Consumer Homes.

Question:

The Vaughn, stone lined tank in the house I purchased a few years ago has begun to leak solwly, so I probably ought to replace it before it turns my basement into a swimming pool. What is a good brand of electricly assisted solar hot water heater? Are there any better or worse out there? Tom Doggart

Response:

>The Vaughn, stone lined tank in the house I purchased a few years ago has begun >to leak solwly, so I probably ought to replace it before it turns my basement >into a swimming pool. >What is a good brand of electricly assisted solar hot water heater? >Are there any better or worse out there?

Tom, You didn’t say if you need a heat exchanger in the tank for your solar system, or how much you are willing to spend. Or if you are in an area which requires a double-wall heat exchanger. I just went through all the tank-with-exchanger options I could find. Here are some of the choices (more-or-less in order of increasing cost): Ordinary home improvement store glass-lined electric water heater with external exchanger added. Bock glass-lined tank with internal glass-coated steel exchanger. Vaughn stone-lined tank with internal finned copper exchanger. Bradford-White glass-lined tank with internal HDPE/Aluminum exchanger. Ergomax unlined steel tank with internal smooth copper exchanger, but with DHW in the exchanger coils and "dead" (oxygen-free) fluid in the tank (but this design does not allow for an internal electric assist element). Phase III flexible stainless tank inside stainless tank (again no internal electric assist). SuperStor, Mega-Stor, Burnham, Jass, SST, Amtrol, etc. stainless tank with internal stainless exchanger (some may allow internal electric assist – I was not paying attention). As you know, glass or stone lined tanks will leak eventually. So will stainless tanks. The weakness is the junctions between the various components, especially if they are different materials. An internal exchanger, being the hottest part of the unit, will attract all the minerals from your DHW and its efficiency will decrease. (The Vaughn exchanger is removable for cleaning, but the job doesn’t sound like fun.) The only standout I found is the Ergomax. The oxygenated DHW never leaves the pure copper internal exchanger coils, so the uncoated steel tank should last forever. The fluid in the tank, solar panels, and external boiler is oxygen-depleted and corrosion inhibited, and also mineral-free, so there should be no decrease in efficiency over the years. The negatives are having to fill the whole storage tank with antifreeze, and in your case, supplying a new external backup heat source. For a lower priced unit, I would probably go with the Bock. They are reasonably priced, readily available, and have a good reputation. Probably last as long as any other lined tank. Have you considered converting to gas backup heat while you’re plumbing? For under $1K you can get a Bosch or Seahorse gas copper tube heat unit…   Loren

Response:

Thanks for the inputs, The Vaughn appears to be the best for my set of circumstances. Thanks Tom

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