Honeywell THR860S timer problem

[rowanj]

I have this timer; I turned the power to the CH system off while troubleshooting a stuck 3-position valve (motor going). When I turned it back on the timer was completely dead - blank screen, no backlight, buttons not doing anything, both relays in off position.

I took the cover off and found the backup CR2032 battery inside was dead so I replaced that, but it's still the same. I've checked the power to the timer and it's fine.

Any ideas? Do I need to reset the timer in some way after replacing the battery? Or is it new timer time?

 

[Deleted member 267285]

Don’t they have x2 AA batteries inside? Have you checked them?

 

[rowanj]

Mine's mains powered - no batteries (apart from the backup coin cell).

 

[Deleted member 267285]

Mine's mains powered - no batteries (apart from the backup coin cell).

Apologies, when I googled that model, it came up with one with batteries. Have you checked for any loose wires? If not then I’m stumped, maybe the timer is goosed?

 

[rowanj]

Yeah, wiring is all fine, so I'm going to get a replacement. Inside all looks good too: no obvious blown components. Just weird that it gave up at exactly the same time as the battery and the valve. Thanks for looking!