Problem with Danfoss FP715Si Programmer

[LittleTyke]

Yes, it's the main volt dropper. I don't know about dimming the LEDs. In the case of the one I have here the LCD went before the LEDs.

Having just read a bunch of stuff about capacitive dropper power supplies, is Danfoss going the X1 route to avoid the cost of a proper switching power supply to drop 230V to 5V? In one video the guy says near the end "That is why capacitive dropper power supplies are super dangerous and should always be positioned inside a closed housing."

 

[Moley]

I would say 'super dangerous' is a bit of an exaggeration. They don't isolate the output from the mains input so yes, they should be enclosed. Apart from that they are no more dangerous than any other. It's not just Danfoss that use them. Dropper caps are used quite a bit in enclosed equipment. I would imagine you will have quite a few scattered around the house especially if you have LED light bulbs, remote sockets etc. If a switch mode power supply was used it would increase the size by quite a lot too.

 

[Moley]

I've just checked the cap I took out. It should be 474nF. It's reading 327nf with an ESR = 3.4ohm

 

[LittleTyke]

I would say 'super dangerous' is a bit of an exaggeration. They don't isolate the output from the mains input so yes, they should be enclosed. Apart from that they are no more dangerous than any other. It's not just Danfoss that use them. Dropper caps are used quite a bit in enclosed equipment. I would imagine you will have quite a few scattered around the house especially if you have LED light bulbs, remote sockets etc. If a switch mode power supply was used it would increase the size by quite a lot too.

"If a switch mode power supply was used it would increase the size by quite a lot too."

Yes, I did wonder about that.

 

[The Winetaster]

Excellent review and guidance, just read the whole thread as my programmer has just set the same issues:
1) Fixed screen with set time
2) Unresponsive selection buttons.
3) Red LED’s for DHW and CH permanently on

Will now order a replacement as this CP715 is 25 years old and I think it’s had its day!!

Thanks for the detail.

Especially like the "Never take a sleeping tablet and a laxative at the same time!!" comment from Moley