A simple home repair riddle for yopur consideration. How many trips to the hardware store does it take to replace a thermocouple on your water heater? (For those who may not know, a thermocouple is a special wire that when heated creates a current. The current tells the controller the pilot light is burning and it is OK to send more gas to the main burner. If someone has a simpler, better explanation submit it in the comment section.)
Anyway to answer the riddle, it takes at least three trips. The first trip is to Home Depot to purchase the only replacement thermocouple they carry. After disassembling the burner section, you realize the initial thermocouple you purchased appears to be too long. Trip two is to Lowe's to purchase what appears to be the correct length part and also the only thermocouple they carry. Returning home you then realize that the two thermocouples you have purchased are right hand threaded where they screw into the controller. This is a problem since the original part is left hand threaded i.e. not righty tighty, lefty lucy. This requires a third trip to the hardware store to find out that, no they don't carry left-hand threaded thermocouples and the sales guy didn’t even know left handed threaded thermocouples exist. He did inform me that the length of your thermocouple really doesn’t matter, unless it’s too short (or screws in the wrong way).
By now it’s 8:00 Saturday night, so you put the old thermocouple back in. Previously the water heater would light, even if it went out after a day or two. But now that you’ve disassembled the thing and put it back together, it no longer even lights. So what do you do at this point? Call the 24 hour plumber, but no he doesn’t carry or have any left hand threaded thermocouples. However, he does happen to know from an experience earlier that day, that the particular brand you have is the only brand requiring a left-handed thermocouple. To get a replacement you have to call and have the factory ship a replacement part. Since it is the week-end it will be Tuesday before the part can be delivered to your home.
So after three trips to the home improvement store, two phone calls and few days of waiting, you too can have hot water restored in your home.