Seal Dry Mount Press Overheating

Alex Hawley · Oct 12, 2008

I recently bought a Seal 160M dry mount press on that auction site. The press is relatively new but the darn thing overheats. I've replace the thermostat with a new one but it hasn't fixed the problem. The amber heating indicator light goes out like it should but the the temperature will climb right up past the thermostat setting and keep on going until I turn the power off.

Anyone else experience this problem? Any ideas on how to fix it?

Bob-D659 · Oct 12, 2008

Sounds like an internal short or it's been mis-wired. Make sure the thermostat breaks the circuit to the heating element, not just the one to the indicator lamp.

paul ron · Oct 16, 2008

I'm not sure, but is there another sensor in the thing?

Shawn Dougherty · Oct 16, 2008

Alex Hawley said:
I recently bought a Seal 160M dry mount press on that auction site. The press is relatively new but the darn thing overheats. I've replace the thermostat with a new one but it hasn't fixed the problem. The amber heating indicator light goes out like it should but the the temperature will climb right up past the thermostat setting and keep on going until I turn the power off.

Anyone else experience this problem? Any ideas on how to fix it?

Alex, I'm have the SAME problem with a 210m I purchased. I even bought a new thermostat and still have the same issue. The problem is either that it's mis-wired or one of the wires is screwed up. I'm going to check out how my buddies press is hooked up. If it's that same as mine then I'll get my hands on a continuity tester and see which wire is causing the problem. The machine is so simple I don't think there is another possibility. I hope to do this within the next week. I'll let you know what happens. All the best. Shawn

DWThomas · Oct 16, 2008

(Speculation here, I don't own one...)

Do these presses perchance use a relay between the thermostat and the heating elements? If so, the relay might be sticking, contacts welded by arcing or the like.

(Well, there's no charge for this "advice.")

DaveT

Alex Hawley · Oct 16, 2008

Shawn Dougherty said:
Alex, I'm have the SAME problem with a 210m I purchased. I even bought a new thermostat and still have the same issue.

AHA! So its not just me and the press I have. That's really good to know Shawn and thanks for posting.

Dave, there's no relay in the circuit. I took the old thermostat apart today (very easy to do) and its a simple bimetalic strip device.

I think it may be the calibration of the thermostat itself. There's a calibration adjustment screw at the bottom of the knob stem. Had to borrow a screwdriver to get to it because none of mine were long and slender enough to reach the screw. Going to try adjusting the calibration tonight. Will post the results.

nc5p · Oct 16, 2008

Mine is the same way, so I put a big Variac transformer in front of it. I set it to 35% and it stays at the right temperature for my paper combination. One of these days I'll probably fix it properly.

Alex Hawley · Oct 16, 2008

nc5p, where does one get Variac transformers these days?

Alex Hawley · Oct 16, 2008

Tried calibrating the thermostat. No Joy. That means the heater has to wired in parallel with the thermostat instead of in series. Not easy to track down but necessary.

Shawn Dougherty · May 2, 2009

Alex Hawley said:
Tried calibrating the thermostat. No Joy. That means the heater has to wired in parallel with the thermostat instead of in series. Not easy to track down but necessary.

Alex, sorry for getting back so late. It turned out my problem was exactly what you just described, wired in parallel in stead of series. I have the wiring schematics, if you need them PM me. I ended up taking the press and schematics to a local electrician, who aside from melting my 100 pressure pad, was able to fix it. Mounted some prints last night and everything is working great. Good luck. Shawn

Alex Hawley · May 2, 2009

Thanks Shawn. PM on its way. I've been using the press by controlling it with the on/off switch. That's OK up to a point.

Streetwise · Nov 14, 2019

I know this thread is 11 years old now, but I have a Seal 210 (circa 1974) that started overheating, then one day started to smoke. I thought I would try it again with an old VariAC I had kicking around, but now all that functions is the power light...
After taking it apart, I discovered this melted sheath of wires. It looks like there's some sort of resister in it, plus it looks like the top was at one point, glued/welded to a stud that's bolted to the frame.

I only knew about a switch and a thermostat and sensor. What is it that melted? Can I bypass it somehow maybe with this?

RalphLambrecht · Nov 14, 2019

Alex Hawley said:
I recently bought a Seal 160M dry mount press on that auction site. The press is relatively new but the darn thing overheats. I've replace the thermostat with a new one but it hasn't fixed the problem. The amber heating indicator light goes out like it should but the the temperature will climb right up past the thermostat setting and keep on going until I turn the power off.

Anyone else experience this problem? Any ideas on how to fix it?

never experienced t5hat with mine.

Kino · Nov 14, 2019

That appears to be your thermistor, which regulates the temperature of your heating element!

No wonder it started to smoke!

If you can still read the nomenclature on it, you should be able to order a replacement here: https://www.mouser.com/Circuit-Prot...MI7ODM743r5QIVhZ-zCh2nMQQAEAAYASAAEgLNAvD_BwE

OR

Contact Omega Brandess for advice/parts:

http://www.omegabrandess.com/products/Parts

Streetwise · Nov 14, 2019

Thanks @Kino. It's burnt to a crisp. So I will contact Omega about Parts. Short of that, have you seen this video? I'm wondering if I could bypass it with this little box for $15.

Kino · Nov 14, 2019

Yep, it's more or less the same principal.

However, if you cut open that shrink wrapped bundle of wires, you should find a thermistor in a standard electronics "can" package with spade lug terminals. There should be nomenclature on the part to order an exact replacement from Mouser or Digikey, which might be even cheaper than that kit. All you would have to do is swap it out for the new one; making sure to keep the wiring the same and epoxy the new thermistor onto the aluminum stud with high temp epoxy.

Keeping the defective thermistor in the circuit might prove to be a fire hazard, as it is probably burnt and is almost certainly defective.

Kino · Nov 14, 2019

Oh and DO unplug the thing before attempting any repairs! I shouldn't have to say that but I'll throw that in for others who may read this and not have experience repairing electric equipment!

Streetwise · Nov 14, 2019

Kino said:
Oh and DO unplug the thing before attempting any repairs! I shouldn't have to say that but I'll throw that in for others who may read this and not have experience repairing electric equipment!

haha Too Late!!! Kidding....

Are you referring to the large 'dial' on the end of the bundle of wires as the thermistor? The heat tape is so stuck to it that I'm not sure I can get it off. There's also a smallish "can" type of package that you can see in the photo of me holding the bundle. It joins two wires together. But when I went to peel the heat tape off, the thing just flaked right apart in my fingers!

Kino · Nov 14, 2019

Dial?

I thought the two photos were of the same item. The thermistor should be at the end of the wires. I don't see any dial.

Kino · Nov 14, 2019

If there are other things rigged into your press, I withdraw all my suggestions and urge you to contact Omega. Someone might have rigged this unit prior to your obtaining it and I could be giving you bad advice!

Better safe than sorry...

Streetwise · Nov 15, 2019

I will do that. By "dial", I was trying to describe the shape of the object at the end of the wires. To me, it looks like there's an in-line resistor that is wired to the third, thinner white wire. I've attached an updated photo with stuff labeled, plus what's left of it.
As I think about it, I'll bet the epoxy came loose first, causing the press to over-heat the last few times I used it, and eventually the smokey melt-down when I left it on too long. So is the "thermistor" the same as a temperature sensor? Or is that all done by the thermostat dial in the front of the unit?

I will call Omega and see if they can offer any help.

Thank You!

Dave

Kino · Nov 15, 2019

I theorize that the resistor failed, allowing the thermistor to run full-power until the heat melted the epoxy and it separated from the heat sink.

It could be that the thermistor is still good, but will run full-power without a working resistor. Of course, something else could be defective up-stream, which would explain why the resistor is a charred mess.

In the end, it MIGHT be cheaper to implement your original idea of the outboard regulator IF you can find a safe way to hard-wire the heating element to bypass the thermistor and be regulated by the Elitech STC-1000 Temperature Controller.

It looks like the YouTube user who did the modification hasn't responded in years to questions and unfortunately, the two users above haven't been on Photrio/APUG for at least a year; one or both of them have the wiring diagram...

Kino · Nov 15, 2019

OK, found the diagram in the manual: https://www.kooltack.com/media/manuals/MASTERPIECE_210M_160M.pdf

Streetwise · Nov 15, 2019

Wow, thanks! I have an older 210 (non-M), but it does look like it would be the same. I've hooked it up to a variac at low voltage and chased the wires around with a voltage meter, so I'm gaining some familiarity with the layout. I'll know more after I talk to Omega.

Kino - I deeply appreciate your input on this! I would have absolutely no idea what a thermistor is. Never heard of that.

Dave

DWThomas · Nov 15, 2019

FWIW that schematic suggests to me it's not a "thermistor" but a mechanical thermostat. There are devices that have a slightly domed bimetallic disk in them that pops one way or the other at a preset temperature. We had a clothes dryer which was running hot and it turned out the normal dryer heat sensor had stuck permanently on, but a second thermostat that functioned as an overheat limit was setting the temperature. Normally they are mounted by some sort of stud or clamped down by a metal bracket. I'm thinking the fried unit upthread may have been stud-mounted and arced to the point it disintegrated itself. Anyway, if you can find a source for one of the desired temperature, it might be pretty inexpensive.

Seal Dry Mount Press Overheating

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