Magmas Chromalox PID controller

[hunter74]

I have just put 4 new heating elements in my Bullet Master and thanged out both of the thermocouples. For the first run they melted lead like newer before, and I was very happy.

The seccond day the pouring side of the pot didn't keep up with running 180 gr RNFP. Something was clearly wrong. Turned the machine off to go over my wiring and it turned out that one of the leads for one of elements were loose, on the pouring side. Connected that again and the problem was still the same.

I then measured the voltage inn on the Chromalox unit on the pouring side. Inn on the unit it was 230v but out it was 0 so there's no juice going out to two of the elements. (See pic) The other unit has 230v both inn and out and it's getting hot on the premelt side, so everything is OK there I guess.

Before getting an answer from Magma on Monday maybe anyone of you know if it could be something else than the Chromalox unit. Does it have a built in fuse or is it dead and has to be replaced with a new one? Does anyone know the cost?

Thanks!


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[hunter74]

Looks like the Chromalox unit is shorted or something, since the voltage is not flowing through.

Since Magma no longer sells these I guess ebay is my best choice. It's either that or changing the the whole control box with all the works and new wiring. That would set me back 1k USD's...... I'll try ebay for now...

Or.... Anyone have the 230VAC version laying around, and willing to sell it to me?

Thanks

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[hunter74]

So I got one from flea bay...... And the problems continues.... Now it's getting too hot!

Got the new to me Chromalox installed and as I can see wired as the old unit.

Now both sides of the pot (all elements) are running at full blast all the time so now its getting way to hot. I doesn't matter how low i set the set temp but the element does not cut, and run at full tilt and maxes out around 900. The displays also shows about 50 f below actual temp but that's no hassel at this point.


Any idea of what could be wrong? Anyway its strange both Chromalox units acting up at the same time..... The one working right before is also behaving in the same way.....
Attaching pic of the wiring. Looks right doesn't it?



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[Hootmix]

Hey hunter just looked at your pics,,,,,your TC wires could be wrong,,,,pic 1(at top) shows the red TC hooked to #8 and wht. to #7,,,in photo #2(bottom) they are reversed,,,my MKII caused me some of the same problems,,,pulled out the old ones installed new ones ,,now everything good to go ,,TC are usually the main problem( ask me how I know ??? HATCH told me ),,give it a look .

coffee's ready,,,,Hootmix.

[hunter74]

Hey! I've just installed two new thermocouple wires and didn't notice how they were wired because I thought it didn't matter! Guess it does! Thanx!

I had 50% chance of doing it right, strange I managet to get them both wrong! Guess I thought red was +🤣

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[Hootmix]

hunter if the TC wires are not tight and making good connections,,,,,unit won't work right,,ask me how I know( lol). Hope it works for you.

coffee's ready,,,,Hootmix.

[HATCH]

If you switch the wires around on the TC, your temp will go down when it gets hot.
Basically you will get a runaway situation.

PID thinks temp is cold so it runs heater to heat it up.
The hotter it gets the colder it is reading.

[HATCH]

One more thing.

I am not familiar with that unit without looking up the manual but it is possible that your replacement PID is configured for a different type of TC

I normally use K type. But Magma uses J type on the Master Caster.
I know that using a J type when the PID is set for K type will cause your temp to read higher the. Actual temp.

[hunter74]

Hatch, sounds right. A runnaway pot is what I have at the moment.

Magma confirmed that I've reversed the wiring. If I change over the red and white lead it should work according to them. The white is +.

Regarding the thermocouples, they are of the right type for the unit I have. The 04 digits states J type 0-999F and also confirmed by Magma, so I'm crossing my fingers and toes until I get the pot fired up again, after swapping the leads.

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[Smoke4320]

Keep us informed ...

[Hootmix]

Hey hunter,,,,,,we really "want to know".

coffee's ready ,,,,Hootmix.

[hunter74]

Hey,,,, I've been caught up on my real job so I haven't been able to try it out yet but yesterday I swapped the leads around and just turned the pot on for a few minutes. It looked like the thermostat kicked in and went off a coupple of times, so it's looking promising.......

Today I'll fire it up and se if I can get the units adjusted to behave the way I want. I'll post more info when I know. The pot is heating up right now.......

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[hunter74]

Yep, the machine ran for an hour and the temp settles at set temp and holds it the way its supposed to do. That made my day for sure!

But if anyone has an extra Chromalox unit I'll be interested in buying it. Magma no longer sells these and has changed the wiring a bit so it could be cool to have a spare one in house. I need the -204 version. The 2 digit says it's the 230V version and 04 it's J type thermocouple 0-999F.

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[HATCH]

whats the model # of the unit you have.

Typically most PIDs are standard sizes.
Like 1/16 DIN

here is a common size list
spec cutout size
1/4 DIN 3.64" x 3.64" [92 mm x 92 mm]
1/8 DIN 3.64" x 1.78" [92 mm x 45 mm]
1/16 DIN 1.78" x 1.78" [45 mm x 45 mm]
1/32 DIN 0.874" x 1.77" [22.5 mm x 45 mm]

Its looks like a 1/4 DIN

If it gave you any more trouble, you can buy a replacement here -> https://www.auberins.com/index.php?m...roducts_id=102
Get part # SYL-4352
You will need to get a SSR

Based on the picture you posed it looks like you have a side wall near the PID.
Get a 40 amp SSR -> https://www.auberins.com/index.php?m...products_id=30
Get a heat sink -> https://www.auberins.com/index.php?m...roducts_id=348
Get thermal paste -> https://www.auberins.com/index.php?m...roducts_id=563

The heat sink I picked out mounts on the OUTSIDE of the enclosure.
Its low profile.
You would mount the SSR so the load side wiring is near where the output relay wires are.
You would then run a pair of 18 ga wires from control side SSR to the output terminals on the new PID

Put the thermal past between the SSR and the enclosure and then between the heat sink and enclosure.

Its pretty easy.
You will find out the newer PIDs are much better then the older ones as far as function goes.

You should be able to do the conversion for under $100
After the conversion, you could use any 1/4 size PIDs

Alternately, you can Google 1/4 to x/x din adapters and get a smaller more common size PID

[Hootmix]

Hey hunter,,, glad to hear y'a got'r to go'n.


coffee's ready,,,,Hootmix.