Burnham 101008-01R1-2/07 manual Soft Lockout Codes Displayed, Code Condition Possible Causes

B.Trouble shooting problems where a soft lockout code is displayed. When a soft lockout occurs, the boiler will shut down and the display will alternate between the number “9” and the letter “b” followed by a two digit service code. The boiler will automatically restart once the condition that caused the lockout is corrected.

TABLE 14.3: SOFT LOCKOUT CODES DISPLAYED

CODE	CONDITION	POSSIBLE CAUSES
		• Blockage in intake or vent system.
		• Vent and/or intake system not constructed in accordance with Part VI.
b 08	Pressure switch circuit open	• Blocked or leaking pressure switch tubing
		• Heat exchanger or burner blockage
		• Terminals exposed to high winds
		• Blockage in condensate trap above vent.
		• Heating load at time of error was far below the minimum firing rate of the
	MCBA supply sensor detected temperatures in excess	boiler
b 18		• Defective primary pump or no flow in primary loop (Piping Method 1)
	of 200°F
		• Control system miswired so that boiler operation is permitted when no
		zones are calling
b 19	MCBA return sensor detected temperatures in excess	• See possible causes for “b18”
	of 200°F	• Flow through boiler reversed
		• Sensor wiring reversed
		• Flow through boiler reversed. Verify correct piping and pump orientation.
	MCBA is reading a return sensor temperature higher	• No boiler water flow. Verify that system is purged of air and that
b 24	than the supply sensor temperature. Condition must be	appropriate valves are open.
	present for at least 75s for this error code to appear.	• Sensor wiring reversed.
		• Supply or return sensor defective.
		• See possible causes for “b18”
b 25	Supply water temperature has risen too quickly	• Inadequate boiler water flow. Verify that pump is operating and that pump
		and piping are sized per Part VIII of this manual
b 26	Boiler safety limit, or external limit wired across	• See possible causes for “b18”
	terminals 3&4, is open.	• Defective supply sensor.
b 30	Temperature rise between supply and return is too high.	• Inadequate boiler water flow. Verify that pump is operating and that pump
		and piping are sized per Part VIII of this manual
		• Blockage in pressure switch hose
		• Pressure switch wires shorted together
b 61	Pressure switch circuit closed with fan off	• Defective pressure switch
		• Loose or miswired fan speed harness (if “b61” error code is observed
		while fan is running)
b 65	Fan is not achieving set point speed	• Loose or incorrect fan speed control connection
		• Defective fan

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