Okay, I guess it is too wordy. I always think of alternative plans as I go along..

I got leery of using the old steel oil-fired boiler.. It's super old and could start leaking,
and we would be without any source of hotwater.

So, the safe route is to use a new tank and install/use the A7 the way it was intended.

It should look somewhat like this, when I'm done..

http://images.lowes.com/product/conv...52003003xl.jpg

Here's a pic of someone's install before inserting the HX loop.
http://knoji.com/images/user/airtap-install.jpg

i really like this idea, though in most cases i cant really see its benefits. im anxious to hear how this work out for you though. sounds like it should reduce your oil usage.

That's the new version. It's ~5% more efficient based on the yellow Energy Star tag. I'll happily take that slight loss for half the price.

I'm DIY all the way on this. I had to clear a bunch of space in the crawl space to fit the plumbing. (new location is an add-on so there was a cement wall in the way) Now to start actually running pipes.

Xringer, correct me if I'm wrong, but don't the A7 directions say to disconnect the regular heating elements?

Does your boiler have sacrificial anodes to prevent corrosion?

I don't think so. It says disconnect the WH power during install.

On the Ebay page, it says "For maximum savings, it is recommended that the existing water heater be disconnected."

But, using the heating elements might be required if you have company and a few more folks need to take showers.. :)

Seems like you could set the A7 to 125F and set the heaters to 110F..
When the A7 wasn't keeping up with demand, you pay extra.. :)

There is a port on top where the Anode screws in. I'm assuming it's there.
Maybe I'll pry off the plastic cap, cut out the insulation and remove the Anode for inspection.
I think it might need to be well grounded to the tank, so maybe Teflon tape might not be the best way to re-install it..?.

The A7 brackets attach to the water in/out pipes (nipples).

I've already pulled the hot & cold nipple (PITB). I will replace the hot with the special brass nipple from the A7 kit.

The cold nipple is short and has flow restriction (small check-valve), so I'm going to replace that one with a 6" iron nipple.

Using the short (stock) cold water nipple causes the U-bolt clamp to rest
on the connecting cold water input pipe..
http://i46.photobucket.com/albums/f1...DHW/ironip.jpg
Since I'm going to use 3/4" Pex, the extra tall nipple will allow the clamp to rest on iron. (It can be real tight).

Here's my test fit photo.
http://i46.photobucket.com/albums/f1.../nBrackets.jpg

Notes on nipple removal
 

Note on nipple removal. In the reviews, I found out that some GE factory nipples leaked, causing product returns.
(Some folks found it very difficult to remove factory nipples).
The A7 requires the hot water nipple to be replaced with the special brass T-nipple included in the kit.


My goal was removing both for them. The cold nipple came right out with the pipe wrench.
But, the hot side was stuck solid. I added a 26" extension handle to the wrench. (1" heavy aluminum tube)
But the whole heater turned when I applied force.. :(

So, I placed a 4 foot aluminum tube on top of the heater, laying it in between the cold nipple and the T&P valve. (on it's smooth side).
That allowed me to pull the two aluminum handles together (like scissors), and remove the stuck nipple.

http://i46.photobucket.com/albums/f1...W/niptrick.jpg

Why would you use an iron cold line nipple, with the dissimilar metals problem? A ¾ x 6” brass nipple is only about $5.

My propane fired DHW is also used, with internal HX, for in-floor radiant system. Therefore my plan is to use an outside thermostat to control the gas fired system. Fire the propane system when outside temp is below set point and in-floor system is calling for heat. This in addition to your idea of setting the A7 to 125F and set the heater to 110F.

anode hex exposed
 

I popped the anode cap and cut away the foam. There is a hex-head on the tank.
It looks like it's about 1 & 1/16" (1.0625") across. Not a size that I own.. :(

My guess is a 1" socket from Sears will do the trick..
1 in. Socket, 6 pt.- Craftsman-Tools-Mechanics & Auto Tools-Sockets


1" was too small.. :mad:
Went back, pay another buck and got the 1" & 1/16" socket!
1-1/16 in. Easy-To-Read Socket, 6 pt. STD, 1/2 in. drive- Craftsman-Tools-Mechanics & Auto Tools-Sockets
and it worked fine!!

Or you could just ask GE what, if any, their anode system is, life expectancy, and replacement cost. You did buy a glass lined tank, did you not?