Mobile, trailer-mounted rental boilers were designed to provide a time-efficient solution that allows facilities to avoid downtime and lost production. More than 50 years ago, the first package watertube boiler mounted on a highway-legal trailer produced just 20,000 lbs./hr. of saturated steam. Today, rental boilers are offered in a variety of sizes, with some of the world’s largest trailer-mounted, mobile rental boilers providing up to 125,000 lbs./hr. of saturated steam production and 110,000 lbs./hr. of superheated steam production. 

A rental boiler can be utilized for several different reasons, including increased steam requirements, peak/seasonal demand, planned maintenance, equipment retrofits, research and development projects, or emergency repairs. While rental boilers supply the additional steam production often lost in these scenarios, there are other options also offered on a temporary rental basis for most equipment found in the boiler room. Knowing what is available and preparing in advance can help ensure a successful rental project. 


Understanding Your Plant’s Needs

When planning for a temporary boiler rental, the first and foremost step is knowing your unique plant requirements. How much steam is required to fulfill your production demand? Steam capacity is often conveyed in pounds-per-hour (lbs./hr. or pph) or in horsepower (hp). Operating pressure, steam temperature, fuel source, water source, and electrical supply are additional factors that will need to be known prior to locating a rental boiler. 

Facility personnel must determine a good location to spot and install the temporary rental equipment. Ideally, this would be a location with easy access to all required utility connections (water, fuel, and power). The foundation must be able to support the weight of the boiler equipment, and the location must be accessible by large semitrailers and flatbed trucks that typically transport these mobile boilers and related rental equipment. If the location is outdoors and in a region with inclement weather, freeze protection must also be considered. 

Lastly, emission limits vary based on local guidelines deemed by the state, county, or internal protocols, and these requirements must be known and communicated in advance. Ultra-low NOX rental boilers, temporary electric boilers, and selective catalytic reduction (SCR) rental systems are available to meet any stringent NOX and CO requirements. The rental equipment supplier can often help with identifying the best option available as well as aid throughout the permit process.


Typical Rental Boilers Available

There is not a “one size fits all” solution in the boiler industry, which is why rental boilers are built in a variety of types, sizes, and designs to meet the needs of many commercial and industrial facilities. The four types of rental boilers commonly found on the market today are as follows: 

  1. Trailer-mounted firetube and watertube boilers; 
  2. Skid-mounted firetube and watertube boilers; 
  3. Trailer-enclosed firetube boilers; and
  4. Complete mobile steam plants – enclosed and open-trailer systems.

Generally speaking, firetube rental boilers range in size from 50-1,000 hp, while watertube rental boilers are offered in larger capacities up to 250,000 lbs./hr. For larger steam demands that may not be possible with just one rental boiler, units can be rented and installed in parallel. 

A boiler-only option is often all that is required for a temporary steam need, as long as existing auxiliaries are available for use with the rental boiler; however, a complete mobile boiler room/mobile steam plant includes all auxiliaries necessary to produce steam and is a good option when existing auxiliary equipment is not available for use with the rental boiler. 

The largest mobile boiler room available today is 1,000 hp. Typically, a mobile boiler room or mobile steam plant will include the boiler/burner package, a feedwater system or deaerator, a duplex or triplex water softener, blowdown separator, and motor control panel. All equipment is pre-piped and wired for a convenient, packaged rental solution.


Additional Rental Options

Other rental options are available to fulfill voids in the boiler room when additional requirements need to be met or if other equipment goes down for maintenance, is being replaced, or unexpectedly fails. This includes:

  1. Water treatment equipment, such as deaerators, feedwater systems, water softeners, and complete feedwater vans;
  2. Equipment for increased efficiency, like economizers and blowdown heat recovery systems;
  3. Equipment for emissions control and reporting, like SCR systems, DataStak™ emissions and efficiency monitoring systems, and continuous emissions monitoring systems (CEMS); and
  4. Other equipment including blowdown separators, gas regulators, plant master control panels, gas flow meters, extra steam header valves, custom boiler stack, and spare parts packages.

Furthermore, the majority of industrial boiler systems require a qualified operator to properly operate and maintain the rental equipment for the duration of the project. Some rental companies offer qualified boiler operators as an extension of their equipment offering. This provides peace of mind when facilities do not have their own personnel available to maintain the rental equipment. 


Preventive Maintenance and Water Treatment

It is important to know that preventive maintenance and proper water treatment is vital to the life of a boiler system, whether a temporary unit or permanent installation. While the equipment supplier is expected to provide a unit that has been properly serviced and free of defects, the user has responsibilities as well. 

To ensure safe, continuous, and trouble-free performance, facility personnel must perform daily checks, and routine maintenance must take place during normal operation of any rental equipment. This includes inspection of all safety devices and low-water cutoffs during each shift as well as feedwater treatment and blowdown services. 

The use of boiler water treatment chemicals is imperative, and a reputable water treatment company should be involved in the process early on. Failure to maintain proper water chemistry is a major cause of rental boiler damage and the single biggest rehabilitation expense.    



Increased profitability is a major goal for any sound business operation and a proven way to increase profits is by avoiding downtime and lost production. Renting a boiler will help keep production moving and profits high, saving companies hundreds of thousands of dollars that would typically be allocated to lost production. 

Whether it is a short-term need or long-term steam requirement, temporary boiler equipment can save time, conserve capital, minimize risk, and maximize available resources.