rrnut-2 wrote: ↑Sun Feb 04, 2018 5:30 pm
Harold, I believe that furnace was made by Ajax, The induction power supply that it was hooked to was an Ajax and the company tended to buy the parts directly from the OEM.
If the coil supports and the method of mounting are an indication, yeah, it looks like it's Ajax.
They used two different methods to supply water. With the old unit I'm working on, there's two hoses for each side of the coil. Water is under pressure in one set, and the return is the other. They did this because the coil is a twin, two coils wound in one. I expect it was to shorten the path for the water, but that may not be the case. At any rate, I have to use two leads for each side, whether I use the original furnace, or the one you provided.
I made a decision to restore the original, which I don't regret, but I'm not going to put it in service at this time. As soon as I reassemble it, I'm going to start on the donor that you provided. Power for that furnace, which appears to be a 100 pound coil (mine is a 50), is provided by one set of leads only. Water is provided for each lead, but the coil is tapped in the center, where water connects to a common hose for return. I'll plug the center taps and add two copper manifolds so I can connect the twin leads. I like that the donor has a tilt system and is complete, although in bad need of rebuilding. That takes time, as you know, but it's not a big deal. I've learned a great deal about them in working on the original, and I'll make a post in the future, including a few pictures, to show what is entailed in restoring an old furnace.
A closed water system would be good. Just make sure the antifreeze isn't conductive at whatever your furnace voltage is. Same goes with hoses, I learned that the hard way. So if the furnace voltage is 3000volts, then all of the rest of the components need to be able to withstand that...and yes the liquids are one of the components.
Sigh! Wish I'd have given hoses some thought before I jumped. I made a call to verify that the hose needed would withstand antifreeze, so the guy I talked with (not at Ajax) suggested that I use heater hose (automotive). Took about 75 feet to replace all of it, half of which was quite hard and cracked. Only after it was installed did I consider conductivity and was shocked to find it had relatively low resistance. Much too low to be used, as it would leak to ground, something I'd like to avoid. I'll now have to start over with the hose. By the way, this power supply puts out a maximum of 400 volts, so it's not as bad as larger units. The high frequency transformer offers eight different voltages, down to around 200 volts, if memory serves.
Nylabraid hose works good, but you will have to retighen the clamps every so often.
Not familiar with Nylabraid. Is there a preferred place to buy, or should I just buy from Ajax (who has suddenly become silent---as if they don't want to be involved with this project)?
And speaking of hose clamps, make sure the ones that you use around the furnace are completely Stainless Steel. A lot of the worm clamps are SS on the outside, but the worm is regular steel. This will just ruin your day.
Oh, yeah! I've experienced such clamps. Can't take that risk with an induction unit.
The clamps that came with the unit are in perfect condition, aside from being dirty. Bead blasting restored them to like new condition. I don't know that they had ever been removed. The hoses were fused to the barbs and had to be cut away, with the barbs bead blasted to remove the traces of hose that didn't crumble off by abrading. I have reused them and they appear to hold well. I flushed the entire unit (minus the capacitors, which are new) to remove deposits, and test for leaks. I found none. The high frequency transformer was removed, and given extra attention, as it has poor flow when in good shape, and was almost completely plugged. I talked with the makers and was given some guidance. It appears I dodged a bullet, as the unit sat out of doors for at least two years and went through several freeze/thaw cycles. The original caps had frozen, but they resided in the bottom portion, where they couldn't drain. The transformer was higher, although ported at the top. For what ever reason, it didn't get damaged. The maker said it would "leak like a sieve" if it was damaged. It held 100%.
Thanks for your comments, Jim.
H