Oct. 15, 2026
A pressure test costs an hour. A leak discovered after the screed has been poured costs the screed, the floor finish, the schedule and the client's confidence. This is not a routine step at the end of a job — it is the single point at which a defect is still inexpensive to fix.
Timing is the whole point
The sequence matters more than the method:
Pipe installed and visually inspected;
All connections complete and mechanically correct;
Pressure test carried out and held;
Only then: screed, plaster, floor finish.
Once the pipe is embedded, every subsequent step is remedial work. Test before the pipe disappears.
Preparation: where tests actually go wrong
The pipe must be clean — swarf and debris left inside can damage seals or block a circuit.
All joints must be complete and correctly made. A test does not validate a joint that was never tightened.
The manifold must be isolated so the pipework can be pressurised independently of the heat source.
The pressure source must be independent, and the gauge must be fit for purpose.
The system must be vented. This is the most commonly skipped step and the most damaging to test reliability.
Why air ruins a pressure test
Trapped air is compressible, water is not. A circuit holding a pocket of air will show pressure changes that have nothing to do with leakage: the air expands and contracts far more than the water for the same temperature change. The result is either a false alarm (a pressure drop that looks like a leak) or, worse, a masked leak (a real loss hidden inside a pressure rise caused by warming).
Vent every circuit properly before you begin, and record the ambient temperature at the time of the test. If the ambient temperature moves significantly during the hold period, expect the gauge to move with it — and interpret accordingly.
Test at the pressure and duration the standard requires
Resist the temptation to improvise. The correct test pressure and hold period are defined by the applicable project standard and by the pipe manufacturer's installation instructions — they are not a number to be guessed or increased "to be safe". Over-pressurising does not make a test more conclusive; it risks damaging fittings and creating the very defect you were trying to detect.
Read the requirement from the standard and the manufacturer's documentation, and follow it exactly.
Sectional testing: find the fault in minutes, not days
On a system with multiple circuits, testing the whole installation as one volume tells you only that something is wrong. Testing circuit by circuit through the manifold tells you which circuit — before the screed exists to hide it.
This is where manifold design earns its keep. RITABLE's manifold documentation https://www.ritablepipe.com/pe-xa-series-pipe/describes the four functions a manifold must perform: distribution, control, balancing and monitoring. Isolation and per-circuit access are what make a sectional test possible.
What to record — and why it matters later
A pressure test that is not documented did not happen. Record:
That record is what stands between you and a disputed defect two years later. The same documentation discipline applies to the technical data supplied with the materials — pipe standard, certification and installation instructions. RITABLE PE-Xa pipe is manufactured to ISO 15875 alongside ASTM 876, and the PE-Xa range is supplied with full technical documentation.
Six mistakes that cause failures later
Testing after the screed. The defect is found, but only after it has become expensive.
Leaving air in the circuits. Produces false alarms and masks real leaks.
Increasing the pressure beyond the specified value. Damages fittings rather than proving anything.
Ignoring temperature effects. Interpreting normal thermal gauge movement as a leak, or a real leak as thermal movement.
Re-using a suspect component. If a joint or fitting is under suspicion, replace it. Re-testing it only tells you it holds pressure today.
No written record. No evidence, and no protection.
After a successful test
If the procedure allows, keep the system under pressure while the screeding is carried out. A gauge that falls during screeding is the earliest possible warning that the pipe was damaged by the screeding works — while there is still a chance to act on it. Protect the pipe during the pour, and never rely on the earlier test to cover damage inflicted afterwards.
Commissioning does not end at the pressure test
A passed pressure test proves the system is tight. It does not prove it is balanced. Complete the commissioning by:
Venting every circuit through the manifold air vents;
Balancing flows circuit by circuit using the manifold flow meters;
Confirming the floor heating module and accessories are correctly fixed and the pipe is protected at every change of direction;
Recording flow and temperature per circuit, and setting the controls;
Confirming the connection system used matches the pipe — see the fittings range for the four families available for PE-XA.
