BPI Heating Professional (HEP) Overview
These study notes are designed to prepare candidates for the BPI Heating Professional (HEP) certification exam. The exam covers combustion science, airflow, equipment sizing, combustion safety, controls, and system performance testing. Candidates should verify all pass marks, eligibility, and specific requirements with BPI directly.
For Technical Conquer practice planning, this module is tracked as 100 questions over about 180 minutes with a listed pass mark of 70%. Treat those numbers as practice baselines and verify the current official format before scheduling.
How This Guide Is Organized
The sections below turn the syllabus into studyable subject blocks. Read a subject first, explain the must-know ideas without notes, then use questions, flashcards, and mind maps to test whether the knowledge holds under field-style pressure.
- Combustion Science and Fuel Delivery Systems
- Heating System Airflow and Distribution
- Equipment Sizing and Selection Criteria
- Combustion Safety and Venting Diagnostics
- Control Systems and Electrical Troubleshooting
- System Performance Testing and Commissioning
Exam Snapshot and Readiness Target
Format: 100 questions, 180 minutes, pass mark 70% (practice baseline; verify with BPI)
Candidate level: Entry-level for employment-ready technicians
Readiness target: Demonstrate knowledge of heating system fundamentals, safety, diagnostics, and performance testing
Most candidates should budget at least 42+ focused study hours, then adjust upward for unfamiliar equipment, code, regulatory, commissioning, controls, or calculation-heavy content.
Combustion Science and Fuel Delivery Systems
Syllabus Focus
- Combustion chemistry and stoichiometry
- Fuel types (natural gas, propane, oil) and properties
- Fuel delivery components (piping, regulators, valves, pumps)
- Combustion efficiency and flue gas analysis
Key Notes
- Complete combustion requires proper air-fuel ratio; excess air reduces efficiency but ensures safety.
- Flue gas analysis measures O2, CO2, CO, and stack temperature to calculate combustion efficiency.
- Natural gas is primarily methane; propane has higher BTU content per cubic foot.
- Fuel delivery systems must comply with IMC and NFPA 54/58 for piping and venting.
- Oil burners require proper atomization and ignition; nozzle size and spray pattern affect combustion.
- Draft over fire and flue draft must be within manufacturer specifications for safe operation.
Must Know
- Stoichiometric air-fuel ratio: ~10:1 for natural gas, ~15:1 for propane, ~14.7:1 for oil.
- Combustion efficiency formula: Efficiency = 100 - (stack temperature - room temperature) * (CO2% / 0.04) (simplified).
- Maximum allowable CO in flue gas: typically < 400 ppm for gas appliances (verify with BPI standards).
- Fuel gas pressure: natural gas typically 7" w.c. at meter, 3.5" w.c. at appliance; propane 11" w.c.
Field and Exam Application
- Measure flue gas O2, CO2, CO, and temperature using a combustion analyzer to tune burner.
- Check gas pressure at manifold with manometer; adjust regulator if needed.
- Inspect fuel lines for leaks using soap bubbles or electronic sniffer.
High-Yield Distinctions
- Difference between excess air and dilution air: excess air is for combustion, dilution air is for venting.
- Net stack temperature vs. gross stack temperature: net is flue temp minus ambient temp.
- Condensing vs. non-condensing furnaces: condensing units have secondary heat exchangers and lower flue temps.
Common Pitfalls
- Assuming high CO2 always means high efficiency; high CO2 with high CO indicates incomplete combustion.
- Ignoring draft conditions; poor draft can cause spillage or backdrafting.
- Using wrong fuel orifice size; propane orifices are smaller than natural gas.
Review Tasks
- Practice calculating combustion efficiency from flue gas data.
- Identify components of a gas train (shutoff valve, regulator, manifold, orifices).
- Review NFPA 54 and 58 requirements for fuel piping sizing.
Heating System Airflow and Distribution
Syllabus Focus
- Air properties and psychrometrics
- Duct design principles (ACCA Manual D)
- Airflow measurement techniques
- Fan performance and static pressure
Key Notes
- Airflow is critical for heat transfer; typical residential systems require 400 CFM per ton of cooling, but heating airflow varies.
- Static pressure is the resistance to airflow; total external static pressure (TESP) should be within manufacturer limits (usually 0.5" w.c.).
- Duct sizing must balance friction loss and velocity; Manual D provides design procedures.
- Psychrometric chart relates dry-bulb, wet-bulb, dew point, humidity ratio, and enthalpy.
- Airflow measurement methods: traverse, flow hood, pressure drop across coil (using manufacturer charts).
Must Know
- CFM = (BTU/h) / (1.08 * ΔT) for heating; ΔT is temperature rise across heat exchanger.
- Maximum duct velocity for residential: main trunk 900-1200 fpm, branches 600-900 fpm.
- TESP should not exceed 0.5" w.c. for most residential furnaces; verify with manufacturer.
- Return air must be at least as large as supply to avoid negative pressure.
Field and Exam Application
- Measure TESP using manometer at supply and return plenums; compare to blower table.
- Use flow hood to measure register airflow; compare to design CFM.
- Check temperature rise across heat exchanger to verify airflow; high rise indicates low airflow.
High-Yield Distinctions
- Supply static vs. return static: supply includes duct and register resistance; return includes filter and duct.
- Velocity pressure vs. static pressure: velocity pressure is dynamic, static is potential.
- Friction rate (FR) vs. velocity: Manual D uses FR of 0.1" w.c. per 100 ft as default.
Common Pitfalls
- Assuming filter pressure drop is negligible; dirty filters increase static and reduce airflow.
- Ignoring return air restrictions; undersized returns cause high static and noise.
- Using temperature rise alone to set airflow without considering humidity or latent heat.
Review Tasks
- Calculate required CFM for a given heat output and temperature rise.
- Measure TESP on a furnace and compare to manufacturer specs.
- Review ACCA Manual D duct sizing procedures.
Equipment Sizing and Selection Criteria
Syllabus Focus
- Heat loss/gain calculations (ACCA Manual J)
- Equipment selection (ACCA Manual S)
- Efficiency ratings (AFUE, HSPF, etc.)
- Load factors: infiltration, insulation, windows
Key Notes
- Manual J is the standard for residential load calculation; includes room-by-room and whole-house loads.
- Equipment should be selected based on Manual S, which matches load to equipment capacity at design conditions.
- AFUE (Annual Fuel Utilization Efficiency) measures furnace efficiency; minimum 80% for non-condensing, 90%+ for condensing.
- Oversizing leads to short cycling, reduced efficiency, and poor comfort; undersizing leads to inability to maintain setpoint.
- Infiltration load is calculated using ACH (air changes per hour) or blower door results.
Must Know
- Manual J design conditions: 99% dry-bulb for heating, 1% dry-bulb for cooling (from ASHRAE).
- Sensible heat loss formula: BTU/h = U * A * ΔT (for each building component).
- Equipment capacity must be within 1.4 times the load for heat pumps (Manual S).
- AFUE is steady-state efficiency; does not account for cycling losses.
Field and Exam Application
- Perform a room-by-room load calculation using Manual J software or worksheets.
- Select a furnace that meets the calculated load at design temperature without exceeding 140% of load.
- Verify equipment capacity at altitude; derate for high elevations.
High-Yield Distinctions
- Sensible vs. latent heat: heating is mostly sensible; cooling includes latent.
- Design temperature vs. average temperature: design is extreme, not average.
- Manual J vs. Manual S: J calculates load, S selects equipment.
Common Pitfalls
- Using rule-of-thumb (e.g., 50 BTU/sq ft) instead of Manual J; leads to oversizing.
- Ignoring duct losses; supply ducts in unconditioned space lose heat.
- Selecting equipment based on AFUE alone; capacity must match load.
Review Tasks
- Complete a sample Manual J calculation for a simple house.
- Compare equipment capacity to load for a given scenario.
- Review ASHRAE design conditions for your region.
Combustion Safety and Venting Diagnostics
Syllabus Focus
- Combustion air requirements (IMC, NFPA 54)
- Venting systems (Type B, direct vent, chimney)
- Spillage and backdrafting testing
- Carbon monoxide safety
Key Notes
- Combustion air must be provided from indoors or outdoors; IMC requires minimum opening area based on BTU input.
- Venting must be sized per manufacturer and code; common venting requires proper sizing to avoid spillage.
- Spillage occurs when flue gases exit the draft hood; test with a mirror or smoke pencil.
- Backdrafting is when combustion gases enter the living space; caused by negative pressure or blocked vent.
- CO alarms must be installed per NFPA 720; CO levels above 9 ppm require investigation.
Must Know
- Combustion air opening: 1 sq in per 1000 BTU for indoor air (two openings), 1 sq in per 4000 BTU for outdoor (one opening).
- Maximum CO in flue gas: < 400 ppm for gas furnaces (BPI standard).
- Spillage test: after 5 minutes of burner operation, no spillage for more than 1 minute.
- Vent connector rise: minimum 1/4" per foot slope upward.
Field and Exam Application
- Perform spillage test on a gas furnace using a mirror or smoke pencil at draft hood.
- Measure CO in flue gas and ambient air; if ambient CO > 9 ppm, shut down appliance.
- Inspect vent for obstructions, corrosion, or improper slope.
High-Yield Distinctions
- Category I vs. Category IV venting: Category I is non-condensing (Type B), Category IV is condensing (PVC/SS).
- Draft hood vs. barometric damper: draft hood is for gas, barometric for oil.
- Negative pressure vs. positive pressure: negative can cause backdrafting; positive can cause spillage.
Common Pitfalls
- Assuming a vent is sized correctly because it was existing; always verify per code.
- Not testing for spillage after installing a new appliance or vent.
- Ignoring the effects of exhaust fans (range hood, dryer) on negative pressure.
Review Tasks
- Practice spillage and backdrafting tests on a training appliance.
- Calculate combustion air opening size for a given BTU input.
- Review IMC Chapter 8 for venting requirements.
Control Systems and Electrical Troubleshooting
Syllabus Focus
- Thermostats and wiring (24V control)
- Safety controls (limit switches, flame rollout, pressure switches)
- Ignition systems (standing pilot, intermittent, hot surface, spark)
- Electrical troubleshooting (multimeter use, wiring diagrams)
Key Notes
- Low-voltage control circuits (24V) are common; transformer supplies power to thermostat and controls.
- Limit switches open on high temperature; rollout switches detect flame outside combustion chamber.
- Pressure switches prove airflow or draft; normally open or normally closed.
- Ignition systems: standing pilot is always on; intermittent pilot lights on call for heat; hot surface igniter glows; spark ignition uses spark.
- Multimeter measures voltage, resistance, and continuity; always check power off before measuring resistance.
Must Know
- Thermostat wiring: R (power), W (heat), Y (cool), G (fan), C (common).
- Limit switch setting: typically 180-200°F for gas furnaces; verify with manufacturer.
- Pressure switch: closes when draft is proven; if open, furnace won't start.
- Ignition sequence: call for heat → inducer → pressure switch → igniter → gas valve → flame sense.
Field and Exam Application
- Use multimeter to check transformer output (24V AC).
- Test limit switch for continuity; if open at room temp, replace.
- Check pressure switch tubing for blockages or leaks.
High-Yield Distinctions
- Normally open vs. normally closed switches: NO closes on condition, NC opens on condition.
- Hot surface igniter (HSI) vs. spark: HSI is a silicon carbide element; spark uses electrode.
- Single-stage vs. two-stage gas valves: two-stage provides low fire for better comfort.
Common Pitfalls
- Replacing a pressure switch without checking draft inducer operation.
- Assuming a thermostat is bad without checking for 24V at the terminals.
- Not following lockout sequences; some furnaces require power cycle to reset.
Review Tasks
- Trace a wiring diagram for a typical gas furnace.
- Practice measuring voltage and continuity on a control board.
- Review ignition sequence for different systems.
System Performance Testing and Commissioning
Syllabus Focus
- Commissioning procedures (BPI standards)
- Performance metrics (efficiency, temperature rise, static pressure)
- Blower door and duct leakage testing
- Reporting and documentation
Key Notes
- Commissioning verifies system operates per design and manufacturer specs; includes startup, testing, and documentation.
- Temperature rise across heat exchanger must be within nameplate range (typically 40-70°F).
- Static pressure test ensures airflow is adequate; high static indicates restriction.
- Duct leakage testing (duct blaster) measures total leakage; BPI standards require < 10% leakage for new systems.
- Blower door test measures building airtightness; used to calculate infiltration load.
Must Know
- Temperature rise formula: ΔT = (CFM * 1.08) / BTU output (rearranged to find CFM).
- Maximum duct leakage: 10% of total airflow for new construction (BPI).
- Commissioning report should include: model, serial, measurements, and any deficiencies.
- Combustion efficiency test: steady-state efficiency should be within manufacturer specs.
Field and Exam Application
- Perform a complete system test: measure gas pressure, temperature rise, static pressure, and flue gas.
- Use duct blaster to measure leakage to outside; seal leaks with mastic or tape.
- Document all readings and compare to specifications; note any issues.
High-Yield Distinctions
- Commissioning vs. troubleshooting: commissioning is for new or repaired systems; troubleshooting is for faults.
- Steady-state efficiency vs. AFUE: steady-state is instantaneous; AFUE is seasonal.
- Duct leakage to outside vs. total leakage: outside leakage is more critical for energy loss.
Common Pitfalls
- Skipping static pressure test; high static can cause premature motor failure.
- Not verifying gas input rate; orifice size and gas pressure affect input.
- Failing to document readings; lack of records can lead to callbacks.
Review Tasks
- Perform a mock commissioning on a furnace, recording all key measurements.
- Calculate duct leakage percentage from duct blaster results.
- Review BPI commissioning standards for heating systems.
How To Use These Notes With Practice Questions
Do not jump straight from reading to a full mock. Work by subject first: review the key notes, make a short recall sheet from memory, then answer a focused question set. After each miss, decide whether the problem was missing theory, weak code/source recall, poor measurement setup, calculation error, or a field sequence you did not visualize.
Technical Conquer's question bank, flashcards, mind maps, and spaced review tools are most useful after this instruction layer because they reveal which parts of the notes are not yet retrievable.
Final Review Checklist
- Review combustion efficiency calculations and flue gas analysis procedures.
- Practice airflow measurement and static pressure testing.
- Master Manual J load calculation and Manual S equipment selection.
- Understand combustion safety tests: spillage, backdrafting, CO measurement.
- Be able to troubleshoot control circuits and ignition systems.
- Know commissioning steps and documentation requirements.
- Verify all pass marks and exam details with BPI directly.
Official Sources and Further Reading
Use these sources as the final authority for format, eligibility, rules, regulatory limits, and exam updates. Study notes are a preparation layer, not a replacement for official candidate guidance.