Hi all
I pulled this out of a non functioning dump load oil/radiant 700watt heater. I'm assuming it's a diode of some kind. It was between 2 of the safeties, one detecting heat, the other detecting tip over. Info on it as follows:
Cd E (But the E is the mathematical sign for something, epsilon?)
Tf 128deg C
D125 SNEU
Light blue band around the bottom.
Am I right that it's a diode?
Thanks
Ralph
Hi Ralph,
Would bet that this is a "Thermal Fuse", designed to protect against over-temperature conditions, if the thermostatic control fails in the ON condition.
FWIW, Vic
Thanks Vic. That's just what my EE friend said after I posted. Now to source one.
Ralph
Thermal fuse
https://www.digikey.com/products/en/circuit-protection/thermal-cutoffs-thermal-fuses/146
Replacement on order from a reasonably local company. 3 times cost of unit for shipping. It would fit in an envelope.
Son inlaw commented that if it failed once was that a safety reason it failed? Hmm. Bench test before putting into service, but it's good to know the fuse failed (if it was heat related).
Ralph
I think a lot of consumer items get thrown away when those thermal fuses open up. I have replaced some in various things that I salvaged here and there. You can usually find thermal fuses on ebay for not too much .
Larry
Does a thermal fuse blow when the temperature around it reaches the critical point (in this case 128deg C), or does the current passing through it cause the fuse to blow (from over current for too long?). Isn't that just like a regular fuse or breaker, but permanently wired in?
Never having heard of thermal fuses of this type leaves me in the dark.
Ralph
Quote from: ralph day on January 26, 2020, 08:04:41 AM
Does a thermal fuse blow when the temperature around it reaches the critical point (in this case 128deg C), or does the current passing through it cause the fuse to blow (from over current for too long?). Isn't that just like a regular fuse or breaker, but permanently wired in?
Never having heard of thermal fuses of this type leaves me in the dark.
Ralph
The heat opens them up .
This guy took one apart and explained how it worked.
https://youtu.be/bfTSa1skOHY
Larry
I like self resetting PTCs if the voltage and current rating are correct.
Never having heard of thermal fuses before last January I've had another visit with them. My daughter's first Instant Pot (pressure cooker) died. Again, it was the thermal fuse. $1.50 part, $3.00 shipping and we're back in business.
So anything that has heat, like a heater, Instant Pot, rice cooker etc will have one of these things. The selection is crazy. For 10 amp, 250volt there were dozens of various temperature ratings. The extra for last year's oil heater fix was 20deg C too low for the cooker, so not usable. My electronics stash now has 2 variants of thermal fuses, usable only in their purchased for use likely.
RAlph
Quote from: ralph day on April 09, 2021, 07:54:49 AM
Never having heard of thermal fuses before last January I've had another visit with them. My daughter's first Instant Pot (pressure cooker) died. Again, it was the thermal fuse. $1.50 part, $3.00 shipping and we're back in business.
So anything that has heat, like a heater, Instant Pot, rice cooker etc will have one of these things. The selection is crazy. For 10 amp, 250volt there were dozens of various temperature ratings. The extra for last year's oil heater fix was 20deg C too low for the cooker, so not usable. My electronics stash now has 2 variants of thermal fuses, usable only in their purchased for use likely.
RAlph
I bet UL or ETL or whoever the NRTL was made them put that part in there to make it safe.
The more parts there are, the more trouble you can have I suppose.