Wirsbo Thermostat


My friend has 5-6 Wisrbo 80465 thermostat broken.

I looked one.

It has all kind of electronics inside.

I started to draw a schemtic diagram.

It was like this.


I put +24VDC to pin 2
I put to pin 3 LED + 470R resitor to show when load is on and other end to pin 4.
I put ground to pin 4.

When I measured it , I found that double SMD-diode D3 was broken.

I replaced diode, which was marked A7W with similar BAS70 diode.

It started to work.


My friend give me a three broken thermostats more.

All have broken diode D3, BAS70.

Pekka OH3GDO

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