4 FM quick reads on Boilers
1. Three common boiler safety devices
All boilers and domestic water heaters have a range of built-in devices to help ensure their safe operation. Like other components of building mechanical systems, they require periodic maintenance to ensure proper operation. Boiler operators and technicians should pay close attention to three key safety devices to protect personnel, equipment, and the facility:
- Safety valves. The safety valve is the most important safety device in a boiler or domestic hot-water system. It is designed to relieve internal pressure if a range of failures occurs within the system. Although it is simple in design and straightforward in operation, something as simple as corrosion or restricted flow within the valve and related piping can affect its operation.
- Water-level control and low-water fuel cutoff. Many systems combine these two separate boiler-safety functions into one unit. They are designed to ensure the water level within a boiler never falls below a predetermined amount. Should that situation occur, the system is designed to shut down the boiler by cutting off fuel. Proper functioning requires operators to make sure no build-up of sludge or scale exists within the system that would interfere with its detection and operation.
- Water-gauge glass. Even with a functioning water-level-control system, operators must verify the actual level of water in the system. Here, too, a build-up of sludge and scale can give false level indications.
2. Optimize Heating And Cooling Source Equipment To Increase HVAC Energy Efficiency
Today's tip from Building Operating Management comes from Daniel H. Nall of Flack + Kurtz. With the HVAC system's air and water distribution systems optimized, the heating and cooling source equipment can be optimized. There is a basic conflict between optimizing the efficiency of the distribution systems and optimizing the efficiency of the heating and cooling source equipment. For the distribution system, hotter hot water and colder chilled water can result in a greater temperature differential across the system, resulting in lower required flow and lower transport energy consumption. For the sources of heating and cooling, however, cooler hot water and warmer chilled water result in more energy-efficient production of these resources. Optimization of these conflicts will result in the most energy-efficient systems.
For both boilers and heat-pump-cycle heat sources, lower hot water temperature results in greater efficiency. Lower hot water temperature allows the utilization of condensing boilers and even lower hot water temperature increases the efficiency of the condensing boiler. Maximizing the efficiency of the entire system relies upon maximizing the thermal coupling between the distribution medium, air or water and the end use, the conditioned space. The key to optimal efficiency heating is thus close approach heating coils, or extended surface area convectors or radiant panels. By reducing the temperature differential between space and distribution medium (air or water), temperature differential across the transport system can be maximized while maintaining a lower-temperature heating source.
3. Factors to Consider When Choosing a Boiler and Water Heating Training Program
Just as there is a range of training formats available for boilers and water heaters, managers have options when it comes to program providers. Determining the most suitable provider for the facility depends on the manager's goals. For example, a number of different providers, such as those who conduct seminars or have online programs, can handle refresher training on the basics of boiler and water heater operations.
More specific training, such as would be required to learn the details of operating and maintaining an advanced boiler-control system, is often best handled by training representatives from the manufacturer.
Managers can start the selection process by getting a list of references from the prospective vendor or provider and talking with people who actually went through the training to better understand their experiences.
For each program being evaluated, managers must consider a number of factors. If the program is held at a remote location, what are the travel costs? Can people attend different sessions, or will all operators and maintenance personnel have to attend the same sessions? How often does the provider offer the program?
If the program is to be held in the facility, what does it cost to bring in the trainers? Does the facility have the necessary space and equipment? Can managers honestly expect operators and maintenance personnel to attend the sessions without interruption or being called away for an emergency?
4. In Boilers, Retrocommissioning Can Address Energy Inefficiency
Today's tip from Building Operating Management comes from James Piper, a contributing editor for Building Operating Management and Maintenance Solutions magazines: A retrocommissioning process can identify and address areas of energy inefficiency in boilers and water heaters.
The retrocommissioning process begins with a detailed review of the boiler or water heater, including data on equipment installed, connected loads, the critical nature of the loads, maintenance history, and operating performance.
Besides installation errors, operators might have made changes to the installation over the years. Of particular interest are changes they implemented to correct maintenance issues that are preventing the unit from operating as efficiently or effectively as intended.
Next, facility managers need to review maintenance records for the boiler and consider whether technicians have performed maintenance according to manufacturer recommendations or bypassed certain features to circumvent operational issues. They also need to determine whether the boiler has required more maintenance as it has aged, and they need to identify operational and maintenance issues.
Technicians need to check and test safety features to ensure proper operation. They also must measure the boiler's efficiency under different loads and verify the boiler's control system operates properly.
Once technicians have completed the test and managers have analyzed the results, managers will be able to identify the steps operators and technicians can take that will improve efficiency and performance. These steps can range from small changes in operating procedures to large overhauls of boiler components. Managers then will be able to estimate the cost and time needed to take these steps and evaluate their options.
The results of data-gathering and testing will be a road map managers can use to improve equipment operation. It will provide a list of recommended tasks, along with relative costs. Managers can implement some steps without interfering with the boiler's operation. Others will require careful scheduling because of the needed shutdown and interruption of service.
Retrocommissioning is not necessarily a one-time task. Facility managers must be ready to repeat the process to ensure the boiler or water heater continues to operate efficiently. The timing of the process will depend on the application, as well as the condition and size of the installation.
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