Electric Heat Troubleshooting, Service, and Math Class
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Bryan teaches the Kalos technicians about electric heat, often used as supplementary heat in heat pumps and furnaces. He also shares some stories from the field and teaches the techs a bit of math.
Heat strips are one form of electric heat. It would stand to reason that taking a bit of heat strip off wouldn’t hurt anything, but the electric heat would be less effective. However, when you factor Ohm’s law into the equation, you’d be taking off part of the heat strip and reducing the resistance, meaning that the amps will increase. Heat strips also burn out when they touch another piece of metal, like the casing around it, because the amp draw becomes much higher.
Electric heat has some benefits, including its consistent BTU output (3.41 BTUs per watt); regardless of the outdoor temperature, you can expect the same BTU output all the time. It is also reliable and usually easy to work on. However, it is inefficient.
Electric heat is the baseline of COP (coefficient of performance), and a pool heat pump that has a COP of 3 is three times more efficient than just the electric heat.
Electric heat has other issues, including odors or smoke when it first starts after a long time of inactivity. (It’s easy to burn off the heat strips on a PM, especially if you jumper W to R or use the thermostat to burn off the heat strips.) Electric heat also causes high bills when it runs too much and causes stress on the electrical service.
Electric heat elements also draw very high current, so you have to manage your wire sizing and electrical connections. You can also encounter mistakes with blower interlock; you don’t want to run the heat strips without the blower running.
Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.
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