Xylem MM 283D Guard Dog Series 751P and Series 752P Probe Type Low Water Cut-Off - Manual (Page 7)

STEP 6 - Testing and Diagnostic Procedures
Series 750 LWCO with Green Power On LED and Red Low Water LED
Start-Up
turn on the electric power to the boiler. a. Before filling the system,
1. Upon initial power up, the Green and Red lights will flash
simultaneously 4 times.
2. The Green light will turn "ON".
3. Red LED will be flashing for 30 sec. and turn solid on afterward.
4. The burner will never turn "ON" during power up, if water is off
the probe.
b. Now fill the boiler with water.
(When water returns to the probe, nothing will happen until the manual reset button is depressed.)
1. After depressing manual reset button, the Green and Red lights will flash simultaneously 4 times.
2. Then the Green light will turn "ON" and the Red light will turn "OFF".
3. The burner will be "ON" as long as there is water on the probe.
Manually Testing Control
c. Slowly drain the boiler of water.
1. When the water drops off the probe, the Green light remains "ON".
2. The Red light starts flashing and the burner will turn "OFF", if water is off the probe.
Red LED will turn "OFF" and burner turns "ON" if water returns to probe during 30 sec.
Testing Control Using "Test Button"
d. Depressing the test button with "water on probe." :
(Must depress and hold test button for 30 sec. to activate test cycle, Red LED will flash and Green is "ON".)
1.B oth Red and Green LEDs stay "ON" after test cycle is activated.
2. The burner will turn "OFF".
(Release test button. You must depress the manual reset button to unlock the low water cut-off.)
3. Then the Green light will turn "ON" and the Red light will turn "OFF", after Red and Green lights flash
4. The burner will turn "ON" as long as there is water on the probe.
CSD-1 Compliance
On Manual Reset Units, if the control is in low water condition (water is off the probe) and there is a sudden
Red LED will turn "ON" burner turns "OFF" if water below probe.
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simultaneously 4 times.
power interruption, the control will remain in low water condition (B urner Off) even if the power is restored.
The Reset B utton must be depressed to mak e the control back to function, after the water level is re-established
to the probe.