Storage Heater Repair

[MichaelTT]

Hi all. I've reviewed the forum and tried to find information about a particular component that I require within a storage heater that I am attempting to repair, but am struggling to find anything and so I apologise in advance if this is a duplicate of an existing thread.

The storage heater does not have any coding etc on it, either on the front cover or anywhere else, yet I think it is a Sector STH330A. I have tested all 4 elements and they are fine. After testing the various components, the problem appears to be with the manual thermal cut-out, (the disk thermal cut-out on the right hand side of the uploaded image).

Can anyone tell me where I can find this part in order to replace it? I've seen one online for around £3.99 but want to be certain that I am purchasing the correct component. Alternatively, can this be reset?

Any help would be greatly appreciated,

Thanks - Mike.

 

[Taylortwocities]

Alternatively, can this be reset?

Yes (power off) press the black button on the top of the switch. You should be able to test continuity through the switch when it has been reset.

 

[MichaelTT]

Thank you for your response. I have tried pressing the black button but it doesn't move at all? Could it be jammed or simply require a replacement?

 

[Taylortwocities]

Interestingly, from your photo, there seems to be two thermal cut out switches in series. Do they have continuity, or is one/both open circuit?
The one on the left seems to be a bit damaged, and I would have expected there to be a button on that one too.

Note: I do not know the STH330A heater, and Google does not recognise it either. Are you sure about that STH330A number?

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[MichaelTT]

I'm not 100% sure on the name, sorry (I actually came across an image on an old thread on here with a picture of the same heater, and they had said it was that model number within the thread //www.diynot.com/diy/threads/sector-storage-heater-cutout-assembly-broken.420859/ ) The one on the left has continuity, the one on the right is open circuit. I've ordered a new thermal automatic cut-out (Disk type), similar to the one on the heater but without the button... It just seems odd that I cannot reset it.

 

[Iggifer]

I presume the little black 'button' doesn't unscrew to reveal a reset button?

 

[MichaelTT]

It doesn't twist off or anything.. However, I did just pull and push the black button repeatedly to see if it would loosen up... Reconnected the heater and it has powered up. When I tested voltage across the left component, I got 240v yet across the right hand component, I didn't get a reading. Any idea why this would be given that it is working? (I'm wondering whether the terminal is to covered up on the right hand side to make sufficient contact?) thank you for all your help! I've read loads of your responses on other forums and it's always really helpful advice!

 

[Iggifer]

Are you testing for voltage from one side of the cutout to the other? Or one side to something else?

 

[MichaelTT]

One side of the cut out to the other :/

 

[Iggifer]

That will always be 0V as you're testing Live to Live, there's no potential difference.

Test from the left side of the cutout to a known earth/neutral supply (the connector blocks that the incoming flex connects to is your best bet if you can reach it)

 

[EFLImpudence]

Reconnected the heater and it has powered up.

Do you mean working as in getting hot?

When I tested voltage across the left component, I got 240v yet across the right hand component, I didn't get a reading.

That suggests the left one is open so heater shouldn't be working.

Any idea why this would be given that it is working?

No. It doesn't make sense.

(I'm wondering whether the terminal is to covered up on the right hand side to make sufficient contact?)

You are there; we aren't.

 

[MichaelTT]

Thanks for your responses. Yes, working as in getting hot and I agree, it doesn't make sense.

Thank you for your response iggifer.. That does make sense to me however the component on the left hand side shows a voltage a 240v and is wired in the same way as the right hand component (series).

I will try what you have suggested iggifer and report back! Thanks for the help all it really is appreciated.

 

[MichaelTT]

Hi all - Just as an update. The heater had worked correctly for two nights but has failed again unfortunately. I tested the heater as per the above instructions and all was fine and I was getting the correct readings before I had reinstalled the heater. I have opted to replace the internal components with the repair kit as listed in the other thread //www.diynot.com/diy/threads/sector-storage-heater-cutout-assembly-broken.420859/ ) Thank you for all of your help. I'll post a picture when it has been repaired with the new components for future reference in case it ever comes up again!

 

[MichaelTT]

Hi All - Just as an update. I had fitted the new component and have attached an image for anybody else with this issue in the future. Many thanks all.

 

[MichaelTT]

here: