- What the Issuer Actually Publishes About the Exam
- The Exam at a Glance: What Is and Isn't Verified
- Domains 1 and 3: Components and the Heat Pump Cycle
- Domains 2 and 5: Controls and Theory
- Domains 6 and 7: Schematics and Troubleshooting
- Domain 4: Service
- Where the High Performance Heat Pumps Curriculum Fits
- Sequencing the Domains in Your Study Plan
- Keeping Service, Installer and Employment Ready Apart
- Frequently Asked Questions
- The exam is ESCO Group's Heat Pump Service, Professional Level - Written, administered through HVAC Excellence, with 100 closed-book questions.
- Seven subjects are published: components, controls, heat pump cycle, service, theory, interpreting schematics, and troubleshooting.
- Domain weights are unpublished, so no single domain can honestly be called the heaviest.
- Two years of verified field experience and the separate CORE exam are prerequisites.
What the Issuer Actually Publishes About the Exam
Most pages about this credential talk loosely about "the heat pump exam" and then paste in a tidy seven-part weighted blueprint. Here is what the issuer actually shows. The Heat Pump Service examination description on the ESCO Group Professional Technician Certifications page, administered through HVAC Excellence, lists seven subjects in a specific order. That is the extent of the official breakdown: seven named subjects, no percentages, no question counts per subject, and no published revision identifier.
That distinction matters for how you study. If you read a guide that claims "troubleshooting is 30% of the exam," it has invented the number. This guide treats the seven subjects as what they are: the official scope of the written exam, in published order, with equal presumption of importance until the issuer says otherwise. For the broader picture of what the credential is and who holds it, see What Is HPSC Certification? and the overview at HPSC Certification.
The Exam at a Glance: What Is and Isn't Verified
Before diving into domains, it helps to separate confirmed facts from open questions. Candidates routinely lose time chasing numbers that the issuer pages simply do not publish.
| Item | Status |
|---|---|
| Issuer / administering body | ESCO Group, through HVAC Excellence (verified) |
| Exam title | Heat Pump Service, Professional Level - Written (verified) |
| Question count | 100 questions, closed book, comprehensive (verified) |
| Response format | Described only as "written"; multiple-choice is not confirmed |
| Content subjects | Seven, unweighted (verified) |
| Prerequisites | Two years of verified field experience plus the separate CORE exam (verified) |
| Testing provider | ESCO/HVAC Excellence proctor network; not a verified Pearson VUE, PSI or Prometric arrangement |
| Exam fee, passing score, timer, retakes, validity, renewal | Not publicly verified in the issuer pages reviewed |
You will see third-party claims of a two-hour timer or a 70% pass mark. Those have not been confirmed by the issuer, so treat them as unverified. Our articles on the HPSC passing score, certification cost and exam dates and scheduling explain what can and cannot be stated with confidence. For eligibility mechanics, read HPSC Requirements.
Domains 1 and 3: Components and the Heat Pump Cycle
The first and third subjects are the physical foundation of everything else. A technician who cannot name what a reversing valve does, or trace refrigerant through a heating-mode cycle, will struggle with the troubleshooting and schematic subjects later.
Domain 1: Components
Expect to recognize what each major part does, how it fails, and what a failed part looks like in measurements.
- Compressor types and how a weak or mechanically failing compressor presents (low capacity, abnormal amp draw, equalized pressures)
- Reversing valve operation, including the pilot-and-slide principle and what a leaking or stuck valve does to the system
- Metering devices, including fixed orifice, thermostatic expansion valves and, in newer equipment, electronic expansion valves
- Indoor and outdoor coils, defrost sensors, and the accumulator and its role in protecting the compressor
- Contactors, capacitors, crankcase heaters and the electrical parts that start and protect the compressor and fan motors
- Variable-speed and inverter-driven components, which the issuer-linked preparation material emphasizes
Domain 3: Heat Pump Cycle
This is where a heat pump differs from a cooling-only system, and where many candidates with strong air conditioning backgrounds get caught.
- Refrigerant flow in cooling versus heating mode, including which coil acts as the evaporator in each
- How the reversing valve changes the roles of the indoor and outdoor coils
- Pressure and temperature relationships on the high and low sides in each mode
- Defrost cycle logic: why frost forms, how the system briefly reverses, and what supplemental heat does during it
- Why heating-mode charging and diagnosis differ from the cooling-mode habits many technicians learned first
- Capacity and efficiency changes as outdoor temperature drops
A useful drill: draw the cycle twice, once for each mode, and label the state of the refrigerant (high-pressure vapor, high-pressure liquid, low-pressure liquid-vapor mix, low-pressure vapor) at every point. If you can do that from memory with the reversing valve in both positions, you have the structure that later domains hang on. The full domain map is also summarized in our domains guide.
Domains 2 and 5: Controls and Theory
Controls and theory are the two subjects candidates most often underestimate because they feel abstract compared with hands-on service. They also quietly underpin the diagnostic questions.
Domain 2: Controls
Heat pump control logic is where comfort complaints often originate.
- Thermostat staging and what the O or B reversing valve terminal means for energized-in-cooling versus energized-in-heating systems
- Defrost control boards, thermistors and the conditions that start and end a defrost cycle
- Outdoor temperature lockouts for auxiliary heat and balance-point concepts
- High- and low-pressure switches, safety lockouts and how to tell a safety trip from a component failure
- Low-voltage control circuits, transformers, fuses and common wiring faults between the thermostat, air handler and outdoor unit
- The role of smart thermostats and communicating controls, which the issuer-linked preparation resource discusses under efficiency and diagnostics
Domain 5: Theory
Theory is the reasoning layer: why the system behaves as it does, not just what to replace.
- Heat transfer, sensible and latent heat, and the relationship between pressure and saturation temperature
- Superheat and subcooling as diagnostic tools and what each reveals about charge and metering
- Basic electrical theory: voltage, current, resistance, Ohm's law, and how motors and capacitors behave
- Airflow, static pressure and the relationship between airflow and capacity
- Efficiency concepts and why heating capacity falls as outdoor temperature falls
Domains 6 and 7: Interpreting Heat Pump Schematics and Troubleshooting
The last two subjects are where certification differs most from simple parts knowledge. They test whether you can read a diagram and reason from a symptom to a cause. Because the issuer publishes no question allocation, we cannot say how many questions fall here, but these subjects reward the deepest practice.
Domain 6: Interpreting Heat Pump Schematics
Schematic questions test reading skill, not memorization of a single manufacturer's wiring.
- Reading ladder diagrams: power on the rails, loads on the rungs, switches and sensors in series with the loads they control
- Telling apart a wiring diagram (physical layout) from a ladder or schematic diagram (logical flow)
- Tracing the path that energizes the contactor, the reversing valve solenoid and the defrost circuit
- Recognizing standard symbols for contactors, relays, capacitors, thermistors, pressure switches and transformers
- Predicting what happens when one element opens or shorts, which is the bridge into troubleshooting
Domain 7: Troubleshooting
Think in terms of symptom, hypothesis, test, conclusion.
- Systematic diagnosis starting from the complaint (no heat, ice on the outdoor coil, short cycling, high bills) and narrowing by measurement
- Distinguishing a refrigerant-side problem (charge, restriction, reversing valve) from an electrical or airflow problem
- Using pressures, temperatures, superheat, subcooling and amp draw together rather than any one reading alone
- Diagnosing a reversing valve that fails to shift, and defrost cycles that never start or never terminate
- Recognizing when a symptom points to controls versus a failed mechanical component
Here is an original practice scenario (not a recalled exam question). A heat pump runs normally in cooling but delivers weak heat, and the outdoor coil is partially frosted even though the unit has been running for some time. The suction line and the line leaving the reversing valve are nearly the same temperature. Where would you look first? The temperature similarity suggests refrigerant is bypassing inside the reversing valve, so you would confirm with pressure readings (compressor not producing a strong high-low split) before condemning the valve. Practicing this kind of cross-checking, rather than jumping to a single measurement, is exactly what the troubleshooting subject rewards. For a sense of difficulty, see How Hard Is the HPSC Exam?.
Domain 4: Service
The service subject covers the practical procedures that follow diagnosis: how you actually correct a problem safely and correctly. Because the exam title is Heat Pump Service, this subject frames how every other subject is applied.
Domain 4: Service
- Safe refrigerant handling and recovery practices consistent with your field's regulatory requirements
- Charging approaches and why the correct method depends on the metering device and operating mode
- Leak detection, evacuation and the basics of pulling and verifying a proper vacuum
- Replacing and testing common components such as capacitors, contactors, motors and reversing valve solenoids
- Cleaning and maintenance tasks that preserve capacity, including coil care and filter and airflow checks
- Commissioning and verification: confirming performance after service rather than assuming the repair worked
Good service answers usually emphasize verification: measure before, repair, measure after. That habit appears across the service and troubleshooting subjects and mirrors how experienced technicians actually work.
Where the High Performance Heat Pumps Curriculum Fits
The seven published subjects read like a traditional service syllabus, while many modern systems rely on inverter compressors, cold-climate designs and dual-fuel setups. The issuer-linked preparation resource, High Performance Heat Pumps by Clifton Beck (ESCO Institute, 2025), bridges that gap. Its preface explicitly connects that supplement, alongside Heat Pump Operation, Installation, and Service, to preparation for the HVAC Excellence Heat Pump Service exam.
The ten chapter headings visible in its public 44-page preview are:
- Heat Pump Fundamentals
- Inverter Operation
- Cold Climate Heat Pump Specifications
- Smart Thermostats and System Efficiency
- Ducted Heat Pump Systems
- Ductless Heat Pump Systems
- Retrofitting Fossil Fuel Systems
- Heat Pump Design and Selection
- Heat Pump Installation Best Practices
- System Commissioning with Smart Diagnostic Tools
The HVAC Excellence Competency and Task List is another linked resource, but its spreadsheet contents could not be retrieved, so this guide does not reconstruct task-level details from it. The issuer describes it as a broad educational competency list. For a structured way to use these resources, see our HPSC study guide and the overview of HPSC training options.
Sequencing the Domains in Your Study Plan
Since weights are unpublished, a sensible plan covers all seven subjects and spends extra time where you are weakest. The sequence below orders them by dependency: you need the cycle and components before diagnostics make sense.
Foundations: Theory, Components, Cycle
- Confirm CORE exam readiness if you have not passed it
- Draw the heating and cooling cycles with the reversing valve in each position
- Build a one-page component sheet: function, failure symptom, test method
Controls and Schematics
- Trace defrost and reversing valve circuits on ladder diagrams
- Practice predicting the effect of an open or shorted element
- Review thermostat terminals and staging logic
Service and Troubleshooting
- Work symptom-to-cause scenarios using pressures, temperatures and amp draw together
- Review charging, evacuation and verification procedures
- Add inverter and cold-climate concepts from your preparation reading
Adjust the length to your experience; a technician with years in the field may compress the early weeks, while someone newer to heat pumps specifically may extend them. Timed practice helps with the closed-book, 100-question format, and you can use the questions on the main practice test site to find weak domains early. A condensed review is available in the HPSC cheat sheet.
Keeping Service, Installer and Employment Ready Apart
Search results blur these credentials together, and some third-party practice pages even combine installer and service wording. The differences matter for what you study and what you can claim on a résumé.
| Credential | What it is |
|---|---|
| Heat Pump Service (Professional Level - Written) | The exam covered here: seven subjects, 100 questions, two-year experience and CORE prerequisites |
| Heat Pump Installer | A separate installation-track credential; its content emphasis differs |
| Heat Pumps Employment Ready | An entry-level credential, not interchangeable with the Professional Level service exam |
| NATE specialty | A different certifying body and exam family |
| Course-completion verification | Proof of finishing a training course, not the professional examination itself |
One related note: the ESCO Energy Skilled page associates the service credential with Heat Pump Comfort Advisor recognition and distinguishes the installation track. That recognition is a pathway label, not a new exam, and the preview's mention of supplemental training for service credentials earned before May 2023 is not an exam-version date or a renewal rule. Validity and renewal terms were not verified, so confirm directly with the issuer. If you are weighing the career value, our guides on whether the certification is worth it, salary context and HPSC jobs cover the employment side without inventing a pay premium. For reference, the Bureau of Labor Statistics reports a median annual pay of USD 61,010 (May 2025) for the broad heating, air conditioning and refrigeration mechanic and installer occupation; that figure describes the whole occupation, not certificate holders specifically.
Key Takeaway
Treat all seven subjects as in scope, anchor your study in the cycle and schematics, and use scenario-based practice for troubleshooting. Avoid any resource that claims actual exam questions or invented domain percentages; the issuer publishes neither. Sharpen your weak areas with the practice questions at the HPSC Exam Prep practice test site.
Frequently Asked Questions
The issuer's Heat Pump Service examination description lists seven subjects: components, controls, heat pump cycle, service, theory, interpreting heat pump schematics, and troubleshooting. They are unweighted subjects, not a published weighted blueprint.
That cannot be determined. The issuer does not publish question allocation or domain weights, so any claim that one subject is the largest is unverified. Prepare across all seven.
The exam has 100 questions and is a closed-book, comprehensive written assessment. The issuer page does not establish the exact response format beyond "written," so multiple-choice should not be assumed as official.
Two years of verified field experience and the separate Principles of Electrical and Refrigeration Theory CORE examination. No mandatory degree or fixed course-hour requirement was located. See HPSC Requirements for details.
These were not publicly verified in the issuer pages reviewed, and figures such as a two-hour limit or 70% pass mark appear only in unverified third-party sources. Confirm current terms with ESCO/HVAC Excellence before registering. Related background is in our guides on pass rate data and certification cost.