Know the requirements to inspect, service and maintain heat pump system installations _non-refrigerant circuits_
This element covers the routine inspection, servicing, and maintenance of non-refrigerant circuit components in heat pump installations, including hydronic distribution systems, circulator pumps, strainers, expansion vessels, and control interfaces. It ensures learners can perform scheduled maintenance tasks, diagnose common faults such as flow irregularities or sensor failures, and rectify issues safely to maintain system efficiency and compliance with manufacturers’ specifications and industry standards.
Assessment criteria
Topic Overview
The City & Guilds Level 3 Award in the Installation and Maintenance of Heat Pump Systems (Non-refrigerant Circuits) focuses on the practical skills and knowledge required to install, commission, and maintain heat pump systems that do not involve handling refrigerants. This qualification covers air source, ground source, and water source heat pumps, emphasising the non-refrigerant aspects such as pipework, controls, and electrical connections. It is designed for experienced heating and plumbing professionals looking to expand into renewable technologies, aligning with the UK's net-zero targets and the growing demand for low-carbon heating solutions.
This award is part of the wider Construction & Building Services sector, specifically within the heating and ventilation pathway. It equips learners with the competence to work on heat pump systems safely and efficiently, ensuring compliance with building regulations (e.g., Part L of the Building Regulations) and industry standards (e.g., MCS 010). By mastering this topic, students can contribute to reducing carbon emissions in domestic and commercial buildings, making it a vital skill for modern heating engineers.
The curriculum covers system design principles, installation procedures, commissioning checks, fault finding, and routine maintenance. Students learn to interpret technical manuals, select appropriate components, and use diagnostic tools. Practical assessments ensure hands-on competence, while theory tests verify understanding of thermodynamics, system efficiency, and safety protocols. This qualification is a stepping stone to further certifications, such as the full heat pump installation qualification or the Level 3 Award in Refrigerant Handling.
Key Concepts
Core ideas you must understand for this topic
- →Heat pump types and operating principles: Understand the difference between air source, ground source, and water source heat pumps, and how they extract heat from the environment using a refrigeration cycle (even though you don't handle refrigerant, you must understand the cycle).
- →System components: Identify and explain the function of key non-refrigerant components, including heat exchangers, circulation pumps, expansion vessels, buffer tanks, and controls (thermostats, weather compensation, and zone valves).
- →Installation requirements: Know the correct procedures for siting outdoor units, laying ground loops (slinky or borehole), connecting pipework, and ensuring adequate airflow and drainage.
- →Commissioning and testing: Perform pre-commissioning checks (e.g., pressure testing, electrical continuity), set controls, measure flow rates and temperatures, and verify system efficiency using manufacturer specifications.
- →Maintenance and fault diagnosis: Carry out routine maintenance tasks (cleaning filters, checking pressures, inspecting electrical connections) and use systematic fault-finding techniques to identify common issues like low flow rate, incorrect refrigerant charge (though you don't handle it, you must recognise symptoms), or control faults.
Learning Objectives
What you need to know and understand
- Know the requirements for the non-refrigerant circuit routine service and maintenance of heat pump system installations, Know how to diagnose faults in heat pump system installations, Know how to rectify non-refrigerant circuit faults in heat pump system installations
Assessment Criteria
Key criteria assessors look for in your portfolio
- Award credit for demonstrating correct isolation procedures (electrical and hydronic) before any service or maintenance task.
- Award credit for accurately recording service checks, including system pressures, flow rates, and component condition, on a service report or log.
- Award credit for applying a logical fault-finding sequence that prioritises non-invasive checks (e.g., visual inspection, controller fault codes) before invasive testing.
- Award credit for correctly identifying and replacing common faulty components in the non-refrigerant circuit, such as pump cartridges or blocked filters, while confirming operation post-repair.
Assessment Guidance
Guidance for achieving higher grades
- 💡Always consult the manufacturer’s installation and maintenance manual specific to the heat pump model, as requirements for non-refrigerant circuits can vary significantly.
- 💡Use a systematic diagnostic approach: check simple, external components (e.g., fuses, isolators, and user settings) before moving to complex controls or wiring.
- 💡Document all findings and actions thoroughly; incomplete or inaccurate service records are a common reason for assessment penalties in practical assignments.
- 💡Tip 1: Always refer to manufacturer instructions during practical assessments. Examiners look for evidence that you follow specific guidance for each system, not just generic procedures.
- 💡Tip 2: In written exams, use technical terms correctly (e.g., 'coefficient of performance' not 'efficiency ratio') and explain the 'why' behind steps, not just the 'what'. For example, explain why you check flow rate (to ensure adequate heat transfer).
- 💡Tip 3: For fault-finding questions, use a logical approach: start with the simplest checks (power supply, settings) before moving to complex components. Show your thought process clearly.
Common Mistakes
Common errors to avoid in your coursework
- Overlooking the correct procedure for bleeding air from the system after maintenance, leading to pump cavitation or circulation issues.
- Confusing symptoms of a faulty circulator pump (e.g., no flow, noisy operation) with those of a blocked filter or closed isolation valve.
- Failing to verify system filling pressure and expansion vessel charge before diagnosing electrical faults, which can waste time on incorrect diagnostics.
- Misconception: Heat pumps only work in well-insulated homes. Correction: While good insulation improves efficiency, modern heat pumps can operate effectively in older properties with lower temperature emitters (e.g., oversized radiators or underfloor heating). Proper system design is key.
- Misconception: You don't need to understand the refrigerant circuit because you're not handling it. Correction: You must understand the basic refrigeration cycle to diagnose performance issues (e.g., low pressure indicates a leak) and to communicate effectively with refrigerant-qualified colleagues.
- Misconception: Commissioning is just turning the system on. Correction: Commissioning involves a systematic process of checking flow rates, temperature differentials, electrical safety, and control settings. Missing steps can lead to poor performance or system failure.
Frequently Asked Questions
Common questions students ask about this topic
Pass / Merit / Distinction Evidence Checklist
How your portfolio evidence is graded for CITY AND GUILDS OF LONDON INSTITUTE Know the requirements to inspect, service and maintain heat pump system installations _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
- •Level 2 qualification in Plumbing or Heating and Ventilation (e.g., City & Guilds Level 2 Diploma in Plumbing Studies) or equivalent experience.
- •Basic understanding of electrical principles (e.g., voltage, current, wiring diagrams) as heat pump systems involve electrical connections and controls.
- •Familiarity with building regulations Part L (Conservation of Fuel and Power) and Part P (Electrical Safety) is beneficial.
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Key Terminology
Essential terms to know
- Know the requirements for the non-refrigerant circuit routine service and maintenance of heat pump system installations, Know how to diagnose faults in heat pump system installations, Know how to rectify non-refrigerant circuit faults in heat pump system installations
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