Burnham FREEDOM 101008-01R1-2/07 Manual De Usuario

CODE

CONDITION

POSSIBLE CAUSES 

b 08

Pressure switch circuit open

• Blockage in intake or vent system. 
• Vent and/or intake system not constructed in accordance with Part VI. 
• Blocked or leaking pressure switch tubing 
• Heat exchanger or burner blockage 
• Terminals exposed to high winds
• Blockage in condensate trap above vent.

b 18

MCBA supply sensor detected temperatures in excess 
of 200°F

• Heating load at time of error was far below the minimum fi ring rate of the 

boiler

• Defective primary pump or no fl ow in primary loop (Piping 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 200°F
 

• See possible causes for “b18”
• Flow through boiler reversed
• Sensor wiring reversed

b 24

MCBA is reading a return sensor temperature higher 
than the supply sensor temperature. Condition must be 
present for at least 75s for this error code to appear. 

• Flow through boiler reversed. Verify correct piping and pump orientation.
• No boiler water fl ow. Verify that system is purged of air and that 

appropriate valves are open. 

• Sensor wiring reversed.
• Supply or return sensor defective. 

b 25

Supply water temperature has risen too quickly

• See possible causes for “b18”
• Inadequate boiler water fl ow. 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 
terminals 3&4, is open.

• See possible causes for “b18”
• Defective supply sensor.

b 30

Temperature rise between supply and return is too high.

• Inadequate boiler water fl ow. Verify that pump is operating and that pump 

and piping are sized per Part VIII of this manual 

b 61

Pressure switch circuit closed with fan off

• Blockage in pressure switch hose 
• Pressure switch wires shorted together
• 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

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.