When you rely on a boiler for heat in a commercial setting, the thought of replacing it and installing a new one can be stressful. There are the logistics of how the installation will impact businesses or residents in the building, the safety of the building during the installation, and concerns about how long the process will take. This post explores the timeline you can expect when installing a new boiler so you can plan accordingly and minimize the impact it will have on your building.
The Background: What Types of Boilers Are There?
The most common types of boilers used in commercial buildings are:
Fire-tube Boilers have a large chamber that contains hot gasses from burning fuel such as natural gas or oil. The hot gasses pass through tubes which are surrounded by water. The heat is transferred from the hot gasses to the water, and the resulting steam or hot water is used for heating. These boilers can be of the firebox-type or scotch marine constructions. Their efficiency can range from the low to mid 80% range. Using economizers, for both steam and water service, efficiency can be added to increase efficiency to the high 80s or low 90% range depending on the system.
Cast-Iron Boilers are built of cast-iron sections. Water is contained in the sections (one section is connected to the next by water passages). The lower portion of the assembled sections has a ‘furnace’ space where the combustion process takes place. The products of combustion then move up between the sections into another larger opening where they then exit at the back of the boiler. The heat transferred to the water can make hot water or low-pressure steam. Typical efficiencies for cast iron boilers range from the low to mid-80% range. Cast iron boilers have the unique advantage of being (reasonably) easy to assemble on-site, making them good candidates to get into a tight space – many mechanical contractors are familiar with assembling these types of boilers.
Water-tube Boilers have a series of tubes that contain water, which is heated by hot gasses from burning fuel. The heat is transferred from the hot gasses to the water, and the resulting steam or hot water is used for heating. Water-tube boilers’ efficiencies are around low 80% (steam) or mid-80% (hot water) range. Economizers, for both steam and water service, can be added to increase efficiency to the high 80s or low 90% range depending on the system. Similar to cast-iron boilers, some flexible-tube boilers can be field assembled, giving them good flexibility to get into existing rooms in a facility.
Electric Boilers use electricity to produce steam or hot water. They are typically smaller than fire-tube or water-tube boilers, so they can be used in buildings where space is limited. Electric boilers do not require a stack which means their location in the building is more flexible. However, there are limitations associated with electric boilers. While efficient (~99% wire to water), the cost of electricity is significantly higher than fossil fuels (Natural Gas or #2 oil) on a per-BTU basis. The building’s electrical system (and its power supply) must be able to support the electric boiler’s energy usage. If a building’s electrical system is not already designed for one, the cost of upgrading the system must be considered.
Condensing Boilers are designed to increase energy efficiency by recovering heat from the water content of flue gasses that are normally expelled through the stack. The water in the flue gas (produced as part of the combustion of Hydrogen containing fuels in the air) is in the form of steam. Reducing the flue gas temperature to below the dew point allows for the latent heat in the steam to be recovered as the water transitions back to a liquid state.
Steam versus Hot Water Boilers
All of the above – with the exception of condensing boilers – are available in steam or hot water configurations
- Steam Boilers: These boilers generate steam by heating water, which is then distributed through pipes to radiators or other heating devices. Steam boilers are commonly used in older buildings and industrial facilities. These typically have either low-pressure or high-pressure designs.
- Low-Pressure Designs have a pressure of 15PSIG
- High-Pressure Designs have pressures greater than 15 psig, typically up to 150PSIG (though higher pressures are available, these are not used for dedicated commercial comfort heating). Usually, for dedicated commercial comfort heating, steam boilers will be of the low-pressure type.
- Hot Water Boilers: These boilers are designed to produce hotter water for heating systems. They achieve this by raising the temperature of the water that circulates back from the heating system. There are three main types:
- Conventional Hot Water Boilers: These operate with design pressures equal to or less than 160PSIG and temperatures below 250oF.
- High-Temperature Hot Water Boilers: These work with design pressures exceeding 160PSIG and temperatures higher than 250oF. They are not typically used for standard commercial comfort heating but are instead suitable for larger facilities like campuses and district heating systems.
- Condensing Boilers: These boilers also have the same design pressure and temperature as conventional hot water boilers. However, they are optimized to work at lower temperatures, which increases their efficiency.
The choice of boiler type for a commercial building will depend on a variety of factors, including the size and heating requirements of the building, accessibility of the boiler room, the fuel source, your energy efficiency goals, and other factors.
How Long Does it Take to Install a New Boiler?
The time it takes to install a new boiler can vary depending on several factors, including the type of boiler being installed, the complexity of the installation, and the availability of parts and equipment. In general, direct replacement of a single boiler installation can take anywhere from a few days to a few weeks (or more) to complete.
This estimate does not include the procurement time of the boiler – this can vary from days to weeks, or months, depending on the type and size of the boiler and options chosen. In general, smaller condensing boilers have shorter lead times. Fire and Water Tube designs have longer lead times because these designs allow more customization which can increase production time.
For a straightforward boiler replacement, where the new boiler is being installed in the same location as the old one (direct-replacement), the installation process can typically be completed more quickly. However, if the installation is more complex, such as if new piping or ventilation or exhaust systems need to be installed, the process will take longer.
It’s important to note that the installation process may also be impacted by factors such as local building codes, weather conditions, and the availability of skilled labor.
Are There Other Steps to Be Aware of?
As mentioned above, the length of time it will take to install a new boiler will be impacted by what additional equipment needs to be installed or repaired. Most often, examples of this include new piping, or repair of existing system deficiencies if the building is old.
Additionally, adequate ventilation is a crucial part of the boiler installation and the safety of the boiler once it is functioning. There are code requirements that dictate the design of the combustion air intake system (whether directly communicated to the outside by louvers, ducted into a room, or other designs). These codes need to be reviewed and compared to the existing ventilation systems to make sure everything is up to code.
The combustion process in a boiler produces exhaust gasses that need to be vented to the outside of the building. Codes may dictate that an existing masonry chimney will need a stack liner installed to meet the code. Both the intake and exhaust systems should be reviewed and a plan created to address any deficiencies prior to starting work.
There are different types of ventilation systems that can be used with boilers, depending on the type and size of the boiler and the local building codes and regulations. For smaller residential boilers, a simple exhaust fan or a natural draft system may be sufficient to vent the exhaust gasses outside. In larger commercial or industrial boilers, mechanical ventilation systems (motorized louvers, draft fans in the stacks, etc.) may be required to ensure that the exhaust gasses are safely and efficiently removed from the building.
It’s important to follow the manufacturer’s instructions and local codes and regulations when installing and operating a boiler ventilation system to ensure the safety and efficiency of the system.
Downtime, Other Work, and Final Considerations
Will there be other work or upgrades to the boiler room at the same time? An example could be improvements to the electrical system, water heating system, etc. Any other trades will need to be coordinated with the boiler installations as they can impact the installation schedule.
Can your facility be down for any amount of time during the installation process? Do you have a single boiler or multiple? If multiple how are they sized? Are you planning the swap out for a time of year when the boiler is not needed?
If your facility has multiple boilers, it is possible to keep a boiler online while one is being replaced. It is also possible to do preparation work while the system is online to reduce the amount of downtime. If a review of the system determines that the boiler(s) will need to be offline during a time of year when heat is needed and for longer than the facility can tolerate, a rental boiler can be considered to provide temporary heat during the switchover.
Most of the above is written from the point of view of replacing an existing boiler. For a new installation, whether an existing building or a greenfield project, there are numerous additional considerations that will impact the amount of time needed to complete the installation of the boiler. Engineering review and approval, material procurement, other trade schedules, etc. will all come into play when determining the project’s schedule.
To get a more accurate estimate of how long it will take to install a new boiler in your specific situation, it’s best to consult with a professional boiler installation company. The professionals at W.C. Rouse & Son are more than happy to walk you through the installation process. Give us a call today!