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Models 51, 51-S and 53 Boiler
Water Feeders
Models 51-2, 51-S-2 and 53-2
Feeder Cut-Off Combinations
OPERATION
Maximum Water Supply Pressure
Models 51/51-2 and 53/53-2: 150 psi (10.5 kg/cm
Models 51-S/51-S-2: 100 psi (7 kg/cm
Maximum Boiler Pressure
Models 51/51-2 and 51-S/51-S-2: 35 psi (2.5 kg/cm
Models 53/53-2: 75 psi (5.3 kg/cm
Electrical Ratings
Motor Switch Rating (Amperes)
Voltage
Full Load
120 VAC
10.2
240 VAC
5.1
• Before using this product read and understand instructions.
• Save these instructions for future reference.
• All work must be performed by qualified personnel trained in the proper application, instal-
lation, and maintenance of plumbing, steam, and electrical equipment and/or systems in
accordance with all applicable codes and ordinances.
• To prevent serious burns, the boiler must be cooled to 80˚F (27˚C) and the pressure must be
0 psi (0 bar) before servicing.
• 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.
• We recommend that 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 be connected in series with the burner control
circuit to provide safety redundancy protection should the boiler experience a low water
condition. Moreover, at each annual outage, the low water cut-offs should be dismantled,
inspected, cleaned, and checked for proper calibration and performance.
• 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.
• To prevent a fire, do not use this low water cut-off to switch currents over 10.2A, 1/2 Hp at
120 VAC or 5.1A, 1/2 Hp at 240 VAC, unless a starter or relay is used in conjunction with it.
Failure to follow this warning could cause property damage, personal injury or death.
2
)
2
)
Locked Rotor
Pilot Duty
61.2
125 VA at
120 or 240 VAC
30.6
McDonnell & Miller
Installation & Maintenance
®
2
)
Series 51
2
)
Series 51-2
WARNING
!
Instructions
MM-315(C)
Series 51-S/53
Series 51-S-2/53-2
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Summary of Contents for ITT 51
- Page 1 Water Feeders Models 51-2, 51-S-2 and 53-2 Feeder Cut-Off Combinations OPERATION Maximum Water Supply Pressure Models 51/51-2 and 53/53-2: 150 psi (10.5 kg/cm Series 51 Series 51-S/53 Models 51-S/51-S-2: 100 psi (7 kg/cm Maximum Boiler Pressure Models 51/51-2 and 51-S/51-S-2: 35 psi (2.5 kg/cm Models 53/53-2: 75 psi (5.3 kg/cm...
- Page 2 INSTALLATION – Models 51 / 51-2, Models 51-S / 51-S-2 and Models 53 / 53-2 – For Steam Boilers with 1” (25mm) Equalizing Lines TOOLS NEEDED: One (1) flathead screwdriver and two (2) pipe wrenches. STEP 1 - Determine the Location of the Feeder and/or Low Water Cut-Off Determine which situation applies: a.
- Page 3 Test the Model 51/51-2, 51-S/51-S-2 and 53/53-2 Before Turning it Over to the Owner Open the blow-down valve while burner is operating. As the water level drops the feeder will begin to add water. As the water continues to drop the burner will shut off (on the 51-2, 51-S-2 and 53-2 only).
- Page 4 INSTRUCTIONS FOR PIPING THE WATER FEEDER VALVE Models 51 / 51-2, Models 51-S / 51-S-2 and Models 53 / 53-2 For Steam or Hot Water Boilers TOOLS NEEDED: Two (2) pipe wrenches. STEP 1 - Piping the Valve on Models 51/51-2 a.
- Page 5 ELECTRICAL WIRING Models 51-2, 51-S-2 and 53-2 TOOLS NEEDED: One (1) flathead screwdriver. WARNING • 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.
- Page 6 • If no water leaks from the union, the feeder operation TO BOILER is not the cause of the flooding. Series 51 Removal of cartridge and strainer for inspection and cleaning A. Using a 1/2" socket wrench, unscrew the four (4) hex-head bolts (B) that secure the strainer basket (H) to the valve assembly (E).
- Page 7 Solution: Clean or replace piping. Test: Perform broken union test. With union broken, f) Cause: City water supply is above 150 psi (51, 53 there should be water flowing through the piping from Feeders) or 100 psi (51-S Feeder).
- Page 8 Replace if screen is torn or not able to be cleaned. required or in applications with high make-up water • Remove and inspect/clean cartridge. (For Series 51 requirements. Feeders Only). Replace if poppet does not move freely or debris cannot be removed.
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