Danfoss p5000si inbuilt obsolescence?. Hard wired button battery at low 1.5v - can't programme!

[jkam]

Can you help please before Xmas & my cutting out the battery & struggle to attach 3v source. (I am trained in electronics)
Danfoss p5000si inbuilt obsolescence?. Hard wired button battery at low 1.5v - can't programme!
No reference to this in any manuals nor help on the internet.
I called & emailed Danfoss but the public are shunned.
Help, we are without a boiler.
Thank You & Happy Xmas

 

[JohnD]

I don't know that one in particular, but if you are handy with a soldering iron you can often fit a new replacement battery.

They are often green, and I think made by Varta. You might have room for a higher capacity replacement.

You can use a magnifying glass or a phone camera set on zoom to read the inscription on the old one.

It was @bernardgreen who helped me when I had a similar problem.

You can also get battery and cell holders with wire pigtails which are easier to fit than batteries with tags, and can be re-used next time.

 

[JohnD]

P.S.

Correction.

It is probably not the battery,

You mention you have an SI controller

These are deliberately designed to stop working properly at intervals and prevent the user resetting or programming it. "SI" means "service interval." So that the householder has to pay for a service. I understand they are marketed to owners of rental properties. IMO such devices are ideally installed in a skip.

 

[jj4091]

Perhaps you can reset it after replacing the battery https://www.swaleheating.com/about-...o-reset-your-danfoss-programmable-thermostat/

 

[DP]

Function of that battery is to maintain the programmer when the AA batteries are removed for replacement.
Fail to see the reason why that battery needs replacing. Not had the urge or temptation to do so in 30 years I have been using that programmer

 

[polesapart]

As above, simple reset is probably all that is required.

https://cdn.expertelectrical.co.uk/media/catalog/product/t/p/tp5000si-instructions.pdf
pp24,28




If the unit has failed (less likely but possible) put a link wire between terminals 2 and 3 on the backplate as a temporary override.

T2 often 240V, isolate and test first.

All the electronics do is switch continuity between T2 and T4 "off" and T2 to T3 i.e. "call for heat" or "on"