Seal 210 Drymount Press Wiring Help

[jlangley]

I'm really hoping someone can help me with this, I've searched for hours all over the internet and could not find a solution.
A few months ago, I got a seal 210 press so I could mount my photos. I got it off craigslist from an older lady who used it for making T-Shirts or something. When I got it, I plugged it in to test it and almost burned my house down. Even though the press was set to the lowest temperature, it kept heating non-stop. I noticed a strange smell, it was the rubber pad being completely melted by the press. I thought maybe the thermostat was bad so I actually was able to find a replacement for it (I also cleaned the melted pad off the platen and got a new pad heheh). The problem is... I installed the new thermostat and it STILL overheats

I have uploaded images of the problem along with descriptions of the photos here:
http://imgur.com/a/60eFr


Can anyone offer any insight on this? How is the thermostat supposed to work?

 

[waynecrider]

The best I could think is that you need a volt-ohm meter to check for continuity to see if there is a ground somewhere. Also make sure that the plug and associated wiring to the thermostat is correct for the hot wire being interrupted. Since you replaced the thermostat, make sure it is the correct one for the model and that the sensor is properly mounted.

 

[ic-racer]

Very odd.

 

[Mike Wilde]

There are multiple runs of heater wire ( coiled nichrome, I think) encased inside the top of the press inside an insulating high temperature woven cloth 'sock'. Some of the weave material may be asbestos; take care not to make more fibes airborne than is needed; they are not healthy to breathe in.

I have an old Seal press and the screws on the top of it allow the top half of the top to be removed to get at the heater sets, although I have not had to service them.

I suspect you may have a short in the heater wiring so there is less resistance seen by the source, hence more heat.

It may heat some local section of the press faster than the thermostat can sense to turn it off.

The insulation inside gets kind of brittle from being hot for many times over the years.

I suspect some insulation may have deteriorated and broken away as the unit was moved or inverted to clean it up, and a partial short thus may have developed.

I suspect you are going to have to take the top off, and go at it with an ohm meter with the power off as a first step, to see if one of the runs is of a substantially different voltage than the others, and troubleshoot from there.

Be aware that the resistance of nichrome changes radically as it warms up. Don't take the cold resistance as being an indication of how much heat the thing actually runs at.

 

[tkamiya]

I thought about this and thought about this..... Looked at a wiring diagram and thought about this some more.

The only conclusion I came to is that one of the previous owner(s) must have rewired it to act this way for whatever reason. It would take some really creative shorting inside to get it to act like that and I can't imagine this is a random accident.

 

[jlangley]

Thank you all for responding!

I thought the advice for using a meter was good so I tested the wiring. The meter readings were not really making much since, so I was able to determine that whoever had it before me did mess with the wiring for some reason. I re-arranged the wiring and finally got it to work! I tested it with a cooking thermometer and it now properly cycles on and off to maintain the set temperature, problem solved! Thanks again for the suggestions!