How to test for amperage draw on the load side of a Smartstat thermostat.
To perform this test the thermostat 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. This wiring off the back side of the thermostat should be exposed (not in the wall) in order to perform this test. With the faceplate secured and the unit turned on, press the mode button (bottom left, under the left side shutter door) until a hand icon appears on the screen. This icon indicates that the unit is in manual mode. Open the door on the right side of the unit, and prss the arrow buttons up to 100 F ( 36 C), once this temperature is reached, press and hold the "sun" button (top right) until the "sun" icon appears on the screen next to the hand icon. 5 flame icons should also appear on the screen within 20-25 seconds after the sun appears on the screen. The flame icons indicate that the thermostat 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.