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Background: In the past, using anti siphon valves between the day tank and a generator has been discouraged due to the low vacuum capability of generator pumps. A generator fuel oil pump may only be able to pull 5 in. Hg. In addition, there is a filter installed between the day tank and the generator pump that takes a 2-3” Hg pressure drop. This means that only 2” Hg could be available to open an anti-siphon valve, which poses a problem for most designs. Engineers have addressed the need to prevent siphoning from a day tank by installing a solenoid valve that opens when the generator pump turns on. However, this solenoid needs to be wired and is dependent on the controls functioning properly.

Solution: Now, Preferred has a better solution! We now have an anti-siphon valve that will open with only 2” Hg of suction available, and it is designed for application between the day tank and the generator pump. In addition, this Low Vacuum Anti Siphon Valve is UL Listed. For diesel handling components, it is important to ensure the valves one is purchasing are listed by a an agency such as UL as it ensures compliance to a standard and that the product has been independently evaluated. This Low Vacuum Anti Siphon Valve is available in ½” up to 2” NPT.


Experts from Preferred Utilities help them identify their problem, and then get it solved.

The Block Island School in Rhode Island has been considering some major upgrades in 2019, and although they’ve hit a couple of snags along the way, Preferred Utilities Manufacturing was able to help them solve a heating oil problem that threatened to stymie their whole project.

Back in March, school staff discovered a troubling heating oil spill that needed addressing. The heating fuel spilled out of a vent pipe to the school’s roof and then onto the ground below, near the playground behind the school’s south wing.

In a recent article in the Block Island Times, Sam Bird (the town’s facilities manager) said that it was not an easy diagnosis. The culprit, he and the representatives from Preferred realized, was a check valve in the fuel supply piping that did not open to send the oil back to the main tank after an electronic control unit failed. 

“The valve had not opened, or had not had a reason to open, for years,” Bird said. With the valve stuck shut, the pump still going, and the return line closed off, the oil had nowhere else to go except out the roof vent. After a few minutes, the valve opened and the fuel flowed back to its tank, and no more oil spilled from the vent. To fix it, Preferred recommended that the school replace the electronic controls on the pumps and valves that supply fuel oil to the heating system. The new system will bypass the day tanks with new piping to create a closed system, preventing the same kind of spill from recurring

After the installation, Preferred will return to start the new fuel supply system and train town or school personnel to operate it.

In addition to addressing this fuel oil problem, the school’s operations staff also had the site tested for asbestos, and the results were negative. So they are good to go with their eagerly awaited renovation project!

Preferred is happy to have the opportunity to work with schools like the Block Island School to help them solve pressing issues in their physical plants. With winter weather looming, is your school or college looking at spending too much on heating?

Call us, and we’ll look for ways to increase your efficiency and save you money!


October is National Cyber Security Awareness Month. According to a study by the University of Maryland, there is a hacking attempt every 39 seconds. And, the average cost of a data breach in 2020 will exceed $150 million.

We live in a connected world. These connections allow for a pace of commerce and communication previously unimaginable.

As everything becomes more connected, threats to the cyber security of commercial facilities and industrial equipment grow every day.

Traditionally, when working with operationally sensitive equipment such as HMI/SCADA Systems, the established practice has been to “Air-Gap” your equipment and prevent any access from the outside world. Globalization, regulations, & advanced data analysis techniques have made this practice obsolete and costly to your bottom line. Plants that choose to be “Air-Gapped” lose out on new innovations that allow for increased oversight and efficiency optimization to plant systems.

Now, you can connect to your facility and equipment from anywhere without compromising the security of your operations.

The Preferred Cloud Remote Monitoring Platform offers three levels of encrypted, secure, and continuous analytics on your equipment, while recommending cost saving and preventative maintenance options to reduce downtime and emergency service.


Wondering how to reduce GHG emissions by 30% by 2025 or 80% by 2050?

If you’re thinking you need to completely retrofit your entire boiler room, you’re wrong. There’s more than one way to meet your goals AND stay within your budget.

Preferred’s FlexFit Controller Retrofit Package, is the easiest, least expensive, most efficient way to go linkageless. This controller adds O2 trim, draft control, VFD and valve-proving capabilities as a standard and helps you meet your emission reduction goals too!

See the NYSERDA funded study by Steven Winters Associates that recommends linkageless retrofits!

Bring some Combustion Joy home for your operators, custodians, and superintendents this Fall.


Join us for a presentation on engineering & designing fuel oil systems!

Thursday, September 26th, 3 PM EST.

Experts John Haber and Ed Twiss, PE, have over 30 years experience designing fuel oil systems in the greater New York City area, as well as complete knowledge of all NYC codes.

Register HERE!


By David Bohn

Read the article in Facilities Manager here!

Upgrading or replacing a boiler system presents one of the most daunting and expensive challenges a large facility can undertake. When the time comes—whether the current system is outdated and inefficient or it fails outright—facility management must take the time to fully understand the process in order to set facility management goals and make the right decisions to fulfill their energy and efficiency needs. Right now, a substantial number of colleges and universities, as well as more than 1,200 Veteran’s Administration medical center campuses across the country, are all undertaking system overhauls like this.

These system upgrades are driven primarily by environmental concerns. Most of the facilities will need to update their equipment, but some will require a full-system replacement. It’s a huge undertaking—but most administrators believe that the long-term savings will make the effort worthwhile.

Why make the change now?

One of the driving factors in getting this change implemented right away is regulatory. California, Texas, and New Jersey have implemented air quality standards that will not be met by older boiler systems. They must be upgraded or replaced.

These old systems often used technology that sacrificed environmental safety in favor of cost savings. Some systems incorporated metal mesh burners, which utilized filters that clog easily. The gradual clogging of air filters leads to less excess air, which leads to higher NOx emissions. NOx emissions are a combination of nitric oxide (NO) and oxygen. Nitric oxide is the result of fuel combustion and alone is not considered hazardous; however, combined with oxygen, it is the source of fog, acid rain, and ground level ozone, which has been linked to myriad health issues. And while some other systems might have utilized technology to reduce overall NOx, these systems had increased electricity costs.

A second reason for a system upgrade, therefore, is to address these cost concerns. Today’s upgrades do not require air filters, which used to add to operation costs. Upgraded systems also offer quick-change, dual-fuel capabilities, switching between gas and oil firing in less than three minutes. This saves on service costs, since multiple people are no longer needed to make the changeover. The greatest cost reduction, however, is in the demand for electricity. There is a reduction of up to 60 percent in electric consumption.

One way to realize a cost savings is by employing a system that allows one to adjust the output according to the demand. This adjustment is achieved via what is called the unit’s “boiler turndown ratio,” which is the ratio of the maximum heat output to the minimum heat output at which the boiler will operate both efficiently and controllably. As the desired temperature/pressure point is reached, the heat source is turned down, and if the temperature/pressure falls, the heat is turned up. In large campus applications, which require boilers to operate at a low proportion of their maximum output, a high turndown ratio is desired, and that can be achieved with modern upgrades. Traditional burners using fiber metal mesh provide a 3:1 turndown; however, with recent advancements in the field, there are now systems that can provide a 9:1 turndown or higher depending on NOx requirement. These systems can achieve ultra-low NOx emissions without the use of FGR (flue gas recirculation).

In addition to the cost savings realized through a 9:1 turndown, there is also the reduction in required maintenance. Not only are multiple people no longer needed for a dual-fuel changeover, but operating and monitoring the systems are also simplified. Older systems require constant maintenance to ensure fuel efficiency and emission control. For example, many older systems include jackshaft linkage. Due to the complexity of these systems, they require constant fine-tuning and maintenance by highly skilled operators. Maintenance of an upgraded or new system is far less complex.

Newer monitoring equipment also means fewer people are needed for hands-on examination of the system. Typically, with an older system, there was a boiler in each building—and that meant someone needed to be on location to monitor those systems. The ability to house the entire system in one location, or to upgrade the system to monitor from one location, results in lower maintenance costs.

Campuses making the changes

Higher education is becoming a competitive industry and honestly, who chooses a college or university because of how new the boiler equipment is? The utility plant is seen as a cost, and universities generally choose to invest in new buildings or facilities that will help them attract students. But with environmental awareness now a prominent part of the national discussion, universities are starting to see the value (both economic and otherwise) to going green. Here are a few examples:

A small, elite liberal arts college in Duchess County NY was working with old boilers that essentially could not fire. To fix the problem, they chose new burners that were compatible with their old boilers which saved them a great deal of money since they didn’t need to replace the whole system. They also replaced their vacuum condensate system for further modernization and efficiency. They are now planning to buy a second burner and are interested in a solution that burns liquid wood.

A prestigious medical school outside of Boston invested in new burners. Their solution provider helped them with reliable low life cycle cost/best value payback on their low pressure steam boilers by providing three 800 HP burners and a feedwater system. They burn natural gas with #2 oil as a back-up, and are actively considering carbon neutral fuels.

The campus heating plant main boiler suffered from several crippling issues at a large public college campus in upstate NY. Working with a vintage 600 HP steam boiler, the burner had a triplex nozzle system that was an issue from day one. The burner was low fire, disastrous and unrepeatable when cycled, and created uneven fires from the three nozzles that would not hold a tune-up. The nozzles constantly needed cleaning and adjusting. Only one person in the boiler room could keep it running for more than a week. They went with a proven installer who recommended a solution that holds a tune-up and remains stable with cycle repeatability in the lower firing ranges.

A medium sized Christian College in Providence RI was interested in going far beyond EPA requirements in order to reduce their emissions and maintain their electrical and combustion efficiency. They selected a solution to achieve the best of both worlds: 22pm NOx on two 900 HP burners with natural gas and #2 oil, with Burnermate Universal controls on both burners/boilers.

A very small private college in central MA was provided a 600 HP burner for an old boiler that was previously fired by a burner from a company that went out of business a few years ago. They also selected the Burnermate Universal controls. Before this, they had been shut down for a few years and faced an unreliable boiler plant. They chose the fuels that were readily available and may consider other options as they continue to invest in infrastructure.

VA Medical Center Case Study

VA Medical Center, Erie, Pennsylvania – Generally, systems that have been in service for 25 to 30 years would require replacement instead of an upgrade. Their system had been in place for three decades and required complete replacement. In order to make the most impact with this important project, they built an entirely new boiler plant from the ground up.

The engineering team at the V.A. determined that existing system had met its lifespan, and they wanted to replace with latest technology. Any short-term replacement would have simply been a Band-Aid. They realized, however, that a project of this magnitude would take time to do properly. The engineering team at the V.A. chose Greenland Enterprises, Inc. to handle the entire project based on their central plant expertise and track-record at other healthcare facilities.

Based on the campus steam load, they determined that the replacement equipment would consist of two 400-horsepower boilers and one 200-horsepower boiler. Installation of the new boiler system took four months. From the ground up (including the new construction), the work on the project took 14 months to complete.

This new plant will provide at least a 60 percent reduction in electricity consumption, which will be accomplished using a variable frequency drive. This technology can run with fan speed at a lower rate. For example, changing the power from 60hz to 30hz speed can cut the horsepower by eight times. Therefore, a 400-horsepower system would be cut to 60-horsepower. According to Steve Seckler, Vice President of Operations at Greenland Enterprises, “Most systems can go from 60hz to 40hz easily. We chose a system that can efficiently go all the way from 60hz to 15hz for additional savings.”

Fuel reduction provides cost savings over the life of the new system. Newer boiler systems can offer a savings of two to five percent. This means that one 400-horsepower boiler with a fuel cost of $500,000 annually can save between $10,000 and $25,000 a year. This new Erie plant, with its two 400-horsepower boilers and one 200-horsepower boiler, will save the hospital between $25,000 and $62,500 in fuel costs annually.

Is it time for an upgrade at your facility?

A boiler upgrade project like the one undertaken at the V.A. Erie Medical Center is clearly something that takes significant time and money to complete. But in the end, management determined that the expense and effort will pay off in the long run. Could it be time for you to look at a similar project for your facility? Here are some points to consider when making your decision.


In large facilities, sustainability can be neglected when considering boiler systems. Facilities like college campuses often rely on older boilers and choose the “Band-Aid” approach of patching and maintaining them out of necessity. This method is not sustainable. Upgrading to a new boiler is the best option for long-term, sustainable improvement.

Sustainability also refers to the environmental impact of a system. With ever-changing state requirements, it is important to choose a system with enough flexibility to face these new demands as well as future ones.


To sufficiently meet the heating and energy load demands of healthcare facilities, old boilers burn an inordinate amount of fuel. New boilers bring added efficiency and substantial fuel savings. There is also much being done in the realm of alternative fuels for boiler systems. Bio-fuels and liquid wood are two segments of the alternative fuel market that are making great strides.

Operation and Maintenance

New boilers are streamlined to operate more smoothly and efficiently than old boilers, which can be challenging to operate and maintain. The older boilers often take much longer to heat up, and they are often kept running to meet heating needs. New boilers are designed to heat up quickly and can be adjusted to handle variable loads to ensure less energy consumption.

When considering an upgrade or replacement, no matter what the reason may be, all factors of the operation need to be addressed in preparation for a system shut-down. A project of this magnitude, from the initial bid process to completion, will require a minimum of several months (for an upgrade) up to a year or more (for a complete boiler replacement). The impact of this change, and thus the importance of the decisions made during the process, are why so many campuses are carefully reviewing their future energy options.

David Bohn is President and CEO at Preferred Utilities Manufacturing Corporation, an engineering-based manufacturer of products for commercial, institutional, industrial and nuclear power facilities.


Read the article in Today’s Boiler

By David Bohn

If you can’t afford to replace your boiler system, new fuels and innovative technologies are the answer.

Fueling boilers has become more complicated. Many conventional fuels are now impractical because they can be dirty and expensive, and they are sometimes incompatible with modern environmental regulations. This creates a challenge since changing out an entire boiler system is a massive expense. Is it possible that your current system could work with new, environmentally friendly fuels?

The answer is yes, at least when it comes to these groundbreaking new fuel options.

The latest innovations in biofuel technology

Traditional biofuels such as wood chips or pellets, while preferable to non-renewable fossil fuels, have still been found to have a negative environmental impact that can be problematic in many applications. A relatively recent innovation in the sector involves replacing wood chips with a fuel known as “bio-oil” (also referred to as “liquid wood”). While this biofuel is more environmentally friendly, some users found it incompatible and difficult to use at first—but that is now changing. Boilers can be more easily modified to be compatible with liquid wood, and the cost is about one-tenth that of replacing the system.

Created by Ensyn Technologies Inc. out of Ontario Canada, liquid wood is produced using a thermochemical process called pyrolysis, in which wood is burned in excess of 500º C (in the absence of oxygen) and is transformed into a combustible liquid. Because there is no oxygen, the wood does not combust. It first becomes charcoal, and then further decomposes into gas and liquid. It behaves similarly to natural gas or crude oil except that it has much lower carbon emissions.

Liquid wood still has the advantage of being a renewable wood-based resource. The raw wood used to create liquid wood is harvested from tree farms—and more trees can continuously be planted to replace those used for fuel oil. Reducing dependence on fossil fuels and other non-sustainable sources is critical to reducing overall greenhouse gas emissions, and turning the raw wood into liquid wood fuel increases the environmental benefits even further.

An added advantage is that liquid wood is less cumbersome to store than wood chips or pellets. In order to utilize wood chips, the user must address two onerous tasks—turning the bulk wood into chips, and then storing the chips themselves until they are used. There is also the challenge of getting the wood chips or pellets to the burner as they are not often stored in the same location. The logistics involved in managing chipping and storage can lead to significant added costs, as Bates College in Maine discovered.

Bates recently overhauled their campus heating system. They weighed the idea of converting to wood chips, but they found that building a wood chipping plant and storing the wood chips on campus would have cost a startling $10 million upfront. When they realized they could achieve the same environmental benefits by converting to liquid wood instead of wood chips, while only spending $1 million on the conversion, the choice was easy. They implemented liquid wood as their primary heating source and saw their carbon footprint reduced by an astounding 83 percent.

What is Bio Residual™ oil?

One of the newest innovations in environmentally responsible fuel is bio-residual oil (BRO. This renewable energy source has 85 percent lower emissions that typical fossil fuels and has the potential to reduce carbon emissions in the United States by thousands of tons per year.

Made by Renewable Energy Group in Ames, Iowa, Bio Residual™ Oil is the biodiesel equivalent of No. 6 oil. It is made up of all the heavy hydrocarbons left over after the refining of biodiesel, which can be made from diverse biological materials such as agricultural waste, animal fats, and recycled cooking oil. BRO™ is too heavy and viscous to be burned in an engine, so Renewable Energy Group has been working with Preferred Utilities Manufacturing to test the capabilities of BRO as a boiler fuel.

Preferred’s engineers Chuck White and Dan Wallace have now adapted one of their burners to cleanly burn BRO.

Striking the balance between electrical consumption and NOx emissions

Although greenhouse gases are the chief focus of most sustainability goals, they are not the only emissions to consider. Industrial boilers also emit nitrogen oxide (NOx), which is a significant air pollutant and is the key component in smog. These NOx emissions are regulated by the EPA and state agencies, with standards becoming steadily tighter since the 1990s.

Unfortunately, decreasing NOx emissions means upping electrical usage—the lower the NOx, the more electricity required. This can be a source of concern for those looking at low-NOx burners. They face the tough choice of either getting a system with the lowest possible emissions while sacrificing significant electrical efficiency, or else using a higher emissions system (that might become obsolete in a few years if regulations continue to get stricter) in an attempt to save on electricity. This rock-and-a-hard-place dilemma is even tougher in states with high electrical costs such as Connecticut and Hawaii.

The solution lies in the flexibility afforded by a new generation of low-NOx burners with configurable emissions. These systems can be configured to meet current regulations or targets, while operating at the highest electrical efficiency possible. Should regulations ever change, the burner can easily be updated for the new target NOx levels.

The demand for fuels that will have minimal negative environmental impact and not contribute to harmful CO2 emissions is ever-growing for many reasons. Regulation of the industry is likely to continue and become more stringent, “green” methods are becoming more economically desirable, and, perhaps most importantly, manufacturers are actively seeking ways to use renewable resources because they believe it is the responsible thing to do. Innovations like liquid wood and BRO, as well as new configurable low-NOx burners, are helping customers to reach their renewable energy goals in ways that maximize positive results for their bottom line and for the environment.

David Bohn is president and CEO of Preferred Utilities Manufacturing Corporation.


-Luke Amory, Danbury, CT

Traditionally, when working with operationally sensitive equipment such as HMI/SCADA Systems, the established practice has been to “Air-Gap” your equipment and prevent any access from the outside world. Globalization, regulations, & the advent of AI have made this practice obsolete and costly to your bottom line. Plants that choose to be “Air-Gapped” lose out on new innovations that allow for increased oversight and efficiency optimization to plant systems. Thankfully there are options for advantageous plant engineers that want to access facilities remotely without compromising on security.

The simplest implementation of plant connectivity is accomplished by adding an Application-Aware Firewall. This device is often marketed under the moniker “Security Appliance” “SCADA Fuse” or “Secure Router”. A device such as this is would be used in a scenario where the plant network is expanded to access portions of the corporate LAN. The Firewall would sit between the corporate side and the plant side to monitor ingress and egress traffic and prevent unwanted communications by enforcing rules defined by the administrator. The flaw with this implementation is that by extending plant communications protocols outside of their normal bounds your plant becomes exposed to inherent vulnerabilities in these industrial communications protocols. Most industrial protocols were developed to be exclusively implemented in these “Air-Gapped” networks and therefore were optimized for ease of implementation and access. Lacking modern features such as encryption and mutual authentication, traffic from these protocols can be modified in transit or spoofed entirely. This creates a scenario where a party with malicious intent or “Bad Actor” on the corporate side of the network can potentially infiltrate the plant side of the network.

Alternatively, a more conservative solution to this problem is to implement what is called a protocol conversion gateway. This gateway, like a firewall, sits between the plant network and the corporate network, translating communications from each side with mappings configured by the administrator. This device allows the conversion of insecure plant protocols to be converted to more secure protocols such as BACnet or OPC-UA without exposing unsecured plant equipment to the corporate network. Unfortunately, the level of security provided by implementing a device such as this can very widely. Unless explicit specifications for a secure implementation is provided, the lowest bidder will not provide these security measures by default and forgoes these features in favor of simplicity of maintenance and configuration.

With the Preferred Cloud Platform, we have approached this problem from a different direction. The integrity of our and our customers’ networks is paramount and therefore we have designed a platform to facilitate that. From the beginning we have designed our systems to have security in mind at every step. So that even if there is a catastrophic failure in one part of our infrastructure the attacker has no means by which to proliferate their attack to our customers. By collecting data locally with our cloud gateway and ingesting data into our isolated and secured infrastructure we can provide all the benefits of a connected plant without creating an attack vector from your corporate network or burdening your team with complicated security configurations. Preferred also leverages this connectivity to supply operations teams with tools that enable you to be more aware of problems with your equipment and to assist you in optimizing your plants for peak efficiency.

View the Preferred Cloud Platform here!


We have reason to celebrate! Preferred successfully completed the UL testing of our 1200 HP Ultra-Low NOx Ranger burner at Johnston Boiler. We now have UL listing on the following:
API-AF : 50 HP through 600 HP
API-RF: 100 HP through 1200 HP Ranger-RF: 100 HP through 1200 HP
We also have ULB listings on the entire range of: API-AF, API-RF, and Ranger-RF.

UL LIsting is required to sell burners into New York City and to put together a UL listed boiler package.