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-   -   Bimetallic Heater Cut Out (https://www.vintage-radio.net/forum/showthread.php?t=169403)

Glowing Bits! 26th Jul 2020 6:49 pm

Bimetallic Heater Cut Out
 
2 Attachment(s)
I have a small 1KW heater that needs a new cut out device but can't find one that looks the same or even figure out what temp it trips at, there's two wired together and placed just before the elements, it's in the blast path of the fan.
I have included two pics of it, hopefully someone can point me to what I need, one does work but the other has been attacked by the nearby element, it's clearly had an electrical flash-over take place.
For your info, it was made sometime in the 70's, the original devices are Otter brand.
Any help or pointers greatly appreciated, thanks.
Mods, please move to a relevant section if need be.

Julesomega 26th Jul 2020 8:17 pm

Re: Bimetallic Heater Cut Out
 
1 Attachment(s)
You reminded me that I was supposed to fit a new fan heater in the shower room: nothing wrong with the one we've got but when I fitted one for a tenant SWMBO was vexed that I hadn't got her one. The replacement is a Glen Downflow Fan Heater which is superior in that it is has a simple on-off switch whereas the old one has off-500W-1kW-2kW-off. The Glen comes on at 2kW and if the room warms up enough it switches to 1kW. The change-over temperature is pre-set if you take the cover off. Seemed good value.

Anyway, said tenant was forever having trouble with her storage heaters. It's difficult to understand thermostats if you come from a hot country, and especially on a storage heater. Once I had shown her how to turn up the thermostat she turned it to max and the plastic bits started melting. One t'stat was indeed faulty so I found one on eBay. The seller sent me the non-adjustable equivalent but didn't want it back so it is now spare. I took a good one out of one of the heaters when I changed it for a non-storage type which suits her better. I will soon have several more when I scrap all the storers.

Each type is in two stages, probably for the same reason as yours, to provide an over-temp cutout which requires you to open up the heater to reset. You can see both stats in the photo. One is settable for normal (British) room temperatures, the cut-out is about 120°

AC/HL 27th Jul 2020 12:19 am

Re: Bimetallic Heater Cut Out
 
Otter are still in business: http://www.ottercontrols.co.uk/cutouts.html#gsc.tab=0

Glowing Bits! 27th Jul 2020 12:29 am

Re: Bimetallic Heater Cut Out
 
I had a look at their site in previous times but can't figure out who stocks them.
The main issue at the moment is establishing what temperature is needed, a test may have to be performed by shorting the stat wires, temp probe on the metal work, run it for a while then draw a conclusion.
It could be operated without any cut out devices but it's to be used in a motorhome, I don't fancy the motor stopping and a fire starting.

AC/HL 27th Jul 2020 12:44 am

Re: Bimetallic Heater Cut Out
 
Some here 54degrees: https://www.ebay.co.uk/itm/OTTER-V1-...oAAOxyDEVSamNO

Glowing Bits! 27th Jul 2020 1:23 am

Re: Bimetallic Heater Cut Out
 
Already found them but thought the temp may need to be higher, I may be wrong though.
A test will be performed in due course to establish how hot the metal by the stats get, the Ebay ones may be of use if the temp stays low enough.

Glowing Bits! 27th Jul 2020 1:53 am

Re: Bimetallic Heater Cut Out
 
Just done a quick test by shorting the stat connectors, poke a probe through a hole where the stats are and it's pretty much conclusive, the temp when running is not exceeding 50 centigrade, abruptly turning it off at the mains gives a rise above 90 centigrade, something rated in the 100 region may be suitable.


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