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Check the Resistance Readings of your Electric Floor Heating System

Digital multimeter

To ensure that your floor heating system will function properly, always test the resistance readings of your wires with a digital multimeter before, during and after installation.

Use the information contained in the installation manual for details. If at any point during one of your tests the resistance results do not match up, call the Warmup Technical Department. Watch our video specifically including information on testing

Warmup can provide your installer with the tools needed to perform a repair when possible.

If you purchased a Digital Multi-meter from Warmup, you will have 2 connectors.  Please make sure that the contacts that will be plugged into the multi-meter are properly exposed.

Connect the red clip into the outlet labeled “VΩmA” and the black connector into the “COM” outlet.  Turn the dial so that the indicator points to the 6 o’clock position, directly above the “200Ω” indicator.


IMPORTANT NOTE:  Perform the testing below before connecting the heating system to a power source or only after disconnecting if already installed.

1.  You will take your readings 3 times.

  • Once you first remove your heating system from the box
  • mid-way through the laying out of the floor heating system
  • right before you connect the floor heating system to the thermostat.

2.  Clip the alligator head of the black connector to the black wire of your heating system. The connect the alligator head of the red connector to the yellow (120V) / red (240V) wire.  This is your “core to core” reading.  Compare the ohm number that appears on the display to what the tag, box or installation manual state the reading should be for the model you purchased.  Note: +/- 5% of the norm is acceptable.

3.  Next clip the alligator head of the black connector to the black wire of the floor heating system and the alligator head of the red connector to the yellow/green or braided wire (ground).  You want to see the number “1” or the “infinity symbol – ∞.”.  Now you will leave the red wire connected to the yellow/green wire but this time clip the black connector to the yellow wire of the floor heating system.  Again, you want to see the number “1” or the infinity symbol.

If your results deviate in any way from the results indicated above call Warmup immediately for further instructions.

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