Crown Boiler BWC151 manual Soft Lockout Codes Displayed

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 VII.
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 boiler.
b 18	MCBA supply sensor detected temperatures in excess	• Defective primary pump or no flow in primary loop (Piping
	of 200°F.	Method 1).
		• Control system miswired so that boiler operation is
		permitted when no zones are calling.
b 19	MCBA return sensor detected temperatures in excess of	• See possible causes for “b18”.
	200°F.	• Flow through boiler reversed.
		• Sensor wiring reversed.
		• Flow through boiler reversed. Verify correct piping and
	MCBA is reading a return sensor temperature higher	pump orientation.
		• No boiler water flow. Verify that system is purged of air
b 24	than the supply sensor temperature. Condition must be
		and that 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 IX
		of this manual.
b 26	Boiler safety limit, or external limit wired across terminals	• See possible causes for “b18”.
	3&4, is open.	• Defective supply sensor.
		• Inadequate boiler water flow. Verify that pump is
b 30	Temperature rise between supply and return is too high.	operating and that pump and piping are sized per Part IX
		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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