The Best Way to Check Whether or Not a Heater is Operating Correctly on the Line
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We received a question from a customer the other day regarding how to check whether or not a heater is operating correctly on the line. This is a great question! But, how do you actually know if a heater is operating correctly or not? Our answer is this: The best and safest way to check a single phase heater that is still on a machine is to…
- Turn off power to the heater and disconnect the lead wires.
- Find the number engraved on the heater specifying the watts and volts. (See photo)
- Measure the resistance between the two lead wires or two post terminals, depending on the heater.
- The resistance should be close to the voltage squared divided by the wattage (for you mathematicians out there, here is a formula: R = V^2 / W)
For example: You have a 500 W – 240 V heater.
R = 240^2 / 500
R= 115.2 omhs
Standard tolerances allow for resistance to measure between -10% and +5% of this total when the heater is at room temperature. If the heater is still at operating temperature expect resistances in the range of -5% to +10% of the calculated total.
Have a question for us about your heater? Visit our contact us page or email our engineering department at engineeering@thermalcorp.com!
Written by Kyle Otte
Edited by Shelby Reece
Date Published: 07.19.2018
Last Updated: 09.06.2019
