950-STOL1 Solar Thermal Open-Loop Troubleshooting Learning System
by Amatrol
Open-loop solar thermal systems are among the most common solar water heating configurations in residential and commercial applications, particularly in warmer climates where freeze protection requirements are less demanding. They are also among the most diverse in their design, ranging from simple thermosyphon configurations to PV-powered DC pump systems to more sophisticated draindown and pressurized designs with digital controllers, multiple sensors, and integrated freeze protection. A solar thermal technician who can only service one type of open-loop system is not fully prepared for the breadth of systems they will encounter in the field.
The Amatrol 950-STOL1 Solar Thermal Open-Loop Troubleshooting Learning System develops the comprehensive open-loop troubleshooting competency that solar thermal careers require. Through a unique combination of interactive multimedia eLearning curriculum and hands-on experience with a complete set of real industrial solar thermal components, the 950-STOL1 teaches students to connect, program, and troubleshoot both draindown and pressurized open-loop solar thermal systems at both the component and system level. The system supports portions of the NABCEP Certified Solar Thermal System Installer examination, connecting classroom training directly to the industry credential that solar thermal employers recognize.
Klein Educational supplies Amatrol alternative energy training systems to CTE programs, community colleges, and technical training centers across California, Oregon, Washington, Arizona, Nevada, Hawaii, and Alaska. As the only authorized Amatrol distributor in these seven states, we help programs get the right system configured and running.
What is the Amatrol 950-STOL1?
The Amatrol 950-STOL1 Solar Thermal Open-Loop Troubleshooting Learning System is a mobile workstation built around a wide variety of industry-standard solar thermal components that give students hands-on experience with the actual open-loop systems they will troubleshoot in the field. The workstation includes a digital differential controller, AC and DC centrifugal pumps, temperature probes, check valves, flow meters, relief valves, vacation bypass, tempering valves, a solar storage tank, multiple component circuit panels, a photovoltaic panel, and two solar collectors, covering the full range of components found in both draindown and pressurized open-loop solar thermal systems.
The inclusion of both AC and DC centrifugal pumps is a particularly important feature that reflects the actual variety of open-loop system designs students will encounter in the field. The DC pump is powered by a photovoltaic panel, replicating the PV-powered solar thermal system architecture commonly used in remote and off-grid applications where AC power is unavailable or where simple, self-powered operation is preferred. Students practice connecting and operating a PV-powered DC pump as a hands-on exercise that bridges solar PV and solar thermal knowledge in a realistic application context.
The digital differential controller features many programming capabilities, allowing students to learn to program and configure the more sophisticated controllers found in modern open-loop installations, including the freeze protection programming that is critical in climates that experience occasional freezing temperatures.
Fault insertion: electrical and fluid faults
The 950-STOL1 is equipped with a wide array of both electrical and fluid faults that allow instructors to replicate realistic component and system-level failures. This dual fault capability is essential for open-loop solar thermal troubleshooting training, where technicians must be equally comfortable diagnosing electrical problems in the pump, controller, and sensor circuits and fluid system problems in the piping, valves, and storage system.
Students learn to independently solve the many common types of problems they will encounter on the job, developing the systematic troubleshooting approach and diagnostic confidence that are the defining characteristics of a skilled solar thermal service technician. Instructors can replicate specific fault scenarios repeatedly across different students without equipment wear or preparation time, ensuring consistent training quality across the program.
What students and trainees learn
The 950-STOL1 curriculum covers the full range of solar thermal open-loop troubleshooting knowledge and hands-on skills across both draindown and pressurized system types.
Solar collector topics cover collector construction, operation, and performance characteristics, interpreting solar collector specifications, measuring collector output, collector efficiency analysis, and identifying collector faults and degradation.
Open-loop system component topics cover solar storage tank operation and sizing, air vent and vacuum valve function and troubleshooting, check valve operation and fault diagnosis, system charging procedures for open-loop configurations, freeze protection methods and analog controller operation, tempering valve operation and adjustment, and flow meter use for system performance verification.
PV-powered system topics cover photovoltaic panel operation in the solar thermal context, DC centrifugal pump connection and operation, PV-powered system operation and performance monitoring, and troubleshooting PV-powered solar thermal systems at both the component and system level.
Draindown system topics cover the unique operating characteristics of draindown open-loop systems, draindown valve operation and testing, freeze protection through the draindown mechanism, and draindown system-level troubleshooting including the most common draindown failure modes that result in freeze damage.
Pressurized open-loop system topics cover the unique operating characteristics of pressurized open-loop configurations, digital controller programming and adjustment, system pressure management, and pressurized system-level troubleshooting.
Overall system performance topics cover interpreting system operation data to assess performance, identifying degraded performance before complete failure occurs, and developing the systematic diagnostic approach that allows technicians to efficiently isolate root causes across complex multi-component system faults.
Indoor and outdoor training capability
The 950-STOL1's two solar collectors work either outside with direct sunlight or inside with the optional Solar Thermal Sun Simulator (95-STS1), which provides the heat energy needed to operate the system indoors. This indoor-outdoor flexibility ensures that solar thermal training can be scheduled consistently regardless of weather conditions, giving programs the same scheduling reliability for solar thermal curriculum that they have for any other lab activity.
Multimedia eLearning curriculum
The 950-STOL1 includes Amatrol's interactive multimedia eLearning curriculum covering open-loop solar thermal troubleshooting topics using text, audio, video, interactive quizzes, and 3D animations. The curriculum begins with foundational solar thermal components including collectors, pumps, and storage tanks, and advances steadily to more complex system operation, digital controller programming, PV-powered system troubleshooting, and draindown and pressurized system-level diagnosis.
The highly interactive format supports multiple learning styles including reading, listening, and visual approaches, with voiceovers of all text, 3D animations illustrating system operation and fault scenarios, and interactive exercises that verify comprehension before students advance to hands-on practice. Each theoretical concept is paired directly with a hands-on application task on the 950-STOL1 workstation. A Student Reference Guide compiled from the curriculum's technical content is included with the system.
How the 950-STOL1 fits in a complete solar thermal program
The 950-STOL1 is the open-loop counterpart to the 950-STCL1 Solar Thermal Closed-Loop Troubleshooting Learning System. Together, these two systems cover the full range of solar thermal system types that technicians encounter across residential and commercial solar water heating installations. Programs that deploy both systems alongside the 950-STF1 Solar Thermal Installation Training System build a complete solar thermal education pathway covering installation, closed-loop troubleshooting, and open-loop troubleshooting that comprehensively prepares students for the NABCEP Certified Solar Thermal System Installer examination.
How Klein Educational supports your program
Klein Educational is more than an equipment supplier. We work with program directors, department heads, and workforce administrators from the first conversation through delivery and beyond. That includes needs assessment, system configuration, and support to ensure your program gets the right 950-STOL1 setup for your curriculum and facility.
As the only authorized Amatrol distributor in California, Oregon, Washington, Arizona, Nevada, Hawaii, and Alaska, we have direct access to the full Amatrol alternative energy product line, curriculum, and support infrastructure.
Frequently asked questions
What is the Amatrol 950-STOL1? The 950-STOL1 is a solar thermal open-loop troubleshooting learning system built around a mobile workstation with real industrial solar thermal components including a digital differential controller, AC and DC centrifugal pumps, temperature probes, check valves, flow meters, relief valves, vacation bypass, tempering valves, a solar storage tank, multiple circuit panels, a photovoltaic panel, and two solar collectors. It includes both electrical and fluid fault insertion capability and interactive multimedia eLearning curriculum.
What open-loop system types does the 950-STOL1 cover? The system covers both draindown and pressurized open-loop solar thermal configurations, including PV-powered DC pump systems. Students can work with both draindown and pressurized system configurations on the same workstation.
Why does the 950-STOL1 include both AC and DC pumps? The DC centrifugal pump is powered by the included photovoltaic panel, replicating PV-powered solar thermal systems used in remote and off-grid applications. Students practice connecting and operating PV-powered pump systems as a hands-on exercise that reflects real open-loop system configurations in the field.
Can the 950-STOL1 be used indoors? Yes. The optional Solar Thermal Sun Simulator (95-STS1) provides the thermal energy needed to operate the system indoors, giving programs full scheduling flexibility regardless of weather conditions.
Does the 950-STOL1 support NABCEP certification? Yes. The 950-STOL1 curriculum supports the knowledge needed for the NABCEP Certified Solar Thermal System Installer examination.
Does Klein Educational help with system setup? Yes. Klein works with programs from needs assessment through system configuration and delivery, ensuring programs get the right solar thermal troubleshooting training setup for their curriculum and facility.
Ready to Build a Solar Thermal Open-Loop Training Program?
Whether you are adding open-loop solar thermal troubleshooting to an existing renewable energy curriculum or building a complete NABCEP solar thermal certification pathway, our team will help you find the right 950-STOL1 configuration for your needs and budget.