Thermostat teardown (one way) KSD301 & 90PM1

I wondered how those little things work. No electronics, no circuitry, it just works... What better way to find out then ripping it apart, right? Here is a look at the insides of two thermostats, the KSD301 and 90PM1.

[@visualchallenge2413]

Instructive video ! Just a note ... @ 9:24 the video seems to freeze but I think it was just a video editing problem. The video resume normally at 10:22. A A message "skip one minute" would solve this problem without reediting / uploading the video.

[@randomtronic]

Thanks! That's a new one... Must be a glitch in rendering as you said. It never happen before (I think...) Anyways, I have trimmed out that gap in YT editor, it is processing the edit now. It will not be pretty, but interruption will be just a second or two long. Besides, I was probably just waffling during that minute, so maybe its better that way ;) Thanks again!

[@sri20141]

Nice to see it, i was wondering what is inside. On seeing I realized it is the bimetallic plate

[@steefant]

These are called bimetallic strips (they are often rectangular). They were most famously used for turning signals in cars (you remember the sound for sure). Instead of measuring an external heat source they simply "measured" there own temperature changing from the current flowing through them. They have been increasingly replaced by electronic switches (the sound nowadays is artificial in many if not all cars) for that application but the principle is still often used and very reliable.

[@electroman1556]

omg! this I am asking for! thanks buddy. now i know

[@hipstarchild]

My Breville hot sandwich maker packed up on me today. Used about 3 times from new. I stripped it down and could only conclude that it was this thermostat that was causing the problem. After being on for a few minutes the power would trip out in the whole house. No bad Earths found. Thanks for sharing your video !

[@sirpuddles4473]

Hello! I had a portable steamer (like an clothing iron) that went out. Decided to take it apart and it turns out a transistor on the board blew out. Can't be bothered to repair it, but I did find one of these sensors inside. Thanks for the video! Interesting and educational!

[@techrsselectrician]

Nice video

[@blackopal3138]

Hey, man. Do you know if there is a difference with the KSD201? Is this just a newer model.? They are exactly the same visually, as well as temps can be found the same. But 201 are nearly impossible to find at the price of the 301, though Amazon does have a single listing for a 201 now.

[@jorgebitoon1081]

Thermo plate or bimetal

[@theveganvillainess]

Thanks I just bought a new heating component but the new one went out too, I think I got a bad thermal cut off switch as it's the only part with no continuity even after applying heat.

[@harolddasynth795]

Hi man,there is two types of this one,Normally open and normally close,what type is for radiator heaters?mine broke and i need to replace it,thanks

[@aaronmackay6123]

I have removed a ksd30 thermostat from my infrared heat. 16 amp 125 volt with a temp of 120. Is it supposed to rattle. My heater keeps turning off so I suspect the thermostat is not supposed to rattle.

[@randomtronic]

Yes, it is supposed to rattle. It's the little little dowel, it rattles. Your heater is overheating for some reason, that's why it keeps turning off. Look for reasons of overheating.

[@aaronmackay6123]

@@randomtronic I phoned and HVAC company and talked it through. Most likely reason he said was the length of wire before it gets to the heater. I have a hundred foot extension cord wired to my shed and a power bar in the shed. He said he thinks it's just not getting the voltage. So I'm putting it all back together and going to plug it in in the house directly to an outlet to see if it keeps kicking off.

[@StraleStrah]

Can I use ksd301 in place of ksd201

[@StraleStrah]

?

[@KayKay114]

I'm trying to figure out why my steamer is not producing heat. I found this on the inside. Thanks for the informational video!

[@Clark-Mills]

Cool, a bimetallic concave disc... as opposed to our usual leaf/finger... rather clever, thanks! :)

[@cortestv8509]

Hello, dear. At what temperature does the KSD301 disconnect? And what temperature does it turn on again after disconnecting? Thank you

[@garywiller9880]

They are all different. Depends on what you're working on. 40°celcius all the way to 150° c.

[@andrewjohn2929]

Hi...hopefully u can help me.. I was trying to change the thermostat for a garment steam cleaner (220-240v~50Hz - 1260 to 1500w)..but the specs on the thermostat has faded/melted away.. now im not sure what amp or resistance should i get? tq

[@randomtronic]

Hi, sorry, but I'm not sure what spec you should use. You have 2 parameters to look at: amperage and temperature. 1500w is about 6.5 Amps, so look for something above that, and the temp: well steam/boiling starts at 100 Celsius, I would think that the thermostat would be slightly above that, however, important thing to consider is that if the thermostat temp is too high, the pressure inside the vessel might raise above the vessel's rating and it might explode violently - so be careful. Only advice I can give: find schematic and figure out exact parameters, or don't repair - get a new steamer. Not worth the risk. Either way, good luck.

[@andrewjohn2929]

@@randomtronic tq Sir.. will probably get a new steamer

[@DarrenEnns1]

Please answer this question if you are able -- it will be appreciated! I have a defective KSD301 thermostat from a heater. The label says "16/125~ 120". I think this means that it is '16A' and '125V' and '120°C'. I think it should be OK to replace this with a '250V' model instead, right? It is much easier/cheaper to find '250V' versions instead of '125V' versions. Thanks!

[@randomtronic]

Yes, you are correct. Higher voltage rating means it can disconnect higher voltage. 250VAC thermostat will work just fine in lower voltage circuit. In fact it will "click" without any voltage, as it is a bi-metal switch. Change it, it will be fine. Good luck!

[@DarrenEnns1]

Thanks so much for taking the time to respond to my query! With that confidence, I was able to order very inexpensive units from Aliexpress :)

[@brianmarks6676]

Hi I have a question I have a thermostat out of a coffee maker part #ksd301-g 125v 16a 148 on it I can’t seem to find one with exact # Can you help me

[@randomtronic]

Hi, this 148 seems out of place. Have a look here:www.google.com/url?sa=t&source=web&rct=j&url=www.calcoelectric.com/images/pdfs_thermostats/calco_ksd301series.pdf&ved=2ahUKEwiwqf_XtLngAhW1URUIHTWkAlUQFjAAegQIAxAB&usg=AOvVaw3DgmtUdOhMguVvAEFdrla2

[@navedsyed9354]

no issue if it is 250 V or 125V you can use the coffee maker doesn't has much Ampere you can also use 10 A if 16 V is not available

[@MuhammadSyazwanMuskam]

good video