Dielectric union (going where no DE union has gone before)

[Turbogus]

Hello all,
A couple of years ago we bought our first home. Some appliances were replaced as per agreement, one of which the water heater. This water heater (GE I belive) has a female copper output (3/4" thread) threaded directly into the male threaded galvanized hot water supply line. As I recall when we were looking at houses we didn't see a one with a DE union, planned failure?
Reading some 'for dummies' kind of books there are always mentioning DE unions.
So, since none of the plumbing stores not Home Depot has these M/F 3/4" DE unions am I going to have to adapt with 3/4 nipples or something?
Any info or drawings/diagrams would be very helpful as I'm a plumbing novice.

Thanks and a lift of the lynch lid for any responses.

Gus

[akaothermick]

Dielectric unions as you have read are to prevent electrolysis between dissimilar metals, as they insulate the two and provide no contact, The principle is sound but as practice it rarely happens to a major degree that it becomes a problem in a plumbing system, i have removed systems that had no DE unions and electrolysis seems to be slight if not at all. The unions themselves have been more of a problem as the plastic and rubber insulators deteriorate and start leaking. So if you water quality is soft I would fore go them as just less of a headache to deal with, but as always your local plumbing code takes precedence. Dielectric nipples in the hot water tank openings will provide leak proof electrolysis prevention.

[Turbogus]

Thanks Mick, we're on city water (Albany, OR) rather than a well (in this area if we did we've got mostly topsoil, terra cotta, then hardpan). After removal of the old water heater (20 years old +) and after the new one was installed we've had issues with what I suspect is either rust from the old WH in the feed lines or deteriation of the gavlanived pipe as this place was built in '68. Also we've got a hot water flow issue at the kitchen sink. Tried turning the shut off valves below the sink several times to dislodge and crud but the low flow persists. I sure hope this isn't indicitave of something major.

[akaothermick]

You have bigger problems than the DE issue if you have galvanized piping, it should all be replaced as it probably corroded inside and plugging up your aerators on the faucets, is the water yellowish when viewed in a clear glass? the galvanized still in use is long past its useful life, expect it to start leaking at the threaded joints into the fittings, My advice is to think about its replacement soon using a user friendly PEX system of piping that a competent home owner can actually do himself. Copper is the best but its requires skill that most home owners would have to develop, and the added fire hazard of the soldering can be avoided with PEX piping, research PEX, its is readily avaiable in most Home stores

[Turbogus]

Yeah, I was afraid of this. Mostly the discoloration is brownish when the pipes were being worked on when the new WH was installed, I also notice this kind of turbidity when we drain the WH periodically.