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My baseboard heater stopped working. It has been working at this house since it was installed over 40 years ago. The breaker didn't trip. Then I tested the wall thermostat which is working fine. I get continuity once I hear the thermostat click.

Next I opened the baseboard heater which is rated at 240/208 VAC 2000/1500 Watts. I measured the resistance of the heating element at 35 ohms. It should be about 26 ohms so not sure if this is an issue.

Assuming it isn't I was able to locate the thermal cutoff link, but it has a wire that goes along the inside top of the heater. I measured the resistance across the link and it registers as an open circuit. I wanted to try to replace this however it seems it cannot be removed as the wire seems to be a part of the piece and can't be separated. See pics

Am I able to replace just this piece without the wire? Not sure how to proceed. Any help would be greatly appreciated.

Thanks

Here are the pictures. I was having trouble attaching them. Sorry

!(https://drive.google.com/file/d/1FJPYEXsY4g69Vo6O0ApxhjXdsL59xrvG/view?usp=sharing)

!(https://drive.google.com/file/d/1yjj7eVAmq9dT_EkjAKMh1omezMsqxNpK/view?usp=sharing)

Pic of other end of the wire coming from the thermal cutoff link !(https://drive.google.com/file/d/1M3RCvXa26qQ-Ie2cGEdiQj9FzKsqsJwO/view?usp=sharing)

Picture of thermal cutoff link and thermocouple !(https://drive.google.com/file/d/1_8DVsyvOD0JfRNd-nc9kMLQXUAsKL8f1/view?usp=sharing)

The issue was in fact the thermal cutoff switch. When i got i tested the conductivity before installing it just to be sure. I placed it in the heater and now i am getting heat.

Guest
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2 Answers2

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Usually a thermal cutoff is wired in series with the heating element and is intended to OPEN the circuit if the thermal threshold is reached. Some models self-reset but most are one-time use. Once they trip they must be replace.

Manufacturers often solder or, more commonly, crimp these in place. A common type looks like this:

Thermal Cutoff

or this:

Larger thermal cutoff

In either case they are replaceable but you must get a replacement of the correct capacity and temperature. It's also possible that it's wired such that it doesn't open the heater circuit itself but instead opens the thermostat circuit so the heater won't turn on. Water heaters are commonly wired this way.

There should be markings on the device that show its part number and/or it's temperature value. The case type often indicates the capacity/amperage. You might also check with the manufacturer to see if they sell a replacement part for your specific heater.

jwh20
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  • Hi. Thanks for your detailed answer. I was able to finally add the photos. Sorry I am new to this site. I have found the cutoff but it has a wire that seems to be part of the piece. It's not soldered it seems. Can this piece be replaced. Not sure how to remove the wire. – Guest Jun 27 '22 at 17:29
  • @Guest That bare wire is usually clamped close to the heating element. Take a picture of the other end of it. – JACK Jun 27 '22 at 18:19
  • I just took a picture of the other end and it doesn't go anywhere. It seems it was cut. Is this wire for the thermostat in case I am not using a wall mounted thermostat? In my case I have a Honeywell T498A1786 thermostat but it seems to be working as it shorted when I heard the click. – Guest Jun 27 '22 at 18:30
  • I have attached pic to the main post – Guest Jun 27 '22 at 18:30
  • @Guest That's a thermocouple. It's what senses the temperature and triggers the switch to open at high temperature. Just un clip the wire and bring the unit to an appliance repair store or search the web. It'd not the same as a thermostat. It's a high temp limit. – JACK Jun 27 '22 at 19:16
  • Thanks again. I removed the cutoff and thermocouple shown in my last pic. I will try and replace it and let you know if this solved this issue. In any case you have been great thanks. – Guest Jun 27 '22 at 20:09
  • I got the thermal cutoff switch replacement and now the heater is working fine. Thank you for all your help – Guest Jul 06 '22 at 22:43
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That’s only a 8.3 amp heater.

the switch is just a standard safety that it heats up and opens.

thermocouples produce a voltage that goes back to a controller or gas valve.

What you need is the numbers off the switch to find the temp at cutout. The cost of baseboard heaters depends on the length as the short ones are cheaper for the same wattage. The length of metal is a tube that heats up and actuates the switch.

Why can’t you use a standard snap switch with the correct temp range ( you can but then high temp fixture wire would be needed to connect to it)

So the best option will be to get a new sensor and cut the old one out. But I would verify that is the problem (the switch is open) the 10 ohms difference is no big deal.

Ed Beal
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  • I ordered the thermal cutoff link and thermocouple. It should arrive Thursday or Friday. The 35 ohm measurement was for the heating element. The thermal cutoff link measured infinity so it seems defective. – Guest Jun 28 '22 at 20:10
  • Yes the resistance of the heating element you measured at 35 but said it was supposed to be 26, this is fine. – Ed Beal Jun 29 '22 at 04:15
  • What did it cost for the parts? I have a baseboard heater that failed but I just bought a replacement instead, still have the old one waiting for me to look at it. – Fresh Codemonger Jul 07 '22 at 00:06