Pipes are easiest to check while still visible. After screeding, even minor damage is harder to locate, so pressure testing is an important acceptance stage. A photograph of a gauge showing a large number is not the whole test, however. Know what was tested, the procedure, conditions and recorded outcome. The report must also make sense to someone who was not on site.
This is not an instruction for DIY pressure testing. A competent specialist tests according to the particular system manufacturer's requirements and the design. We explain which information owners should request and why one pressure seen online cannot be applied to every product.
First record clear test boundaries
Identify the site and the specific system section. Were all circuits on the storey tested together with the manifold? Were distribution pipes and the heat source isolated? If only part was tested, make that clear. Otherwise 'the heating was tested' may wrongly include connections the test never covered.
Add branch numbers and the schematic version. If another component or distribution extension is installed later, the earlier report does not itself confirm the new section is leak-free. Assess revisions and, where needed, test and document them separately. Date the report for the actual test, not the planned completion.
Pressure and duration must not come from memory
Test procedures depend on pipe, connections, system and test medium. Reference the instructions used and record required stages. Avoid claiming every floor system merely needs pressurising to one figure for a certain time. Even similar products may have different procedures.
Uponor installation instructions explicitly mention testing before pouring and a test report. Coordinate the system principles given there with the current procedure for the particular product. Owners should simply request more than “checked” where neither figures nor a procedural basis are recorded.
Identify the test medium too
Water and compressed-gas tests are not equivalent. A compressible medium stores a different amount of energy, so air testing requires specific safety precautions and a manufacturer-permitted procedure. The Uponor Q&E FAQ emphasises a competent specialist and a separate safe pneumatic test regime. This product explanation must not be treated as permission to test any floor pipework with air without proper arrangements.
If water remains in the system during winter, discuss freezing risk. A successful test does not protect pipe against later freezing in an unheated building. The responsible specialist must specify a solution for the particular materials and heat source. Adding a random fluid yourself is not suitable protection.
Temperature helps explain pressure changes
Record ambient and medium temperatures and their changes. Pipe material behaviour and temperature changes may affect gauge readings. Every small change is not automatic proof of a leak, but cannot automatically be dismissed as temperature either without the procedure and inspection.
Distinguish preparation, stabilisation and assessment stages where the instructions require them. If a specialist restarts timing after topping up, record that. Otherwise it is hard to establish whether pressure held for the specified duration or was simply raised again before the photograph.
The measuring instrument is not an insignificant detail
The report identifies the measuring instrument and its identification details according to the applicable procedure. Its scale must allow a sound assessment of the change required by that procedure. A photograph of a coarse-scale instrument should not be presented as evidence of accuracy for very small differences. Being able to see a reading and having a suitable measurement are different things.
A photograph is useful supplementary evidence if it shows time, system section or other clear context. It does not replace a table of starting and finishing values. A simple completed report with clear figures is better than many similar photographs from which the test sequence cannot be established.
What should a pipework inspection check?
The specialist inspects visible connections and pipe condition. Testing does not remove the need to assess kinks, scratches or unsuitable fixing. Some installation defects need not immediately cause an obvious leak. Manufacturer criteria determine acceptability, not the gauge reading alone.
If a defect is found during testing, record its location and repair. Perform the necessary repeat checks afterwards. Do not document only the first test start and hide subsequent repairs. The final result must represent the actual system about to be covered, including all changes.
What should the report cover?
| Record section | What it allows you to verify |
|---|---|
| Site and circuit list | Which section was actually tested |
| Procedure and medium | The conditions under which testing took place |
| Pressures, times and temperatures | What was recorded at each stage |
| Inspection and repair records | Whether identified defects were resolved |
| Outcome and responsible person | Who confirms the specific conclusion |
Also agree the system's state during and after screeding. Assign someone responsibility for pipe protection: it must be clear who monitors work and what happens if damage is noticed. After covering, keep documents and photographs with the circuit schematic.
What does this test not prove?
Leak-tightness does not confirm heating output or balanced flows. These need separate commissioning and performance assessment. Nor does the test establish that the floor layer is dry enough for its finish. Confusing these stages leaves important gaps even when 'checked' looks convincing on paper.
Before accepting work, review the general underfloor heating guide. If you have only one gauge photograph, request the missing explanation rather than guessing test conditions. A clear report protects both parties practically: the owner knows what is accepted and the contractor can demonstrate the checks actually performed.
Information sources
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