Install, commission and handover heat pumps _non-refrigerant circuits_ — EAL Occupational Qualification Construction & Building Services Revision
This subtopic focuses on the practical aspects of installing, testing, commissioning, and handing over non-refrigerant circuits for air and ground source h
Topic Synopsis
This subtopic focuses on the practical aspects of installing, testing, commissioning, and handing over non-refrigerant circuits for air and ground source heat pumps. It covers planning, site preparation, safe installation of the unit and its hydronic connections, system flushing and filling, commissioning checks, and final customer demonstration. Mastery ensures efficient heat pump operation and compliance with manufacturer and regulatory requirements.
Key Concepts & Core Principles
- Heat pump types and operating principles: Understand the difference between ground source (vertical or horizontal loops), water source, and air-to-water heat pumps, and how they extract heat from the environment using a refrigeration cycle (even though you don't work on the refrigerant circuit).
- System components: Know the function of key components like the evaporator, condenser, compressor, expansion valve, buffer tank, plate heat exchanger, circulation pumps, and expansion vessels. Recognise that the refrigerant circuit is sealed and pre-charged.
- Efficiency metrics: Coefficient of Performance (COP) and Seasonal Performance Factor (SPF) – how they are calculated and what affects them (e.g., flow temperatures, ground loop length, insulation).
- Installation requirements: Pipework sizing for low-temperature systems, underfloor heating vs. radiators, integration with existing heating systems, and the need for adequate insulation to minimise heat loss.
- Commissioning and maintenance: Procedures for filling, venting, pressure testing, setting flow rates, checking electrical connections, and fault-finding common issues like low pressure, air locks, or control failures.
Exam Tips & Revision Strategies
- Always reference the manufacturer’s installation manual and relevant Building Regulations Part L during practical tasks and written assignments to demonstrate due diligence.
- Create a detailed commissioning checklist in advance and methodically record all readings (temperatures, flow rates, pressures) as evidence for your portfolio.
- During handover role-plays, ensure you cover user controls, thermostat programming, filter cleaning, and emergency shutdown—not just normal operation.
- When installing, double-check electrical isolation and safe working practices; assessors will be observing compliance with health and safety requirements.
Common Misconceptions & Mistakes to Avoid
- Omitting system flushing before connecting the heat pump, leading to debris blocking the heat exchanger and reduced efficiency.
- Incorrectly sizing or positioning the expansion vessel, causing pressure-related faults or inadequate system volume compensation.
- Misinterpreting the heat pump controller settings, especially weather compensation curves, leading to poor comfort and high running costs.
- Failing to check the anticorrosion inhibitor concentration after filling, risking long-term corrosion damage to the non-refrigerant circuit.
Examiner Marking Points
- Award credit for demonstrating thorough planning that includes site survey, risk assessment, and selection of appropriate tools, materials, and personal protective equipment.
- Award credit for correct installation of pipework, isolation valves, filters, and expansion vessels, with evidence of system flushing and pressure testing to relevant standards.
- Award credit for systematic commissioning: verifying flow rates, temperature differentials, system controls, and completing a commissioning report that confirms the heat pump performs to specification.
- Award credit for a structured handover that includes clear explanation of system operation, maintenance requirements, and provision of all documentation to the customer.