Maintenance, Repair and Leak Detection
What this domain tests
Maintenance, Repair and Leak Detection tests preventive maintenance, fault diagnosis, leak location and safe repair. Expect practical scenarios: a dripping joint, a running cistern, a damp wall, or a water meter that moves with all taps closed.
Core rules
- Preventive maintenance includes inspecting supports, valves, insulation, traps and tank levels before failure.
- Isolate and drain before repair; prove isolation by opening a downstream tap.
- Leak detection starts with history and visual inspection, then a meter test, dye test, pressure test or acoustic listening.
- A meter test: close all fixtures and the main inlet, record the meter, wait, and check for movement; movement indicates a leak on the live side.
- Repair methods must match material: compression for copper, push-fit for compatible plastic, solvent weld for uPVC/CPVC, soldering for copper.
- After repair, flush, test at working pressure and check for weep.
Worked example
A water meter still moves after every tap and cistern is closed. The reasoning is that water is passing somewhere downstream of the meter. Isolate the internal stop valve: if the meter stops, the leak is inside; if it continues, the leak is between meter and stop valve. Then use acoustic listening or a dye test on suspect WCs.
Traps
Over-tightening plastic nuts, using tape on a compression olive, repairing a pressurised joint without isolation, and assuming a damp patch is always a supply leak are common errors.