Electronic Drive repair service

One of ours is wired to the lower element of the domestic water heater.

DAT is effing brilliant!!! Green indeed!!

There's gotta be a ng award for this one!

Nice start, nice germ of an idea, but you have to carry the idea through to it's logical conclusion.

One big problem, you need the lower element to heat up the water in the bottom half of the hot water tank normally - it's not going to have any useful capacity without it. 5 gallons and Pfft! cold water.

Now if you want to really be green about it, you put a smaller electric water heater (12-gallon plus) as the load resistor, and plumb it up as the pre-heater on the Cold Inlet to the big water heater.

If you have a whole room full of machines, you can rig up a circulating loop that makes a lap of the entire shop, with a tee-fitting to screw in each machine's load heating element - the standard screw-in elements have 1" NPT threads, you want 1-1/2" pipe for the element chamber so it doesn't touch the sides. Has to have water flowing all around or hot spots will cause failure.

I'd use a 1-1/2-1-1/2-1/2 reducing tee, 1-1/2" x 1" Ftg X F bushing for the element, and an 1-1/2" X 1/2" reducing coupling. Mueller makes all of the above, I just looked.

A small wet-rotor pump to circulate water through the loop, and loop it back through the pre-heater tank - and the pump needs a vane-style flow switch to monitor for pump failure and sound the alarm if the water isn't flowing. If the water in the loop stops, you'll start boiling water and slagging heating elements real fast.

If the machines are starting and stopping enough to give the load resistor system a workout, you can be washing hands, running loads of shop towels through the clothes washer and running the dishwasher in the break room without the electric water heater coming on more than a few minutes.

And if the hot water isn't getting used enough... I STRONGLY suggest an over-temp alarm on the pre-heat system tank set to sound at about

160-F (Use Some Hot Water! Run a wash load of towels! Give the Shop Dog his weekly bath!) and the standard 185/190-F Temperature/Pressure relief valve plumbed to dump in a sink or to a safe place outside.

That means not dumping right where all the workers gather for their smoke breaks - a near-boiling shower could really ruin their day.

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Its a 30 gallon tank and yes the regen only preheats the bottom , but since we only use hot water to wash our hands the lack of capacity is not a problem.

I've used old water heater tanks for alternate energy projects, and found that the screw-in elements have straight threads and seal at the square O ring. It looks like 1-1/4 -- 11-1/2 which is the same pitch as 1" NPT and fits at the larger end of the taper.

jsw

I've been trying to find a threaded adapter (not flanged) for a friend that wants to use inexpensive, common water heater elements with old cast iron heat radiators.

If you know of any 1" straight female thread to NPT adapters that are available, I'd appreciate you mentioning a source.

The one time I used a water heater element in a 1" NPT fitting I just used a bunch of Teflon tape on the threads and it sealed up okay.

I suppose if you are making adapter fittings in bulk you could chuck the bushings up in a lathe and cut the square recess for the sealing ring. The difference between the fat end of NPT and NPST threads should be more than close enough to hold.

Oh, and Silver Braze the fittings around the heater element - if you have a water circulation failure, the melting temperature difference between ''Plumbers Lead Free Solder" (usually a 0.5% silver solder) and silver braze could make all the difference.

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I would've assumed few problems with the method you suggesed Bruce, but the friend has has every installation leak.

Thanks for your additional input.

He's atempting to use common cooking oil, although I've been saying that most mineral oils (same cost) would probably be fewer problems with pipe dopes.

I just rcently realized that I could chase the NPT threads with a straight NPSM tap to allow full seating of the element threads.

I was trying to come up with a solution where I wouldn't need to source stock and machine custom fitings. However, the home brewing industry could benefit from an inexpensive fitting, too.

I don't have a 1" NPT die handy. This is based on an old element screwed into a galvanized coupler.

The element stops finger-tight in 1/4 turn, so I think a die could recut the element's threads from NPSM to NPT, though it will remove any protective plating such as this element has. You might have to grind down the face of the die or use an adjustable one.

I've modified some solid brass Sears element heads after knocking out the burned-out heater. Even without its interference they are quite difficult to center and align to pick up the threads. If I was going to do very many I would thread the ID of a tube to fit snugly, turn the OD concentric, and use it along with a pipe center in the tailstock to square and center the element head in a 3-jaw Set-Tru chuck. I don't trust my 4-jaw to hold a hex securely enough, the two points crush and slip.

If you tap the opening NPSM you still need a smooth recess for the O ring. They won't hold much pressure if just squished against a flat face. Perhaps a copper gasket cut from water pipe would work???

I had the opposite problem of sealing pipe-threaded reducer bushings in the tank opening. Some worked with a thick layer of tape, others didn't, depending on manufacturing tolerances. I chucked some pipe and screwed the reducer bushing on to it to cut the groove for a square O ring.

jsw

We had contemplated a copper seal after getting the threading hashed out to have a secure assembly.

A straight tap could open the door to other possibilities, too.. using a cast brass coupler with room for a groove for the sqaure seal ring, for example.

Several prototypes had been made, alhough all had leakage problems. I tried to stay out of the process, but at the same time, realized that the idea shouldn't be too complex.

I think I've found some straight taps (won't know positively 'till I have 'em in hand) on eBay, fairly cheap.. my offer was $30 for 2 taps. When asked, the seller stated that the thread pitch is 11-1/2.

I'd expect that a copper crush gasket would work, or your suggestion of turning a recess for the rubber gasket on the lathe.