Plan, prepare, install, commission, and maintain air source heat pump systems (non-refrigerant circuits)
This element focuses on the practical skills and knowledge required to safely and effectively work on the non-refrigerant (water/heating) side of air source heat pump installations. It covers all stages from initial planning and installation through to commissioning, handover, routine maintenance, and fault diagnosis, ensuring systems operate efficiently and comply with industry standards. The practical application involves integrating heat pumps into domestic or small commercial heating and hot water systems, emphasising hydraulic design, electrical connections, control setup, and customer awareness.
Assessment criteria
Quick Revision Summary (Key Takeaway)
The BPEC Level 3 Award in Air Source Heat Pump Systems (non-refrigerant Circuits) covers the installation, commissioning, and maintenance of air source heat pumps, focusing on non-refrigerant aspects such as pipework, controls, and system integration. It is essential for heating engineers working with renewable technologies in UK domestic and commercial buildings.
Topic Overview
This qualification focuses on the non-refrigerant side of air source heat pump (ASHP) systems, covering the installation, commissioning, and maintenance of the hydraulic and electrical components. It is designed for heating engineers who already hold relevant qualifications (e.g., Gas Safe or OFTEC) and wish to expand into renewable technologies. The course emphasises safe working practices, system design principles, and compliance with UK building regulations (Part L and Part P).
Key topics include understanding the heat pump cycle (without refrigerant handling), sizing and selecting components such as buffer tanks, expansion vessels, pumps, and controls. Students learn to interpret manufacturer datasheets, calculate flow rates and pressure drops, and commission systems to achieve optimal efficiency. The qualification also covers fault-finding and maintenance procedures for common issues like low flow rates or incorrect differential pressures.
Mastering this topic is crucial for meeting the UK's net-zero targets, as ASHPs are a key technology for decarbonising heating. Engineers with this qualification can confidently install systems that reduce carbon emissions and lower energy bills for homeowners. The knowledge also forms a foundation for further study in refrigerant circuits or other renewable technologies.
Key Concepts
Core ideas you must understand for this topic
- →Primary and secondary circuits: The primary circuit contains the water/glycol mixture between the heat pump and a buffer tank or heating system; the secondary circuit is the central heating or hot water system.
- →Buffer tanks: Their role in preventing short cycling, providing thermal mass, and aiding defrost cycles.
- →Expansion vessels and pressure relief valves: Sizing and positioning to maintain system pressure and safety.
- →System controls: Weather compensation, thermostatic radiator valves, and cylinder thermostats for efficient operation.
Learning Objectives
What you need to know and understand
- Learning Outcome 1. Plan and prepare for the installation of an air source heat pumps (non-refrigerant circuits).Learning Outcome 2. Install an air source heat pump unit (non-refrigerant circuits).Learning Outcome 3. Test and commission an air source heat pump system (non-refrigerant circuits).Learning Outcome 4. Handover an air source heat pump installation (non-refrigerant circuits).Learning Outcome 5. Know the requirements for non-refrigerant circuit routine service and maintenance of an air source heat pump system installation (non-refrigerant circuits).Learning Outcome 6. Undertake the non-refrigerant circuit routine service and maintenance of an air source heat pump system (non-refrigerant circuits). Learning Outcome 7. Undertake non-refrigerant circuit fault diagnosis work on an air source heat pump system installation.
Assessment Criteria
Key criteria assessors look for in your portfolio
- Award credit for demonstrating a systematic approach to planning, including accurate heat loss calculations, equipment selection, and regulatory compliance checks.
- Award credit for correct installation of hydraulic components, ensuring flow and return pipework is appropriately sized, insulated, and free from leaks.
- Award credit for thorough commissioning procedures, including flow rate verification, system balancing, and performance checks aligned with manufacturer’s instructions.
- Award credit for a comprehensive handover that includes user instruction, documentation provision, and demonstration of control operation.
- Award credit for identifying and safely executing routine maintenance tasks, such as strainer cleaning, inhibitor level checks, and expansion vessel testing.
- Award credit for logical fault diagnosis, using system knowledge and test equipment to isolate non-refrigerant circuit issues, and proposing effective remediation.
Assessment Guidance
Guidance for achieving higher grades
- 💡Always reference the manufacturer’s instructions and relevant industry guidance documents during planning and installation evidence.
- 💡In practical assessments, narrate your actions clearly to demonstrate underpinning knowledge, especially safety and regulatory justifications.
- 💡For written assignments, structure answers around the key stages: plan, install, commission, handover, service, and fault find, reflecting the unit's learning outcomes.
- 💡Ensure your evidence includes photographic records with annotations explaining key installation and commissioning steps.
- 💡Practice calculating flow rates and pressure drops for different heat pump outputs to reinforce hydraulic design principles.
- 💡When diagnosing faults, adopt a methodical approach: gather information, narrow down the possible causes, test logically, and record findings.
- 💡Always show your working in calculations, including units. Marks are awarded for method even if the final answer is slightly off.
- 💡Use correct terminology: 'flow temperature' not 'hot water temperature', 'return temperature' not 'cold water temperature'.
- 💡Refer to current regulations: Part L of Building Regulations (conservation of fuel and power) and Part P (electrical safety) are frequently tested.
Common Mistakes
Common errors to avoid in your coursework
- Neglecting to verify system design parameters against actual site conditions before commencing installation.
- Incorrectly sizing or positioning expansion vessels, leading to pressure issues.
- Overlooking the need to thoroughly flush and treat the primary system water to prevent corrosion and sludge build-up.
- Failing to correctly set up and explain the heating controls to the end-user, resulting in inefficient operation.
- Misinterpreting electrical wiring diagrams, causing control circuit faults and component damage.
- Rushing the commissioning process, skipping verification steps like flow rate measurement or performance data recording.
- Misconception: Air source heat pumps work efficiently in all outdoor temperatures. Correction: Efficiency drops as outdoor temperature falls; below -5°C, backup heaters may be needed.
- Misconception: The heat pump can be connected directly to existing radiators without modification. Correction: Existing radiators may need to be oversized or replaced to work with lower flow temperatures (35-45°C).
- Misconception: Glycol is optional in the primary circuit. Correction: Glycol is essential to prevent freezing in outdoor pipework and to protect against frost damage.
Revision Plan
How to revise this topic in 1–2 weeks
- 1Week 1: Focus on system components - buffer tanks, expansion vessels, pumps, and valves. Draw diagrams of primary and secondary circuits.
- 2Week 2: Practice calculations for flow rates, pressure drops, and system sizing. Use manufacturer datasheets.
- 3Week 3: Study commissioning procedures and fault-finding. Create a checklist for commissioning steps.
- 4Week 4: Review regulations and complete past exam questions. Focus on command words like 'explain' and 'calculate'.
Exam Question Types
How this topic typically appears in the exam
- 📋Multiple-choice questions on component functions and safety devices.
- 📋Short-answer questions requiring definitions or explanations (e.g., 'What is the purpose of a buffer tank?').
- 📋Calculation questions involving flow rate, heat output, or pressure drop.
- 📋Extended response questions (6 marks) asking to describe installation procedures or fault-finding steps.
Command Word Expectations (BPEC CERTIFICATION LTD)
What examiners look for when using specific command words in this specification
Provide a detailed account of how or why something works, including reasons and mechanisms. For example, 'Explain the role of a buffer tank in an ASHP system.'
Use a formula to determine a numerical value. Show all steps and include units. For example, 'Calculate the flow rate required for a 12 kW heat pump with a 5°C temperature drop.'
Give a step-by-step account of a procedure or the features of a component. For example, 'Describe the commissioning process for an ASHP system.'
How Students Lose Marks (Examiner Pitfalls)
Common mark loss traps and how to write 100% full-mark answers
Step-by-Step Worked Solutions
Detailed solution breakdown for typical exam problems
Question: A property has a design heat loss of 8 kW. The chosen air source heat pump has a nominal output of 10 kW at 7°C outdoor temperature. Calculate the required flow rate in litres per minute for the heating circuit if the design temperature drop is 5°C. (Specific heat capacity of water = 4.18 kJ/kg°C, density = 1 kg/litre)
- 1.Step 1: Use the formula: Heat output (kW) = Flow rate (kg/s) × Specific heat capacity (kJ/kg°C) × Temperature drop (°C).
- 2.Step 2: Rearrange to find mass flow rate: Flow rate (kg/s) = Heat output (kW) / (4.18 × 5) = 10 / 20.9 = 0.4785 kg/s.
- 3.Step 3: Convert to litres per minute: 0.4785 kg/s × 60 s/min = 28.71 litres/min (since density = 1 kg/litre).
Question: Explain the purpose of a three-port diverter valve in an air source heat pump system that provides both space heating and domestic hot water.
- 1.Step 1: Identify the two modes: space heating and hot water generation.
- 2.Step 2: Describe the valve's function: It diverts the flow from the heat pump to either the heating circuit or the hot water cylinder.
- 3.Step 3: Explain control: The valve is actuated by a signal from the system controller based on demand.
Active Recall Memory Test
Test your memory before revealing the key facts
Frequently Asked Questions
Common questions students ask about this topic
Pass / Merit / Distinction Evidence Checklist
How your portfolio evidence is graded for BPEC CERTIFICATION LTD Plan, prepare, install, commission, and maintain air source heat pump systems (non-refrigerant circuits)
Every vocational unit is marked against named criteria rather than an exam percentage. Your tutor's brief lists the exact codes for this unit — here is what each band is asking you to do.
Demonstrate baseline knowledge, accurate terminology, and core practical application.
Provide detailed analysis, structured explanations, and clear workplace reasoning.
Deliver thorough evaluation, original problem solving, and fully justified recommendations.
Before You Start
Prior knowledge that will help with this topic
- •Basic understanding of central heating systems (boilers, radiators, pipework).
- •Knowledge of electrical principles (voltage, current, wiring) for controls and pumps.
- •Familiarity with building regulations Part L and Part P.
Coursework AI Review
Paste your assignment brief and check your draft against its P/M/D criteria
Key Terminology
Essential terms to know
- Learning Outcome 1. Plan and prepare for the installation of an air source heat pumps (non-refrigerant circuits).Learning Outcome 2. Install an air source heat pump unit (non-refrigerant circuits).Learning Outcome 3. Test and commission an air source heat pump system (non-refrigerant circuits).Learning Outcome 4. Handover an air source heat pump installation (non-refrigerant circuits).Learning Outcome 5. Know the requirements for non-refrigerant circuit routine service and maintenance of an air source heat pump system installation (non-refrigerant circuits).Learning Outcome 6. Undertake the non-refrigerant circuit routine service and maintenance of an air source heat pump system (non-refrigerant circuits). Learning Outcome 7. Undertake non-refrigerant circuit fault diagnosis work on an air source heat pump system installation.
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