Hi, after 3 years of operating one of my Noma HTM611A Thermostats stops working without no reason. It shows nothing on the panel but an empty arrow and 9:00 as a clock which is not ticking.
I checked all the brakers, the connections of the thermostat itself and the radiator. All seems normal.
And no one touched it for sure, because it was working in the morning and when we came home THIS room was cold and the thermostat was dead.
What could be the reason? Please! That's the babies room and it's time to go to bed for them.

Does this thermostat serve only the baby's room? Are all other thermostats working fine? And are the other thermostats the same as the one in that room? If they are the same, kill the power the to furnace, and swap one of the other stats out for that stat. Turn power back on and see if it works. If it does, you need a new stat. What type system do you have? Hot water, forced air, electric etc?

Thank you SO VERY MUCH FOR the quick answer.
Yes, it serves only for that room. All the stats are the same and they are working fine. I'm afraid to start playing with changing stats because it's minus 10 Celsius outside and snowing nuts. My son was just diagnosed with pneumonia today and he's in the Emergency room with mama and I'm fighting the heating in their room because that's the only place in the house my kids could sleep. I must fix it by night and there are electricians available.
All the heating in the house is electrical baseboards.
The connections in the box seem to be fine. The connections inside of the thermostat I don't see and I'm afraid to open the plastic box because it seems as monolith. What do you think?

Okay. Sorry to hear about your son. Since it is electric baseboard, I really would suggest getting an electrician in there asap. You say they are available, so use them now if ever. They really should be able to get you up and running in short order. Please let me know how this work out. Take care, and good luck friend.