McDonnell & Miller MM 286 Series 1575 Low Water Cut-Off - Manual (Page 8)

8
STEP 3 - Testing
Procedure
Turn on power to the boiler and pump circuits. With the boiler empty,
the control will be activated (Green LED On) and the pump should turn
on. The burner should stay off (Red LED On).
NOTE: If Green and Red LED’s flash alternately, the probes are out of
sequence, indicating they are not working correctly. Turn off power and
check probe wires for proper connection.
• Green light on: Unit has power
• Red light on: Boiler water dropped below the longest probe for longer than the adjustable time delay
setting. The burner has shut down.
• Red light flashing every second: Boiler water was below the middle probe for more than three
minutes and the burner has shut down.
• Auto reset units will automatically reset when the boiler water returns to the middle probe.
• Red light and green light flashing alternately every 1/2 second. Probes are out of sequence.
Unit has shut down. Unit will automatically reset when condition has cleared or been corrected.
• Red light and green light flashing simultaneously every 1/2 second: The PCB is too hot and the unit
has shut down. The unit will automatically restart when the PCB has cooled sufficiently.
• When using the “TEST” button, the green light will flash once per second during the time delay interval.
The time delay setting can be determined by counting the number of flashes.
Green Light – Shows status of shortest probe
Yellow Light – Shows status of middle probe
Red Light – Shows status of longest probe
• If the light is on, the probe is in water and probe resistance is well below the threshold.
• If the light is flashing every 1/2 second, the probe is in water, but probe resistance is near (just below)
the threshold.
• If the light is flashing every 2 seconds, the probe is out of water, but probe resistance is near (just above)
the threshold.
• If the light is off, the probe is out of water and probe resistance is well above the threshold.
I M P O RTA N T: Follow the boiler manufacturer’s start-up and operating instructions along with all applicable
codes and ordinances.
If the burner comes on, i m m e d i a t e ly turn the boiler off and make the
n e c e s s a ry corrections.
Failure to follow this warning could cause an explosion or fire and
result in property damage, personal injury or death.
WARNING
Exterior Lights
Interior Lights