My boiler is working fine (35 years old) but will only take calls for heat from one of five thermostats which is the one in my basement. Originally I thought it was the control center before I realized this so I changed that out. Luckily the thermostat in the basement if we jack it up to 80 will help heat the rest of the house to limp along. I checked all wiring on thermostats and even changed one out to a brand new one which didn’t fix the issue. I came to the conclusion that it might be one of the two transformers that the thermostat wiring is connected to. One might be bad rendering most thermostats inoperable but the one that is working might be connected to the basement thermostat. If anyone can provide any input and let me know if I’m on the right track. I don’t have any equipment to test the current so I will just have to guess that’s the issue at this point. One transformer looks really old and the other was installed in 06. I included images for reference and if the birds nest of thermostat wiring they left me when I bought this house.
