Omnia Mechanical Group

571 Timpson Place Bronx, NY 10455

Phone: 212-534-2500

Contact us on email!

Boiler 101: How Does a Boiler Work?

With nearly 80% of apartments in New York City still using steam heat, boilers are vital equipment for many properties. A boiler is a vessel that heats a fluid, usually water, to produce steam or heat for a property. It connects to a series of pipes that transport the steam or heated liquid through the building, with radiators, convectors, and underfloor systems dispersing the heat.

How does a boiler work to produce enough heat throughout your building? How can you ensure the system lasts its expected lifespan of 20-30 years? Discover everything to know about your boiler’s composition and operation.

How Does a Boiler Work? Understanding the Components and Process

Main Body

A boiler comprises many components, with the most important being the main body or pressure vessel. The pressure vessel is the closed container that holds the liquids or gases and pressurizes them, compensating for expansion and contraction in the system.

Boiler pressure can be dangerous if it gets too high. Modern boilers include pressure safety mechanisms and valves to avoid explosions and other safety hazards.

Other Components

In addition to the main body, boilers feature a number of other elements. The combustion chamber is where fuel or oil burns to warm the water supply. It contains burners and materials safe for volatile fuel and high-temperature operation.

The heat exchanger moves and heats water by transporting it around the heating element. Typically, the exchanger is a long, coiled pipe installed inside the boiler. Its primary job is to transfer heat from gases to liquids. Boiler efficiency depends on the exchanger’s ability to transfer and maintain heat.

A circulating pump is integral to the heating system and understanding how a boiler works. The pump creates suction from a header at the bottom of the boiler drum. The suction pulls the hot steam into the pump, where it gets pushed through the pipes to baseboard heaters or radiators. Simultaneously, the pump draws condensate back to the boiler for reheating.

Temperature controls keep the system balanced, allowing for fine-tuning of the combustion-to-steam-to-condensate cycle. It is best to leave boiler control adjustments to professionals because the wrong settings can interfere with the system’s efficiency.

Fuel is a significant aspect of boiler operation, affecting efficiency and operating costs. Depending on the age of your building, some fuel sources, like fossil fuels, are no longer permitted, although ongoing legal challenges may affect the new rules.


To understand how a boiler works, you must be aware of its primary processes: combustion, circulation, and distribution. Combustion in itself is a three-stage process involving preheating, ignition, and post-combustion. The preheating stage uses air preheaters or heat exchangers on the flue exhaust. The boiler becomes more efficient by preheating the combustion air, with approximately 1% improved efficiency for every 40°F increase.

The ignition stage occurs when the fuel source meets its ignition temperature — the temperature that causes more heat release during combustion than what’s necessary to sustain ignition. A mix of fuel, oxygen, and a heat source is essential for combustion to occur.

Post-combustion capture is necessary to separate carbon dioxide from exhaust gases produced when burning fossil fuels. Typically, the exhaust gases from the boiler travel through a CO2 absorber containing chemicals called amines, organic compounds derived from ammonia that bond to carbon.


Steam boilers use thermal circulation generated by pressure gradients produced by differential heating. The water in the boiler, being exposed to heat, turns into a mixture of liquid water and steam. Since steam is less dense than water, gravity pulls the water down, while the steam rises.

In a natural circulation boiler, water enters the economizer or heat exchanger and flows through its coiled pipe, entering the ring header and progressing up to where steam conversion takes place. The liquid water and steam continues rising until entering the boiler drum or vessel, where the liquid and gas forms separate.

Exactly how a boiler works with thermal circulation may vary depending on your building’s boiler. Other types of boilers use convection currents to circulate water.


The distribution process involves steam generation, movement, and return. Generation refers to the heating and vaporizing of water in the boiler (the combustion and circulation process). During generation, the boiler builds up pressure, allowing for increased thermal storage capacity, reduced risk of wet steam, and higher efficiency.

Once the system builds enough heat and steam, the heat pump cycles on, sucking the steam in and pushing it out to circulate through the building to points of use, typically radiators or baseboard heaters. The system can also tie into floor and radiant heating systems.

As the steam cycles through the property, it condenses back into liquid water. The condensate flows back to the boiler through returns. Once back in the boiler, it starts the cycle all over again.

How Do You Make Sure Your Boiler Works? Keeping It Operational


Knowing how a boiler works is more than theoretical knowledge; it has practical implications for a property owner. By understanding boiler operations, you are better equipped to recognize when something isn’t right or operations seem off. For example, you may notice sounds that differ from regular operation, like whistling, knocking, gurgling, or banging in pipes and radiators.

Knowing how your building’s boiler works can also provide insight into when to call for repairs, inspections, or maintenance. Noise is not the only reason to contact Calray Boilers. You should also call for:

  • Leaks
  • Radiator faults
  • Thermostat response issues
  • Pilot light failures
  • High energy bills

Regular Maintenance & Inspections

All boilers require annual inspections as well as regular maintenance. The recommended frequency of maintenance depends on the make and model, but an inspection should occur at least once a year between heating seasons.

How Does a Boiler Work and Remain Efficient? Expert Assessment and Timely Repairs

Hire Calray Boilers for All Repair and Inspection Needs

How a boiler works is a complex process, but now you have a general idea of this important appliance’s operation. Call Calray Boilers at 212-722-5506 if you are having trouble with your building’s boiler to schedule an inspection, maintenance, or repair.

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: