With the 3D design to guide me, I set about building the pump/filtration system and connecting all of the suction and return pipes.
Model vs reality
Before access to all of the pipes and fittings is lost under a mountain of dirt and concrete, it is imperative to test the system for leaks. It would be a disaster to put in the concrete footings, walls, bond beam and paving, and then discover that the plumbing has a leak somewhere.
Pressure testing can be done with water or air, but using water is inherently safer due to air being highly compressible. For example, if we take two litres of air at atmospheric pressure and double the pressure, the volume will halve to one litre. At this point the air is like a giant spring, wanting to expand again and only being stopped by the vessel containing it. If that vessel fails, the rapidly expanding air will turn that failed piece into a projectile (or more likely many projectiles). This is why people use air to make PVC cannons.
In principal pressure testing is quite simple:
- Seal all of the holes in the system (e.g. skimmer, drains, returns).
- Fill the system with water and increase the pressure to somewhere above the maximum expected operating pressure.
- Monitor the pressure over 24 hours and if it falls, you know water is leaking somewhere.
With the right equipment, the practice is also quite simple. Unfortunately I have no equipment and buying a dedicated pressure testing setup for one time use is a no go. So once again I had to build my own.
It's pretty straight forward. I'm using a garden hose to "charge" the system, and then sealing it via the installed tap. A gauge then shows the pressure within the system. Below is the tester installed to test the pipework to the return eyeballs.
Ideally the entire system would be tested together, but various factors prevent that. Since the crucial elements are the pipes and connections that will be underground (particularly those that will be covered in concrete), those are the ones that were tested thoroughly.
Over the course of a couple of days, I was able to satisfy myself that there were no leaks in any of the pipework/fittings.