Omnia Mechanical Group

571 Timpson Place Bronx, NY 10455

Phone: 212-534-2500

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Industrial Boiler Terminology for Property Owners and Managers

If you own or manage a rental property in New York City, there’s a good chance you use a commercial boiler for heat and hot water. And there’s a pretty good likelihood too that your boiler will need servicing unexpectedly sometime in the near future, even with regular upkeep. We put so much wear and tear on our boilers with our cold winters that a few issues are bound to come up now and then. When this happens, it’s very helpful to have a grasp of industrial boiler terminology so you can better describe the problem to experts, like the team at Calray Boilers.

Here’s a brief list of the most important boiler words and phrases you should know. You can learn even more if you observe and ask questions the next time your boiler is either undergoing routine maintenance or having one of those out-of-the-blue repair visits.

Industrial Boiler Terminology


This device signals the burner to operate or stop operating, depending on the temperature of the water in the boiler’s tank.

Automatic water feeder

The automatic water feeder supplies the boiler with fresh water when the tank level reaches a certain level. Use of automatic water feeder can be reduced by efficient steam return lines (see below) that reutilize condensate from radiators.


This is a barrier in the boiler that alters the flow of fluid, thereby creating turbulence that increases the heat transfer rate.

Boiler capacity

This is the pounds of steam a boiler is capable of producing, often expressed as BTUs or British thermal units (see below).

1,000 BTU = 1 lb. of steam
150 BTU = 1 sq. ft. of hot water
34.5 lbs. steam/hour = 1 boiler horsepower
1 boiler horsepower = 140 sq. ft. of steam radiation
240 BTU = 1 sq. ft. of steam
34,500 BTU = 1 boiler horsepower
1 gallon #2 oil = 140,000 BTU
1 cubic ft. LP gas = 2,550 BTU
1 cubic ft. natural gas = 1,000 BTU
1 kilowatt hour = 3,413 BTU
1 therm. natural gas = 100,000 BTU

Boiling point

This is the point where water changes to steam (aka a phase change). In the Fahrenheit system, this occurs at 212 degrees, which is equal to 100 degrees Celsius.

British thermal unit (BTU)

A BTU is a way of measuring energy. It is equal to the amount of energy needed to raise a pound of water one degree Fahrenheit (see table above).


This is an undesirable situation where bubbles are formed in a liquid when it falls below its vapor pressure. This alternate formation and collapse of vapor pockets can severely damage boiler components, especially pump impellers (the rotating blades that move liquid through the pump).

Check valve

Check valves are used where backflow in the boiler needs to be prevented, such as in the boiler feeder. They allow water to only flow in one direction.

Circulator pump

This pump propels water from the boiler to supply lines (see below), which bring it to kitchens, bathrooms, laundry rooms, and radiators.


When you burn a hydrocarbon (such as the natural gas that fuels most New York City boilers) with heat and excess oxygen, you have the process of combustion, used in boilers as well as in automobiles. Combustion takes place in the boiler’s firebox, sometimes also called the combustion chamber, which houses the burner.


Steam from heat radiators that has condensed (cooled) and become liquid water again is called condensate. This is often returned to the boiler to be warmed and used again, which makes the boiler more efficient and extends its lifespan.

Expansion tank

To prevent hazardous excess pressure, most boilers are equipped with an expansion tank that absorbs extra pressure from the main tank.

Exhaust stack

This is the collective term for your chimneys or flues that remove the unwanted (and sometimes dangerous) byproducts of boiler combustion, such as carbon monoxide, carbon dioxide, sulfur dioxide, and water vapor. These byproducts are also called flue gases.


This is fresh water sent to the boiler’s tank via the automatic water feeder (see above). A sensor in the automatic feeder detects when feedwater is needed based on main tank levels and activity from the steam return lines.


Gaskets are seals meant to stop leaks, primarily at joints. Because they are subjected to high heat, boiler gaskets are often made of steel. They supplement other types of seals and O-rings in the boiler system.

Hartford loop

The Hartford loop has been around for about 100 years. It helps equalize pressure of the steam pressure out of the boiler and the condensate coming back in.

Heat exchanger

Typically made of steel, copper, or cast iron, this is a vital element of the boiler where heat is transferred to water in the boiler tank to create hot water or steam.

Pressure reducing valve

This type of valve is required by law. It allows steam pressure to be released before it becomes dangerous to the boiler and those working around it.

Steam traps

Also known as steam return lines, steam traps are an important part of the condensate recovery system. They send condensate (see above) back to the boiler to be rewarmed, reducing the need for fresh water from the automatic feed and thereby helping the boiler run more efficiently.

Supply lines

Supply lines are distributor lines. They carry water from the boiler to any place it’s needed, including taps, appliances, and radiators.

Working pressure

This is your boiler’s normal operating pressure. We carefully calibrate this for both safety and boiler performance when we service boilers for our clients.

Do you need a checkup on your boiler or service for something that’s not running quite right? Don’t wait until you have a boiler emergency to get in touch. Call Calray Boilers today at 212-722-5506 or reach out online to schedule an appointment.

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 We may collect and store the following personal information:

  • Name, email, address, telephone number, and (depending on the service used), move-in dates;
  • Transactional information (such as lease terms, lease parties);
  • Computer sign-on data, statistics on page views, and traffic to and from the Website; and
  • Other information, including IP address and other web log information.

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 Antler Pump & Motor Corporation, 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 Antler Pump & Motor Corporation. 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: