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HPVB’s and water spray

By: Dale Simon, Plumber

The culture of professional preventive maintenance within the old Joburg city council inspired me and I count myself very fortunate to have had such a professional no-nonsense approach to so many aspects of plumbing maintenance, during my first years within the trade.

Repairs came first and you were expected to access, report and carry out your repair properly, or boy was your life made miserable….!

I had noted over the years that leaking vacuum breakers have continued to cause damage to domestic properties. The fact is it has also created extra plumbing calls so who’s complaining….right? The final nail in the coffin and what ultimately inspired me to develop the Vac U Cap was as a result of a 200l geyser “bursting” and a very unhappy customer complaining that the resultant water damage to his home was as a result of a poor quality installation and that I was making use of inferior product.

My client had called in another registered emergency plumber, who had isolated the water and already arranged the cylinder replacement for the following morning.

Fortunately I keep files recording of all the hot water systems we have invoiced over the past six years and I was able to confirm that we had installed a new 200ℓ cylinder at the premises only the previous year!

Arriving at the Hollywood-style mansion, I was received by a very hostile client and was shocked to see the resultant water damage to his main bedroom, it literally destroyed the ceiling, floors, king-size bed, and the very expensive content of the wardrobe were completely ruined!

On locating the horizontal hot water cylinder positioned above the main bathroom, I proceeded to carry out my investigations. The geyser installation looked as per SABS0245, the hot and cold copper pipe work was neatly assembled and the PVC drip tray and outlet pipe were installed with a positive fall. I then proudly noted that the team had upgraded the installation as they had fitted a 400KPA expansion relief valve on the anti-siphon loop and a section of multilayer pipe was installed between the copper hot water outlet and the original galvanised pipe work.

The 600KPA cylinder was isolated and the hot water pipe cut through.
Locating the 400Kpa pressure control valve outside, I carried out a pressure test confirming that the PCV was in fact reducing the incoming water pressure to 340Kpa.

The hot water outlet pipe was quickly reconnected and as the pressure built up the hot water HPVB started to spray like a 360˚ irrigation pop up! The water splashed well beyond the carefully positioned drip tray and I quickly closed the water off. Trying to explain the actual fault to the client, I received the usual blank stare and I was then informed that the insurance company had already approved the cylinder replacement and that the emergency plumber had already been given the go-ahead to replace, as well as relocate the cylinder to the garage below the bathroom. I haven’t heard from this client, his family, or business, since that day and finally I realised that HPVB’s are a liability to all of us.

What started out with a one dimensional technical drawing has become 16 months of research and development, firstly a geyser testing area was set up to simulate leaking HPVB’s in a controlled environment, my drawings were handed over to an industrial designer, 3D models were grown, tested, discarded, and refined, until finally I was happy that the VUC is the best possible solution to this ongoing problem.
At first I started with only one insurance company’s statistics regarding HPVB failure rate and I was shocked that only four defective vacuum breakers were reported over the past year, of geyser-related claims, the procurement manager looked at me in total disbelief and stated that to his knowledge HPVB’s don’t ever fail and that the main reason for an increase in water damage was due to incorrect geyser installations.

Doubt set in and I realised that I needed to do my own research and the results of my plumbing questionnaire was astounding, out of the 30 plumbers who took the time to tick the blocks, 26 agreed that HPVB’s cause water damage to houses even though they are correctly fitted over the drip tray! Of the four plumbers responding, one licensed plumber then accused me of trying to ruin his second-hand geyser business!

The VUC was recently independently tested by CPT (PTY) LTD who was kindly referred to me by the SABS. 240 hours of testing at a max pressure of 600Kpa has confirmed a 30% reduction of water spray beyond the geyser tray and as the VUC is locally produced using high quality polypro, I am confident that it is reusable and will last for many years even with long-term exposure to the elements.

The Dawn group has agreed to distribute the VUC countrywide as a cost-effective solution to this ongoing problem. As part of my ongoing research I invite you, as fellow plumbers, to please email your story regarding defective SABS-approved vacuum breakers to me at

Editor’s comment
Well done Dale for taking initiative. We have a copy of the report issued and after discussing the contents with members of industry, we are satisfied that the author has acted within the bounds of SANS 10254 and 10252.

From the May 2014 issue of Plumbing Africa, page 61

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