem occurs more often when outside temps are higher, 40 degrees or more.
I do have an outside sensor. I have disconnected the sensor and get the same error.
The manual states the high fan speed error is displayed when fan exceeds 30% more then needed. When the boiler is operating the fan speed shows the fan running between 2000 and 5200 rpms depending on the firing rate. I have cleared the error codes, rest the boiler as well as de-energized the unit with hopes of clearing the board memory.
I hate to replace the wrong part since each part is about 500. Thanks in advance.