I have attached a photograph of a cylinder that recently failed in propery I am managing.
The cylinder has completely failed at approx "10 Oclock" leaking steam and water, cylinder installed 06/2003.
Property probably on irrigation water and anode never changed.
An expensive failure probably due to hard water and no maintence.
I would be interested in any info you may have on water pretreatment to prevent an early failure in the replacement just fitted.
Thanks "G"
______________________________
Gary responds:
On a recent cycle tour of Vanuatu I saw one after another of this design rusting away on rooftops. They were everywhere. Scandalous that this continues despite all of the adverse publicity.
I am particularly disappointed with EECA and the Consumer's Institute. Both of these organisations are well aware of the problems for some years and have even inspected the rusting panels that were once on my own roof top. Yet, they continue to enthusiastically promote this technology without giving the consumer any real advice about how to differentiate between the trashy systems and the quality ones.
The photo of the Solahart is revealing:
- There is no lagging of the pipes which would result in huge heat loss particularly at night and during winter. It would be interesting to see the state of the lagging on the pipes to and from the house appliances.
- Copper overflow pipe outlet is directly onto the roof iron. This will cause galvanic corrosion of the roof.
- You can see hints of roof iron corrosion surrounding the system. SWH systems need to be galvanically isolated. It appears this is not.
- You can see that the panels themselves are corroded white and there are signs of condensation. These should be black - not white and inside and outside of the glass clean.
Quite obviously, this SWH unit is unsuited for the job and the owner should have a warranty claim for replacement. Warranty is about 5 years in most cases; but there is the promise that these will perform without trouble for at least 10 years with their ROI anywhere from 10-20 years.
"G"; the Solahart you have here is only good for the landfill. The entire system needs to be replaced.
Only replace it with a system that is closed glycol circulation with a heat exchange unit. Solar water heating systems that are not closed circulation should be banned. They scale up quickly and rust out.
It is just plain nuts to place a hot cylinder on the roof of a building. It is the worst place for heat loss and corrosion.
The problem you have in throwing out the current SWH system, as many owners have discovered to their dismay and horror, is they face thousands of dollars relocating the hot water cylinder and re-routing plumbing. Some houses do not have alternative space for the cylinder.
Have a look around - There are good systems out there. Do not go for the cheapest. Go for an established brand and buy quality. Do not skimp on any part.
I have an AMK on my roof and it has performed two years without a hitch. However the NZ agents have gone broke! I have no idea what to do other than hope we do not need repairs for several years.
The best system so far, in terms of quality and absence of consumer complaints is Chromagen.
