Product Overview

60
Boiler Controls
McDonnell & Miller
O r dering Info r m a t i o n
• For low pressure steam and hot water boilers larger than
5,000 sq. ft. (465m
2
) capacity with cold water feed
• Quick-change replaceable cartridge valve and strainer
• Optional features
– No. 2 switch
– Manual reset
– Float block
• Proportional feed action
• Model 51 can be field upgraded with a No. 2 switch to
add low water cut-off function
• Maximum water supply pressure 150 psi (10.5 kg/cm
2
)
• Maximum inlet water temperature 120˚F (49˚C)
• Maximum vessel pressure 35 psi (2.5 kg/cm
2
)
Series 51
Series 51-2
Water Feeders – Mech a n i c a l
Series 51/51-2
Mechanical Water Feeders/Low Water Cut-Offs
Dimensions, in. (mm)
A B C D E F
NPT NPT NPT
1 8 (203) 1 0
3
⁄
8
( 2 6 4 ) 5
3
⁄
4
(146) 1
3
⁄
4
C a p a c i t i e s
Model Part Weight
Number Number Description lbs. (kg)
5 1 1 3 4 7 0 0 Mechanical water feeder 35.3 (16.0)
5 1 - B 1 3 4 8 0 0 51 w/float block 38.5 (17.5)
5 1 - B - 2 1 3 5 4 0 0 51-B w/Series 2 switch 38.3 (17.4)
5 1 - B - 2 - M 1 3 5 5 0 0 51-B-2 w/manual reset 38.3 (17.4)
5 1 - 2 1 3 5 0 0 0 51 w/Series 2 switch 35.8 (16.2)
5 1 - 2 - M 1 3 5 2 0 0 51-2 w/manual reset 35.7 (16.2)
Electrical Ratings
Motor Switch Rating (Amperes)
Voltage Full Load Locked Rotor Pilot Duty
120 VAC 10.2 61.2
125 VA at
240 VAC 5.1 30.6
120 or 240 VAC
60 Hz
06. HotWtrLwco 50-61• 3/6/07 12:44 PM Page 60