I recognize so stupid. My partner and I bought our current condo a few months ago. Since then, all of us have had a lot of studying to do as a lot of small things seemed to beginning going wrong. There were plumbing leaks, a roof leak, and then the cooling system stopped entirely working. Both of us just decided to difficult out the cooling system issue because all of us simply couldn’t afford another service on top of all of the other expense, but when another month past, and the temperature started climbing, all of us finally broke down and call out and cooling system serviceman. But first, all of us called around and found an Heating, Ventilation, and A/C supplier that takes payments because all of us were expecting the worst; Reading online, it looked enjoy all of us might have a service that cost a few thousand dollars and would require completely replacing, or almost completely replacing our cooling system. So when the serviceman arrived, my partner and I both held our breaths as he looked our component over. He then went out to his truck, came back with a battery, pulled the control unit off of the wall and upgraded the battery that had been in there. Within hour, our cooling system started entirely working again. I had to laugh, all of us could have upgraded the battery a month ago and had our cooling system entirely working. The serviceman explained this sort of thing happens all of the time. I assumed that the control unit was wired into the wall. I had no program it had a battery. Every one of us just had to pay a small service fee but it would have cost us only a few dollars to have upgrade the battery ourselves.