Omnia Mechanical Group

571 Timpson Place Bronx, NY 10455

Phone: 212-534-2500

Contact us on email!

The More You Know: What Is a Low Water Cut Off And Why Is It Critical for Your Boiler?

If you provide heat and hot water as a landlord for a New York City property, you likely have a low water cut off for the boiler as part of your system. This is an essential element, but it often goes overlooked until there are problems with it. Here is some vital information about your boiler low water cut off valve and how you can keep it functioning properly.

What Is a Low Water Cut Off?

Safety for your boiler

Low water in a boiler refers to any level that the manufacturer has deemed unsafe for operation. If a boiler continues to run without adequate water, eventually, there will only be steam in the system. As a result, the metal tank can overheat and fail.

Therefore, many boilers are outfitted with a low water cut off valve (sometimes abbreviated LWCO). These devices have been around since the 1920s, although the technology has improved considerably in recent decades.

A mechanical float or electronic sensor monitors the amount of water in the tank (see below). If the water level reaches dangerously low levels, the low water cut off valve shuts off the heat source for the system. Continuing to operate without sufficient water levels is known as “dry firing” and should be avoided at all costs. With few exceptions, a dry fired boiler will need to be immediately replaced.

What’s the Difference Between the Two Types of LWCOs?

Float-type or mechanical device

This type of device is used in a variety of different boilers, including those in residential, commercial, and institutional buildings. You might compare the older mechanical versions of this device to the float arm in a toilet tank.

A float is connected to an electrical switch, which, in turn, is tied to the boiler burner circuit. If the float drops due to a low water level, the circuit is broken, and the burner shuts off, cutting heat to the boiler.

Electronic sensor

With this type of device, an electrode tip remains immersed in the boiler tank to the desired level. If the electrode becomes dry due to the water being too low, it no longer conducts, cutting the circuit and stopping the heating process.

Is a Low Water Cut Off Required on Your Boiler?

NYC requirements

Because of the safety implications of running dry, low water cut offs are required by multiple entities. The New York City Construction Code states that:

“All steam and hot water boilers shall be protected with dual low water cut-off control.”

The only exception is boilers that only supply the individual dwelling unit in which they’re located, and they must have a total heat input of less than 350,000 Btu/h (1025 kW). These boilers are permitted to have only one low water cut off control, versus dual controls.

Other groups or publications that require low water cut off devices for boilers in their protocols include the American Society of Mechanical Engineers and the Internal Mechanical Code.

Do Low Water Cut Offs Malfunction?

Dangerous situation

Low water cut off valves do sometimes fail, which creates a high-risk situation, since this is a safety device. There are multiple factors that can cause a low water cut off to malfunction:

  • Condensates, hard water deposits, scale, mineral encrustation, etc.
  • Buildup of rust, dirt, or sediment
  • Poor maintenance, such as improper or lack of flushing
  • Aging, which can, in turn, result in worn parts, leaks, and shorts
  • Loss of water over time
  • Jumper wires left in place permanently after being used in tests to bypass circuits

Every year in the United States, there are thousands of accidents reported due to low water cut off control failure.

How Can You Keep Your Low Water Cut Off Working Properly?

Maintenance musts

Fortunately, low water cut off devices are typically not very complicated, which means that it’s largely within your control as a property owner or manager to keep yours working properly.

The first thing you can do as part of your own maintenance program is to check for obvious problems, such as:

  • Leaks
  • Buildup of undesirable materials
  • Corrosion
  • Electrical connection wear and tear
  • Breaker tripping repeatedly
  • Failure to activate when you know the water level is low

Second, older low water cut off valves or detectors should be replaced. If yours is nearing the end of its expected lifespan, it’s wise not to wait for it to fail before replacing it. Instead, be proactive, and arrange for the installation of a new device early. You’ll appreciate the peace of mind it gives you, and it’s well worth the cost.

If you have a float-type device, you want to make sure scale buildup on the inside wall of the tank doesn’t cause it to stick rather than floating free. You also want to check to see that it’s not waterlogged and sinking when it shouldn’t. One sign of this is the boiler cutting out even though the water level is fine. If you need assistance with these checks, we’re happy to do them for you, and they are part of our routine boiler maintenance program.

Electronic low water cut off devices can also fail due to scale buildup. The electrode may continue to “think” it’s in water when it’s not because it’s tricked by the mineral deposits. It can still conduct in many instances, so the system doesn’t shut off even when the water level drops to hazardously low levels.

Of course, thorough and professional maintenance of your boiler, including the low water cut off, is essential. We check everything with your low water cut off and perform proper flushing to get rid of anything that could cause malfunction.

If your boiler has not been looked over in a while, it’s time to call in the experts. You can reach Calray Boilers at 212-722-5506, or make an appointment using our online form. Don’t wait until you have a boiler emergency to call! Get in touch today.

Our Privacy Policy

Omnia Mechanical Group(the “Company”) strives to ensure the highest standards for property listings and customer information privacy. Please review the following statement to learn about our company practices and policies. Please be aware that our Privacy Policy is subject to change at any time.

1. Purpose.

This Privacy Policy (“the Policy”) provides information on how the Company uses your personal information. By agreeing to the Policy, you agree to our collection and use of your personal information as described in the Policy. This Privacy Policy is effective for all new users of

2. Personal Information.

You can browse some areas of (“the Website”) without being a registered user. However, certain activities do require registration. (You consent to the transfer and storage of your information by registering with

3. Use of Information.

Our primary purpose in collecting personal information is to provide you with a safe and user-friendly experience. For example, the Company may use your personal information to:

  • Improve our services and the Website’s content and layout;
  • Provide the services and necessary customer support you request;
  • Resolve disputes, collect fees, and troubleshoot problems;
  • Track and record customer satisfaction with our services;
  • Protect the Company against error and fraud;
  • Inform you of special promotions and announcements;
  • Enforce our agreements, terms, conditions, and policies; and
  • As otherwise described to you at the time of collection.

We may occasionally ask you to complete optional surveys. These surveys are used to improve and customize your experience with

The Company always provides you the ability to opt-out of further communication such as promotions and surveys; see the Opt-Out section below.

The Company does not share any of your personal information with outside organizations, companies, individuals, etc. The only exception to this standard is if such a disclosure is reasonably necessary to respond to any and all legal processes.

4. Links to Other Sites.

The Website may have links to other websites that may collect personally identifiable information about you. The Company is not responsible for the privacy practices of the content of those linked websites.

5. Safety & Security Precautions.

The Website has strict security measures in place to protect you and your information from fraud. Once your information is provided to Omnia Mechanical Group, we strive to ensure the confidentiality of your identity and information.

6. Opt-Out.

The Company provides you with the opportunity to opt-out of receiving promotional and other non-essential, marketing-related communications from Omnia Mechanical Group. If you would like to opt-out of these select communications, please see any of the Company’s email communications and follow the directions indicated.

7. Account Protection.

Your password ensures the security of your account. When choosing a password, the Company suggests using various characters. It is highly recommended that you do not disclose your password to anyone. (If you do disclose your password or your personal information with others, you are responsible for all actions taken in the name of your account.) If the security of your password is compromised for any reason, please contact the Company immediately.

8. Accuracy of Information

The Company does not guarantee the accuracy of information for any and all of its properties on the Website, and is not responsible for any errors or misrepresentations (made by Renters, the Client, or otherwise).

9. Cookies

The Company may place a small cookie on your computer’s hard drive. This allows us to personalize your use on the Website. In order to maximize the functionality and usability of the Website, you must set your browser’s preferences to allow both permanent and temporary cookies.

10. Changing Your Personal Information.

Should your personal information change, please immediately update your information on the Website. This will ensure the accuracy of our records. The Company does retain personal information from closed accounts in order to comply with law and collect and disburse any fees owed.

11. Third Parties

This Privacy Policy addresses only the use of information we collect from you. Since does not control the privacy policies of third parties, you are subject to the privacy policies of those third parties. It is advisable that you consult with the management of third parties before you disclose your personal information to others.

12. General

We may amend this Privacy Policy at any time by posting the amended terms on the Website. All amended terms are immediately effective after they are initially posted on the Website.

13. Privacy Policy Questions & Concerns

Questions and/or concerns regarding the Policy should be emailed to the following email address: