Hi folks

I have what some burn wire connection on what I think may be the safety thermostat on my Profitec Pro 800.

Can anyone confirm this is the case?

If I order a thermostat replacement, will it come with the connecting wires also? Can I just buy the wire connectors?


This is a photo of the whole left side of the machine from the top.



This is a closer photo of the same.

Defective components do not usually cause burnt wiring of this type. Chances are, your thermostat is still good; you'll have to remove the connector to see. Loose connections and corrosion cause problems like this. Probably the connector was not tight in the first place. Such failures are a kind of China syndrome; that is, as they fail, they cause additional failures in a vicious circle.

The first thing to do is to remove the connector and see if the thermostat is burnt. If it's not, then get a small brass wire brush and clean up the terminals. Buy a good quality replacement connector (IE, not a kit from Walmart) and put it on the wire with a ratchet crimper (again, not from a bargain store). This can be tricky, as you'll need to cut the wire back until you see bright copper (the heat will have annealed the wire near the joint). Cutting the wire back may render it too short, in which case the entire wire should be replaced. If this is not possible, then a soldered Western Union splice will be needed, covered with heat-shrink tubing, not electrical tape.

Looking at the angle at which that terminal is rivetted to the thermostat, I'm going to guess that the thermostat is bad too, either the rivet is bad and the terminal is flopping loosely on it making bad contact, thus heat, or the thermostat has overheated enough to burn the plastic and warp out of shape. I would replace the thermostat as well as the last couple inches of the wire and the push-connector and insulator.

The thermostatic resettable sensor has been burnt too, compare its casing to that of the sensor just behind it. Replace both the sensor and the burnt wire and connector!

Thanks for the input folks. Are these little 145° thermostats specialty items or can I pick them up in my electrical stores?

Here are a few more photos now that I've had time to open the case.

Are there two thermostats for safety/fail safe?

Out of curiosity, can I simply by pass the thermostat by shorting that circuit on? (Connect the wires together)?

At least until I can get a replacement thermostat. Being in Japan, it'll likely take me a month or two to get a replacement. I'd rather not be without my machine for that long, but I also don't want to permanently damage the machine nor start a fire.

Yes, both thermostat are for safety, you can temporarily bypass the burnt one.
Disconnect the blue wire/connector from the heating element.
From the burnt thermostat move the non damaged blue wire to the heating element.

Giampiero wrote:Yes, both thermostat are for safety, you can temporarily bypass the burnt one.

Can & Should are 2-different things. I would NOT advise bypassing or modifying anything that are in a circuit for safety reasons - especially without seeing and having a full understanding of the circuit schematic.

You can also bypass a Smoke Detector by removing the battery - I won't advise that either!

I agree with you, especially if my suggestion got misinterpreted by the OP.
To clarify your doubt, both thermostats are respectively on the phase and neutral line before the heating element, a TEMPORARILY bypass of one of them should not cause safety issue, unless the remaining thermostat fail too, mostly of the manufacturers installing a single safety thermostat...and seems to me no one customers felt in danger for that.

I read I should be using around a 14-16 gauge wire for this, but that seems overkill for a thermostat, right?