Author Topic: Resurrection of a CFEI 100 KVA Induction Furnace  (Read 65354 times)

Offline awemawson

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #850 on: February 27, 2023, 04:43:14 AM »
Text from DHL saying the Glycol will be here after lunch so time to rig up a pressure test on the heat exchanger.

Encouragingly the catch pot had caught quite a lot over night which I think implies that the drips are just coolant on the plates held by capillary attraction and slowly falling lower - or is that wishful thinking !

So, firstly - open up one side of the coolant loop and find something to adapt from the 28 mm / 1" compression fitting to the 1/2" BSP output of my pressure test pump. The 'It'll come in handy box' furnished the needed bits.

Then opening the ball cock on the input side of the heat exchanger I pumped a fair volume of water, hoping to as far as possible force the air out and water in. Then, closing the ball cock I pumped the test pressure up to 200 PSI (system normally runs at 50 PSI) and will leave it for at least an hour to see if it holds, but so far so good.
« Last Edit: February 27, 2023, 10:57:05 AM by awemawson »
Andrew Mawson
East Sussex

Offline awemawson

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #851 on: February 27, 2023, 10:36:50 AM »
After an hour and three quarters the pressure hadn't altered one jot so I put the plumbing back together and started a 'tap water flush' involving filling the tank from buckets until above the pump input, running for a while, then "aqua-vaccing" it all out. The tank is not the easiest of things to pour a three gallon bucket into. I did three cycles of this purging with tap water until things ran reasonably clear.

As I was finishing the last flush the glycol arrived - perfect timing. I started off putting in 25 litres of de-ionised water and 25 litres of  glycol and measured the freezing point with the refractometer - minus 40 C IIRC. I was aiming for -15 degrees so added a further 25 litres of water giving me -10 as a freezing point. As the level of the coolant was now almost covering the return pipe (want it covered to avoid frothing) I added glycol until the return was well covered, then titrated with demin water until I got my -15 freezing point.

All a lot of fussing about but at least it's now done and any doubts about the integrity of the heat exchanger are dispelled.

I have a cheap Chinese water resistivity meter on order - apparently the coolant needs a bit of conductivity but not too much and I still have room in the tank for a few more litres of fluid if things need tweeking.

Andrew Mawson
East Sussex

Offline tom osselton

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #852 on: February 27, 2023, 05:53:05 PM »
Iíll get the popcorn!  :beer: