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Follow the water from the cold feed to the tap. The free question set checks how stored and instantaneous systems work, how temperature is controlled for both Legionella and scalding, and what you would check when a system runs cold, discharges or delivers lukewarm water.
Compare how each system is fed, where the expansion of heated water goes and what limits the flow at the tap. A stored system serves several outlets from its reserve; an instantaneous heater is limited by how fast it can heat the water flowing through it.
Compare vented and unvented systemsKeep the storage temperature and the outlet temperature apart in your answer. Stored water is kept hot enough to control Legionella; the temperature delivered at a bath or basin is limited separately, usually by a thermostatic mixing valve.
Revise mixing valves and scald controlExplain why a long dead leg wastes water and time, and when secondary circulation is the better design. A loop that keeps water moving must still be kept hot enough to limit bacterial growth.
Revise dead legs and secondary circulationFor a system question, identify the water supply, the heat source and the safety controls before choosing an answer. For a calculation, write down the volume or flow, the temperature rise and the units first. Use the water heat-up calculator to check your working after answering.
A hot water mock test checks recall without the explanation after each answer, so you see which ideas hold up on their own. Hot water is one unit of plumbing theory; test the other units in your course as well.
The free test offers 5, 10 or 25 questions from this same set, with an optional practice timer. In Test mode, answers and explanations appear after you finish. Repeated tests reuse this bank, so a higher score can reflect familiarity.
Set up a free Hot water systems testHot water is one of the core Level 2 plumbing units, alongside cold water, heating, sanitation and safety. Use this set to check one part of your understanding, then compare your revision plan with the units in your own qualification handbook.
It includes unvented basics: mains-pressure supply, what a drip at the tundish means and why the discharge pipe must fall. Installing unvented systems is work for a competent person with unvented training; G3 revision goes further into safety controls and discharge pipework.
Start from the energy needed: the volume, times the temperature rise, times the energy to heat one litre by one degree. Divide by the heater output for a heat-up time, and check the units at every step before comparing your answer with the calculator.
Yes. The Test setup uses 5, 10 or all 25 questions from this set. Choose an optional practice timer and review the explanations after finishing. For broader plumbing exam revision, add the cold water, heating and diagnostic sets as well.
All 25 questions on this page are free, with no account or card required. They are selected from the maintained Hot water systems question bank. Premium opens the full bank of 161 questions, more modules and Weak-Spot Review.
A free account saves the answers you give while signed in and lets you continue across devices. Without an account, this browser can remember your place for 30 days; it does not transfer earlier guest answers into an account. Signing up keeps the same free question allowance.