Refrigeration training with Kelvin
Practice questions, worked examples and printable worksheets for UEE32225 Certificate III in Air Conditioning and Refrigeration: UEERA0036, and the CO₂ electives UEERA0066 and UEERA0006. Every answer is worked out by Kelvin, with the working shown, and there are no accounts to make.
UEERA0036 practice
Saturation, dew and bubble points, superheat and subcooling: the ideas, a worked example stepped through on R-454B, a guided exercise that checks each step, and a practice set of 17 questions with a new set of figures every time.
Every answer comes with Kelvin’s working, so a wrong answer shows where the method went astray.
CO₂ (R-744) practice
Saturation and standing pressures, the critical and triple points, subcritical and transcritical, superheat and subcooling on R-744, for UEERA0066 and the pressure–temperature side of UEERA0006, and for technicians moving onto CO₂ plant.
A worked example on a cascade’s low stage, a guided exercise, and a practice set of 11 questions, each with Kelvin’s working.
Printable worksheets
A worksheet for every student in either module, each with its own figures, so answers can’t simply be copied. The answer key shows the working for every sheet.
Each sheet carries a code that opens it online, for a student to check their answers after class.
The tools
The superheat and subcooling calculator, which shows its working; the printable P–T charts; and a table and P–h diagram for each refrigerant. Built for a phone, for use on site.
How a class uses it
- Before class
- Print a set of worksheets: one per student, each with different figures, and the answer key with the working.
- In class
- Students work the sheet by hand from a P–T chart, or practise on their phones. Each module’s practice set gives its kinds of calculation and a few questions on what the figures mean, with fresh figures whenever they want more.
- After class
- A student types their sheet’s code into the practice page to check every answer against Kelvin’s, with the working. You have the same answers in the key.
- The figures
- Worked out by Kelvin’s own engine on the public refrigerant tables computed with CoolProp 7.2.1dev. A blend’s superheat is read from its dew point and its subcooling from its bubble point. Nothing is extrapolated: a reading outside a table is never set as a question.
Mapped to UEE32225
| Unit | Questions that practise it |
|---|---|
| UEERA0036 practice | |
| UEERA0036Establish the basic operating conditions of vapour compression systems | Gauge to absolute pressure · A gauge reading in another gauge unit · Saturation temperature from a gauge · Expected gauge pressure at a temperature · Dew point of a blend from a gauge · Bubble point of a blend from a gauge · Superheat from the suction line · Subcooling from the liquid line · Line temperature for a target superheat or subcooling · Saturation temperature lost along the suction line · Superheat gained between the evaporator and the compressor · Glide of a blend at a pressure · The state of a refrigerant at a pressure and temperature · Which point superheat is read from · Which point subcooling is read from · What a negative superheat points to · What a gauge reads against |
| UEERA0052Install, commission, service and maintain low temperature systems | Saturation temperature from a gauge · Superheat from the suction line · Subcooling from the liquid line · What a negative superheat points to |
| UEERA0053Install, commission, service and maintain medium temperature systems | Saturation temperature from a gauge · Superheat from the suction line · Subcooling from the liquid line · What a negative superheat points to |
| UEERA0062Recover and charge refrigerants | Gauge to absolute pressure · A gauge reading in another gauge unit · Saturation temperature from a gauge · Expected gauge pressure at a temperature · Superheat from the suction line · Subcooling from the liquid line · What a gauge reads against |
| UEERA0079Safely handle refrigerants and lubricants | Dew point of a blend from a gauge · Bubble point of a blend from a gauge · Glide of a blend at a pressure · Which point superheat is read from · Which point subcooling is read from |
| UEERA0099Install, commission, service and maintain air conditioning systems | Expected gauge pressure at a temperature · Superheat from the suction line · Subcooling from the liquid line · What a negative superheat points to |
| CO₂ (R-744) practice | |
| UEERA0006Apply safety awareness and legal requirements for carbon dioxide refrigerant | Saturation temperature from a gauge · Standing pressure with the plant off · How far the standing pressure rises as the room warms · What sets the standing pressure, either side of the critical temperature · The triple or critical point pressure on a gauge · Whether liquid CO₂ can exist at a pressure |
| UEERA0047Install and commission carbon dioxide refrigeration systems, components and associated equipment | The state of R-744 at a pressure and temperature · Subcooling on a subcritical or cascade R-744 liquid line |
| UEERA0066Repair and service carbon dioxide refrigeration systems | Saturation temperature from a gauge · Gauge pressure at a saturation temperature · Standing pressure with the plant off · How far the standing pressure rises as the room warms · What sets the standing pressure, either side of the critical temperature · The triple or critical point pressure on a gauge · Whether liquid CO₂ can exist at a pressure · Subcritical or transcritical, from the high-side pressure · The state of R-744 at a pressure and temperature · Superheat on an R-744 suction line · Subcooling on a subcritical or cascade R-744 liquid line |
| UEERA0068Repair and service self-contained carbon dioxide refrigeration and heat pump systems | Subcritical or transcritical, from the high-side pressure · The state of R-744 at a pressure and temperature |
Unit codes and titles from training.gov.au. UEE32225 replaced UEE32220 on 24 March 2025 and is equivalent to it. The first module is built around UEERA0036 and the CO₂ module around UEERA0066; the other units use the same skills. The CO₂ module covers only the pressure–temperature side of UEERA0006, not its safety and legal requirements.
Pilot it with your class
Teaching UEE32225? Sentoro is looking for a class to pilot Kelvin with: what is on these pages, plus a class space where students hand in their work and you mark it, with Kelvin’s working beside each answer. The pilot is free; after it, the class space and the printable class sets come with an annual institute licence. Email hello@sentorotech.com.au.
Practice and teaching material
Practice and teaching material mapped to the unit's code. It isn't an RTO assessment tool: your assessment tools stay yours, and whether you use any of this as evidence is your call. Worked out in the browser. Nothing a student types is sent anywhere, and there are no accounts to make. The practice module, the calculator and the P–T charts are free. Printable class sets are open while Kelvin pilots with TAFE classes; after the pilot, they come with an institute licence, along with the class space for handing in and marking.