rrnut-2 wrote: ↑
Mon Feb 05, 2018 2:38 pm
There should be thermostats in the furnace drain lines that are set for a maximum of 185 degs. Don't want to destroy things. The silicone would be more forgiving of small amounts of molten metal hitting them. We covered the hoses on the outside of the furnace shells with silicone covers. The nylabrade worked pretty good, with the next step being non-conductive hose from Inductotherm. The furnace leads used the Inductotherm hose.
Take note of the large array of lights/switches on the left hand side of the unit. A pressure switch (which I have shunted for testing) doesn't permit the unit to run if pressure is low, and there's temperature sensors for water and bearings that shut off power if there is overheating. Temperature is set for 190° by default (according to the manual).
Return temperature of cooling water can be determined for each section, as each discharges (individually) to atmosphere on the right hand side of the unit. I'd have to enclose that part if I end up with a closed system, which shouldn't be much of a chore.
I'd like to explore hose options. The Nylobrade appears to be the most economical, but I question the long term life expectancy. Do you have an idea of how long it might serve? It's not real convenient to replace, so it might be a false economy.
In regards to power leads, unfortunately, I have only one, so I will have to buy or make new ones in any case. I was fortunate to find one coiled up inside the power supply. What happened to the other three is anyone's guess, but they, like the legs for the furnace, got separated long before I got involved.
I may be able to make two leads from the one I have. It's much longer than I need, and must undergo repairs, as the connection has been crushed, as if run over by a lift truck. If so, that still leaves me with the need for two more. Fortunately, Ajax provided prints for the leads, so I have a sense of direction.
Your thoughts on the following, please.
A containment pit is suggested, one that could absorb a failed furnace. Volume, in my case, is small, so I have considered a rectangular platform built of concrete block, within which one could put sand. The furnace would mount on top of the platform, an 8" rise.
The shop floor is reinforced concrete, and is 6¼" thick. Rebar, to which my hydronic heating is attached, is on 18" centers, and is in the bottom 2" of the concrete. I suspect I'd want as much distance between the rebar and leads as I can get. I also suspect that so long as the leads run parallel to one another, there is an effective cancelation of induction.
I certainly don't want any molten metal to come in contact with the concrete floor (explosion due to steam), so I expect I'd have to work over a bed of sand where I'd cast.
Of interest, the original legs were made of Jessop steel (austenitic). The furnace Jim provided has legs that are magnetic. I now question how important it would be to use austenitic steel in case I have to end up using the original furnace?