How to measure for amperage off of the load side of the Comfort Regulator.
To perform this test the regulator unit should be connected to house power (120 or 240 as appropriate for the heating system installed) as well as be connected to the floor heating system. The wiring off the back side of the regulator should be exposed (not in the wall) in order to perform this test. With the faceplate secured and the unit turned on, turn the dial to 10 (maximum power). An audible "click" may be heard within 20 - 25 seconds indicating that the unit is allowing current to pass to the load side (floor system) and an amperage draw can now be measured.
Please review the instructions for your particular multimeter on how to read for amperage. Some meters will require that they be in line with the circuit to gauge a reading, while some are equipped with a large clamp to encircle the load wires. Either variety will work for this test, and as always exercise extreme caution when performing these tests. Live voltage is involved.