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6

Circuit Board Layout

STEP 2 - Electrical Wiring

• To prevent electrical shock , turn off the electrical power before making electrical connections.

• This low water cut-off must be installed in series with all other limit and operating controls installed on the

boiler. After installation, check for proper operation of all of the limit and operating controls, before leaving
the site.

• Boiler manufacturer schematics should always be followed. In the event that the boiler manufacturer’s

schematic does not exist, or is not available from the boiler manufacturer, refer to the schematics provided
in this document.

Failure to follow this warning could cause electrical shock, an explosion and/or a fire, which could result in
property damage, personal injury or death.

WARNING

C over Removal and Installation Pro c e d u r e

a .

To remove cove r, use a flathead screw d ri ver to
loosen screws and remove the cover (K).

b .

To reconnect cove r, slide over bra ckets and tighten

s c r ews using a flathead screw d ri ve r.

c .

Following the appropriate wiring diagram (refer to
page 7) based on your application requirements,
and using BX armored cable or Thinwall electrical
metal tubing connector fittings, make electrical
connections to the junction box (L).

I M P O RTA N T:

There must be a minimum space

of 

2

" (13mm) between connector fittings and

electrical live metal parts.

K

L

BCOM

BNC

BNO

PCOM

PNC

PNO

N

H

BCOM

BNC

BNO

PCOM

PNC

PNO

N

H

60

30

Secs

.

0

60

30

Secs

.

0

BCOM

BNC

BNO

PCOM

PNC

PNO

N

H

0

60

30

Secs

.

0

Probe Connections

Bottom

Red

Middle

Yellow

Top

Blue

0-60 Second Adjustable
Burner Off Delay

110 Volt Input

from Boiler

Circuit

Manual Reset

(If applicable)

Low Water

LED

Red

Power

LED

Green

Test

Switch

Burner

Terminals

Pump

Terminals

BCOM

BNC

BNO

PCOM

PNC

PNO

N

H

Probe LED's

Summary of Contents for McDonnell & Miller 1575 Series

Page 1: ...secondary redundant Low Water cut off controls be installed on all steam boilers with heat input greater than 400 000 BTU hour or operating above 15 psi of steam pressure At least two controls should...

Page 2: ...ctivated turning the pump on after water drops below the middle probe If the water level is not restored to the top probe within 3 m i nutes the pump relay will be deactivated shutting off the pump Af...

Page 3: ...System Water Temperature 406 F 208 C Maximum System Water Pressure 250 psi 17 6 kg cm2 Maximum System Steam Pressure 250 psi 17 6 kg cm2 All probes in the Series 1575 units are sent from the factory p...

Page 4: ...l water level but not lower than the lowest safe permissible water level as determined by the boiler manufacturer OR If the control will be the secondary low water fuel cut off size the steam top and...

Page 5: ......

Page 6: ...over Removal and Installation Procedure a To remove cover use a flathead screwdriver to loosen screws and remove the cover K b To reconnect cover slide over brackets and tighten screws using a flathea...

Page 7: ...p Control Connect wire a from power supply to terminal H Connect wire b from neutral supply to terminal N Connect wire c from valve control circuit to terminal PNO Connect wire d from valve control ci...

Page 8: ...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...

Page 9: ...nit is factory set at 0 seconds To adjust turn the adjusting screw clockwise using a small flatblade screwdriver to the delay time desired Followthe bl owdown procedure found on page 11 to verify oper...

Page 10: ...pect probes The wiring connections for the pump may not be connected properly Check wiring at terminals Burner does not turn off when water level is below longest probe The probes may be fouled with d...

Page 11: ...ld be opened slowly The piping needs to be wa rmed up and stagant water in the drain piping needs to be pushed out Suddenly opening a blow down valve causes steam to condense which may create water ha...

Page 12: ...poses Seller warrants the goods purchased hereunder with the exception of membranes seals gaskets elastomer materials coatings and other wear parts or consumables all of which are not warranted except...

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