Low Water Cut Offs (LWCO)

We stock a wide range of LWCO's for gas, oil and steam boiler applications from industry-leading brands, including Hydrolevel, McDonnel & Miller, Taco and others.
Available in low volt (24V) and line volt (120V), auto or manual reset options.
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3150 HydroStat, Temperature Limit & Low Water Cut-Off for Oil Boilers, 120V Hydrolevel
$159.95 / each
$611.80 box of 4
($152.95 each)
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3200-Plus Fuel Smart HydroStat, Temperature Limit, LWCO & Reset Control for Gas Boilers, 120V Hydrolevel
$182.95 / each
$707.80 box of 4
($176.95 each)
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3250-Plus Fuel Smart HydroStat, Temperature Limit, LWCO & Reset Control for Oil Boilers, 120V Hydrolevel
$165.95 / each
$643.80 box of 4
($160.95 each)
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Safgard 1100, Low Water Cut-Off w/ Auto Reset & Test Button, Gas, 24V Hydrolevel
$94.95 / each
$367.80 box of 4 + Free Shipping
($91.95 each)
LTR0243T-1, Low Water Cut-Off w/ Auto Reset & Test Button, 24V Taco
LTR0243T-1, Low Water Cut-Off w/ Auto Reset & Test Button, 24V
Part#: LTR0243T-1 Brand: Taco
Temporary Out of Stock
(2)
$120.95 / each
$467.80 box of 4
($116.95 each)
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Safgard 1100M, Low Water Cut-Off w/ Manual Reset & Test Button, 24V Hydrolevel
$114.95 / each
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RB-24SE GuardDog, Low Water Cut-Off w/ Auto Reset & Test Button, 24V McDonnell & Miller
RB-24SE GuardDog, Low Water Cut-Off w/ Auto Reset & Test Button, 24V
Part#: 144701 Brand: McDonnell & Miller
In Stock
$137.95 / each
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Safgard 1150, Low Water Cut-Off w/ Auto Reset & Test Button, Gas or Oil, 120V Hydrolevel
$94.95 / each
$367.80 box of 4 + Free Shipping
($91.95 each)
RB-122E GuardDog, Low Water Cut-Off w/ Auto Reset & Test Button, 120V McDonnell & Miller
RB-122E GuardDog, Low Water Cut-Off w/ Auto Reset & Test Button, 120V
Part#: 144703 Brand: McDonnell & Miller
In Stock
$136.95 / each
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Safgard 500, Low Water Cut-Off w/ Manual Reset & Test Button, 24V Hydrolevel
$178.95 / each
$695.80 box of 4
($173.95 each)
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Safgard 550, Low Water Cut-Off w/ Manual Reset & Test Button, Gas or Oil, 120V Hydrolevel
$181.95 / each
$707.80 box of 4
($176.95 each)
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Safgard 550SV, Low Water Cut-Off w/ Manual Reset & Test Button, Short Probe, Gas or Oil, 120V Hydrolevel
$178.95 / each
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Safgard 550P, Low Water Cut-Off w/ Manual Reset & Test Button, Long Probe, Gas or Oil, 120V Hydrolevel
$188.95 / each
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FPC-1000-P boilerwize, Universal Low Water Cut-Off, Standard Probe, Manual/Auto Reset & Test Button, 24V/120V McDonnell & Miller
$265.95 / each
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FPC-1000-U boilerwize, Universal Low Water Cut-Off, Extended Probe, Manual/Auto Reset & Test Button, 24V/120V McDonnell & Miller
$270.95 / each
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FPC-1000-SP boilerwize, Universal Low Water Cut-Off, Short Probe, Manual/Auto Reset & Test Button, 24V/120V McDonnell & Miller
$262.95 / each
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FPC-1000-RX2 boilerwize, Universal Low Water Cut-Off, Remote Probe, Manual/Auto Reset & Test Button, 24V/120V McDonnell & Miller
$280.95 / each
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Safgard 24SV, Low Water Cut-Off w/ Auto Reset, Short Probe, 24V Hydrolevel
Safgard 24SV, Low Water Cut-Off w/ Auto Reset, Short Probe, 24V
Part#: 45-245 Brand: Hydrolevel
Temporary Out of Stock
$100.95 / each
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Safgard 170, Low Water Cut-Off w/ Auto Reset, 120V Hydrolevel
Safgard 170, Low Water Cut-Off w/ Auto Reset, 120V
Part#: 45-170 Brand: Hydrolevel
In Stock
$102.95 / each
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Safgard 170SV Low Water Cut-Off w/ Auto Reset, Short Probe, 120V Hydrolevel
$102.95 / each
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Series 47-2, Mechanical Water Feeder & Low Water Cut-Off w/ Manual Reset McDonnell & Miller
Series 47-2, Mechanical Water Feeder & Low Water Cut-Off w/ Manual Reset
Part#: 132800 Brand: McDonnell & Miller
In Stock
(1)
$1,040.95 / each
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About Low Water Cut-Offs

Low water cut-off, frequently abbreviated as LWCO is an essential safety component of any boiler heating system. It's primary function is to cut off the power to the burner/heating element if the level of water inside the system is too low. This prevents dry-firing and consequent equipment failures and possible health and safety risks.

Frequantly Asked Questions

Q: What is the difference between manual and auto reset functionality on LWCO?
A: Manual reset controls require manual restart each time in a low water condition, meaning the reset button would have to be pressed to re-start the system once the water level is above the probe. Manual resets are most common for commercial applications and could be required by local code.

Q: What is the purpose of Test button on low water cut-off?
A: Test button allows to test the LWCO for functionality without manually lowering the water level.

Q: Why some LWCO's come with a standard probe, others with short or long? A: Since the probe must be in contact with system water to properly function, it is important so select the right size to ensure it freely contact water when its' level rises or falls. Most low water cut-off probes are standard, meaning they should universally fit majority of applications. Short probes may sometimes be used where LWCO is installed into a standard tee fitting instead of the boiler tapping.

Q: Where should low water cut-off be installed in the system?
A: In hot water boiler systems LWCO is commonly installed either directly in the boiler (if outside tapping is available), in the riser (vertical pipe leading to the boilers' fresh water supply/intake) or the header (horizontal pipe leading to the riser).
In steam systems, the LWCO is installed either in the boiler tapping or in an equalizing line. If used as a secondary (in steam systems), the control should be below the level or primary LWCO, but above the lowest permissible water level (specified by mfr).

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