Horstmann Economy 7 Immersion Timer battery problem?

2 Jun 2021
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United Kingdom

Summary: I am looking to buy a replacement battery. Does anyone know where or how to find one? I believe this is the problem.

I changed the tank to a thermal store.
I left the Horstmann switched off at the mains ie no power to charge the battery, for several years. Apparently they won't work if the battery doesn't have correct voltage ie has been allowed to go flat, which mine has probably.

I eventually got it connected up to the new thermal store. There is one power cable into unit, and one cable to tank.

Originally, when connected to old tank, the timer unit "ticked" as it went round. It no longer makes a noise or goes round!

The boost light and timer lights come on - see pictures, but water doesn't appear to get heated.

I suspect the battery. It doesn't look hard for an electrician to re-solder a new one in.

Other possibilities? heating element wasn't wired into new tank correctly, but surely timer would go round and "tick"?

I am trying to avoid the expense & waste of buying a new Horstmann (and would love any suggestions that don't involve buying a new Horstmann!). Having got very inspired by a fantastic post on mending a Miele washing machine (only 2 components for less than £5 needed!!), I have renewed vigour to mend things.

Boost light comes on, but dial doesn't move.

Night timer light comes on when I manually turn timer round to 3.30 am. Timer dial doesn't "tick" or turn automatically.

thanks in advance, Sarah
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When I looked many years ago I couldn’t find a replacement battery. So let me know if you do find one
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I found several rechargeable stand-by batteries for various timers. I think it was @bernardgreen who showed me what to look for. IIRC the ones I got were rechargeable Lithium, and I tended to get slightly higher capacity than the original (there is not usually much room for a bigger one, but shapes vary.) Some come with wired pigtails that can be reasonably easy to solder on if you clip through the old ones. In one case (the casing of the device was very hard to open) I ran the connecting wires outside the casing to make it easier to change next time. I also have an MK DIN-rail timer where the standby battery is not rechargeable, but has a life of quite a few years.

might have been a Swiss maker? With green coverings?

when people downgrade to Combi boilers, they often put their old Horstmann on ebay, so you can pick one up at low price.

edit again
it was this one

Varta Mempac
I think I ordered from Rapid.
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upload_2021-6-2_18-48-10.png Thank you John, and CBW, It is very exciting to have replies already.

I followed the thread you posted John but my battery is not like that.

Could you tell me what IIRC is? And is Varta Mempac a battery brand?

Above is picture of mine and the writing on it says: Rechargeable; A; NIMH
and same number as CBW's reply! 320BVH And as you can see, it has pig-tails. I think even I can solder onto that!

CBW- thank you! will try that.

I measured the voltage - it may as well been a lump of metal, I have never seen a battery at 0.1 V!
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Apologies, I only searched, didn’t check availability.

Strange, I didn't find anything at all, available or not. Thanks for link, will check it out.

AndyPRK, let me know if you find one too!

It's amazing when things are thrown away for want of something so small!
I did find this though, you could always contact them and see if they’ll make you one, or if they stock it?https://cellpacksolutions.co.uk/

Also maybe contact GP batteries or Horstmann?.

I checked GP Batteries, and nothing again. I have emailed Cell Pack Solutions.

I really wonder what I am doing wrong with my searches!

On cellpacksolutions there were these. They have numbers after (and are different shape, although I don't mind that) - am I looking for one without numbers after?

Some knowledgeable people who may know: @stem and @ianmcd

Great! thank you
Is it possible for me to contact them, or will the @ notify them?

I've now written to 3 or 4 companies. I have posted a reply that is waiting moderation, with some batteries which have numbers after
  • Thanks
Reactions: CBW
Sorry I dont know, I would try RS Components, google 320bvh nimh there are loads, see if you see one that matches yours, wouldnt have thought it would be the battery to be honest, most likely the motor
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