Temperature Controls
Temperature controls are devices that control the operating temperature of the boiler. Hot water boilers typically operate off of temperature. Some of these controllers are also safety devices that make sure that you do not go above a certain set point and will shut down your boiler/burner in cases where you exceed that set point. Brands such as Honeywell, Dwyer, Siemens, Johnson Controls, Ashcroft are common and we stock a wide range of those brands.
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What are Temperature Controls & what is their function?
Temperature Controls keep boilers operating in spec
Boilers are all about converting heat into steam. In order to do that in the safest and most efficient way, they require temperature controls that can adjust the boiler’s water or heat level as needed. That way, the entire combustion-to-steam-to-condensate cycle can be kept in proper balance for optimal performance.
Different Types of Temperature Controls & How to Choose
Temperature controls fall into two categories: mechanical aquastats, and electronic loop controllers.
Aquastats
Aquastats are mechanical sensors that rely on physics to operate. Every aquastat has a high limit and a low limit. If the temperature in an operating boiler is below the low limit, the boiler will fire. If the temperature inside the boiler reaches or exceeds the high limit, the aquastat will cut off combustion to prevent the boiler from overheating.
Loop Controllers
Loop controllers use electronic sensors to detect the temperatures inside a boiler. These sensors convert heat into an electronic signal. As the heat increases or decreases, the electronic signal sent to the boiler controller will change. Based on this signal, the control system will know the temperatures, and whether the boiler needs to fire, continue firing, or stop firing.
The Role Temperature Controls Play in a Boiler
Temperature controls preserve safety, efficiency, and longevity by keeping the boiler operating within specified temperatures. If the boiler were to run too hot, it shortens the life of the boiler by stressing the metal components. Over time, this stress can lead to warping, cracking, or even an explosion. If the boiler is allowed to run too cool, it will not produce enough usable steam to meet demand.
what is the Effect of a Bad Temperature Control?
When a temperature control starts to go bad, it may give inaccurate readings, or fail to cut off or increase boiler firing based on demand. This can cause a loss of steam pressure, increased steam pressure, or elevated or lowered stack temperatures.
Things to Consider about temperature controls:
- Because of their precision and constant feedback signal, loop controllers allow for greater efficiency — especially when installed in a system with electronically modulated valves.
Helpful Resources
Relevant WARE Videos on Temperature Controls
Monitoring Boiler Stack Temperature
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Revisiting Daily Boiler Maintenance
Getting Control of your Feed Water with the WARE Mod-V
Autoflame - The Leader in Combustion Management Controls
What Does the Low Fire Hold Switch Do? Pressure Control Series Episode Five
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Flame Safeguard Operations Part 2
Explore over 750+ explanatory videos on boilers and boiler systems on our Youtube channel. Our videos can help you quickly grasp complex boiler topics. Watch more here!
Relevant WARE Blog Articles on Temperature Controls
How to Manage Too Much Water in a Steam Boiler
Modulating Feedwater Valves: The Method Behind the Movement
What are the differences between a Gate Valve and a Globe Valve?
Boiler Open and Close: Preparation and Tips
Annual Steam Boiler Open and Close
Boiler Formulas and Measurements to Know
What Parts to Keep On-Hand at All Times
Our informative and educational blog content can help you gain a deeper understanding of the boiler room. Read more here!
Technical Documents
Temperature Controls FAQ
How do I know if my temperature control valve is operating properly?
Always check your stack temperatures regularly. If they’re consistently higher than normal, have your temperature controls checked to make sure they’re operating properly.
How can I tell if I have an aquastat or a loop controller?
Aquastats are purely mechanical. They will have a dial and a mechanical linkage to the boiler’s control system. Loop controllers, on the other hand, use sensors and electrical wiring to maintain communication with the boiler control system.