Product Overview

ITT
8200 N. Austin Ave.
Morton Grove, IL 60053
Phone [phone]
Facsimile [phone]
www.mcdonnellmiller.com
Boiler Controls
McDonnell & Miller
Low Water Cut-Offs – Electronic
For Hot Water and Steam Boilers
Series 751P/752P
•For commercial or industrial applications
•Primary or secondary control on hot water boilers
• Secondary control (manual reset models only) on
steam boilers
•Manual reset models meet the requirements of
ASME Standard CSD-1. If the control is in a low
water condition when there is an interruption of power,
the control will remain in a low water condition when
power is restored. The reset button will need to be
pressed when the water level is restored to a level
above the probe to allow the burner to fire.
Standard Features
•Green power in on indicating LED
• Red low water indicating LED
•Test button
• No lock out with loss of power if probe is in water
• 20,000 ohms sensitivity
Series 751P/752P
Ordering Information
Model Part Weight
Number Number Description lbs. (kg)
752P-MT-24 176296 LWCO - 24V w/standard probe 2.5 (1.1)
752P-MT-U-24 176298 LWCO - 24V w/ext. barrel probe (‘U’) 2.5 (1.1)
752P-MT-SP-24 176297 LWCO - 24V w/short probe (‘SP’) 2.5 (1.1)
751P-MT-120 176234 LWCO - 120V w/standard probe 2.5 (1.1)
751P-MT-U-120 176214 LWCO - 120V w/ext. barrel probe (‘U’) 2.5 (1.1)
751P-MT-SP-120 176295 LWCO - 120V w/short probe (‘SP’) 2.5 (1.1)
A
B
C
D
E
F
G
Electrical Ratings
Model
752P-MT-24
752P-MT-U-24
752P-MT-SP-24
751P-MT-120
751P-MT-U-120
751P-MT-SP-120
AB CD EFG
Std. SP UAll U NPT
6
3
⁄8 (162) 5
1
⁄8 (130) 2
9
⁄16 (65) 1
9
⁄16 (40) 3
1
⁄16 (78) 3
1
⁄16 (78) 3
1
⁄16 (78) 2
1
⁄8 (54)
3
⁄4
3
⁄4 (20)
Dimensions, in. (mm)
Control Unit
Temperature Ratings:
Storage: -40˚F to 135˚F (-40˚C to 57˚C)
Ambient: 32˚F to 135˚F (0˚C to 57˚C)
Humidity: 85% (non-condensing)
Electrical Enclosure Rating: NEMA 1 General Purpose
Hz: 50/60
Control Power Consumption: 3 VA (max.)
Maximum Steam Pressure: 15 psi (1.0 kg/cm
2
)
Maximum Water Pressure: 160 psi (11.2 kg/cm
2
)
Maximum Water Temperature: 250˚F (121˚C)
Probe Specifications
Control
Voltage
24VAC
120VAC
Switch Contact Rating
(Pilot Duty)
50VA@24VAC
Or
125VA@120VAC