•1:10 PM
Last night our house's heat exchanger stopped working. I walked by the computerized thermostat and noticed that it was off. Dead. Kaput. "That's odd," I thought. So I walked around to the back of the house and checked the circuit breaker panels. None were tripped, so I cycled the compressor and heat exchanger's breakers and it still was off. So I inspected the compressor, and nothing was wrong. Then I inspected the heat exchanger and noticed something odd. The service disconnect was a little wonky. I pushed it a little, and I heard some buzzing inside.
Whoa. That's not a good noise.
So what is an A/C service disconnect? I didn't know until last night. It's basically a box that lets a service technician make sure that the power is off while working on the unit. It's kinda like unplugging a car battery while working on the engine. You don't want the starter to go off for whatever reason and take your arm off. So you disconnect the battery. This service disconnect does the same thing. Only in my case, it wouldn't and couldn't.
The thing is basically a switch. It has a block of plastic that has some metal conductors on it to bridge the gaps between two pairs of lugs. If the block is inserted fully, the electricity flows. If it is taken out, there is no way for the unit to get the power it needs. Ours happened to have one side connected and the other side broken. You see, for some reason, one of the pairs of lugs had a bad connection due to some sort of mechanical failure. It heated up and melted the plastic that was holding the lug in place, causing the heat exchanger to no longer receive power.
Before I continue the story, I should point out that, while I'm an electrical engineer, I'm not an electrician. The difference is significant, kinda like the difference between a nutritionist and a cook. The nutritionist knows what is good to eat. The cook knows how to make food taste good. An electrical engineer understands the rules about electrical properties and how to use electricity in cool ways. An electrician knows how to provide power for these purposes and deliver it in a safe way.
Being lacking in such understanding has not stopped me from dabbling in home or car wiring in the past. I remember as a teenager rigging up extension cords, a switch, and a light to provide light under my parent's crawl space. An electrician would not have smiled upon my work, but at least it was temporary. When I bought my house, I replaced the circuit breaker panel in the garage because it did not have enough circuits and was really old. So, armed with these kinds of experiences and a level head, I knew that I could fix this. It was, after all, only a switch, right?
So at this point, you are probably wondering how this story is going to turn into a debacle of incompetence. But it's not. I managed to cut away at the plastic so that I could remove the wires that were behind the fused plastic. For the night, I braided, taped, and wire-tied the wires whose connection was broken so that we could have heat. In the morning, I went to an electrical supply company and bought a new service disconnect. Then I installed it and everything is now working.
So what's the interesting part? Why write this story? It is a lesson in doing things yourself. By diagnosing the problem, I saved a visit from an HVAC repairman. The HVAC repairman may or may not have been qualified to work on an electrical service disconnect. By replacing the disconnect myself, I saved a visit from an electrician. It would probably have cost over $100 to get this $17 part replaced. It also helps to have a supportive wife. She wasn't too happy that I stayed up a little later to figure out a way to get heat despite having a broken disconnect. But she was supportive and proud of me.
-Brent
Whoa. That's not a good noise.
So what is an A/C service disconnect? I didn't know until last night. It's basically a box that lets a service technician make sure that the power is off while working on the unit. It's kinda like unplugging a car battery while working on the engine. You don't want the starter to go off for whatever reason and take your arm off. So you disconnect the battery. This service disconnect does the same thing. Only in my case, it wouldn't and couldn't.
The thing is basically a switch. It has a block of plastic that has some metal conductors on it to bridge the gaps between two pairs of lugs. If the block is inserted fully, the electricity flows. If it is taken out, there is no way for the unit to get the power it needs. Ours happened to have one side connected and the other side broken. You see, for some reason, one of the pairs of lugs had a bad connection due to some sort of mechanical failure. It heated up and melted the plastic that was holding the lug in place, causing the heat exchanger to no longer receive power.
Before I continue the story, I should point out that, while I'm an electrical engineer, I'm not an electrician. The difference is significant, kinda like the difference between a nutritionist and a cook. The nutritionist knows what is good to eat. The cook knows how to make food taste good. An electrical engineer understands the rules about electrical properties and how to use electricity in cool ways. An electrician knows how to provide power for these purposes and deliver it in a safe way.
Being lacking in such understanding has not stopped me from dabbling in home or car wiring in the past. I remember as a teenager rigging up extension cords, a switch, and a light to provide light under my parent's crawl space. An electrician would not have smiled upon my work, but at least it was temporary. When I bought my house, I replaced the circuit breaker panel in the garage because it did not have enough circuits and was really old. So, armed with these kinds of experiences and a level head, I knew that I could fix this. It was, after all, only a switch, right?
So at this point, you are probably wondering how this story is going to turn into a debacle of incompetence. But it's not. I managed to cut away at the plastic so that I could remove the wires that were behind the fused plastic. For the night, I braided, taped, and wire-tied the wires whose connection was broken so that we could have heat. In the morning, I went to an electrical supply company and bought a new service disconnect. Then I installed it and everything is now working.
So what's the interesting part? Why write this story? It is a lesson in doing things yourself. By diagnosing the problem, I saved a visit from an HVAC repairman. The HVAC repairman may or may not have been qualified to work on an electrical service disconnect. By replacing the disconnect myself, I saved a visit from an electrician. It would probably have cost over $100 to get this $17 part replaced. It also helps to have a supportive wife. She wasn't too happy that I stayed up a little later to figure out a way to get heat despite having a broken disconnect. But she was supportive and proud of me.
-Brent
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1 comments:
Brent, you are like your Dad - handy with projects around the house. It's great that Dad did so much of our repairs and upkeep on the cars, too. You are following in his footsteps. Don't put things off - that's easy to do. I think you have a lot going for you! Love, Mom