Heated Floor Not Working? Electric Floor Heat Fixes

Is it calling for heat?

The heating symbol. Warmup says to look for the heating indicator, an icon on the screen or a small light, depending on the model. If it is off, the thermostat is not calling for heat, so the settings are the place to look.

Warmup’s list. A “heating off” message that overrides the schedules, a schedule or date and time set wrong, and manual mode with no target temperature. The target has to be above the current floor temperature.

Schluter’s RS1 list. The word “Limit” means the maximum floor or room temperature has been reached, and it heats again once the temperature drops below it. A thermostat locked from the app will not change its set point, and Away mode can be switched on by another user of the account.

Nest. Nuheat says that when a linked Nest thermostat goes to Away, its Signature thermostat stops heating the floor until the Nest goes back to Home. If the screen shows the floor warmer than it feels, see the sensor in check 5.

A red light or a GFCI error

A test, not a fault. Nuheat says that pressing the GFCI Test button shows a GFCI error and the red light, which is normal, and the Reset button clears it.

Nuheat’s lights. A solid red light or a slow blink: press the on and off button to reset the GFCI. A fast blink means a ground fault in the heating system, so call your electrician or installer. A red light at the top or right side that will not go off also means a ground fault.

Nuheat’s steps for owners. Press the reset button once. If the red light stays, turn the floor’s breaker off for 10 seconds and back on. If the error comes back as soon as the power is back, call an electrician.

Schluter’s RS1. A GFCI FAULT is reset with the RESET button on the side. If it trips again, Schluter says the cable may be short circuited or the thermostat defective. Its E17 code means the GFCI’s self-test failed: press reset, and if it shows again, reset the breaker.

A blank screen

Power first. Schluter says a blank screen can be no power, so check the breaker for the thermostat and floor is still on. Nuheat says to press the GFCI test button: if the red light comes on, there is power to the thermostat. If it does not, Nuheat says confirm the breaker is on, then call your electrician to check the wiring.

Nuheat’s restart. Turn the breaker off for 10 seconds and back on, then hold the on and off button for 4 seconds, release, and wait 4 seconds for the screen.

When it is the thermostat. Nuheat says that if a thermostat that worked before stays blank with power to it, it needs replacing. On a brand new install, Nuheat says a blank screen most likely means the line and load wires were switched, a job for the electrician. Schluter adds a cover not attached properly to its case.

A code or a sensor message

Schluter’s RS1 codes. CHECK FLOOR SENSOR means it is set to floor control with no sensor connected. E1 and E2 are its internal room sensor, and Schluter’s fix is the breaker off for about 30 seconds and back on. E19 means it is too hot inside and OL that the load is too high: Schluter says the cables on one thermostat must not exceed 15 amps. HH and LL mean the room is above or below the thermostat’s reading range. Schluter says keep it between 32 and 122 degrees, and if it was above 122, let it cool for at least an hour before the breaker reset.

Nuheat’s sensor message. “Thermostat is not functioning properly” with a floor sensor status of Fail means the sensor may be damaged, missing or not connected. Nuheat’s next step takes the faceplate off to check for two small black sensor wires in terminals C and D. Its electrician steps turn the floor’s breaker off before the faceplate comes off, so do the same, or leave it to your installer. If the message comes back, Nuheat says contact your installer to replace the sensor.

Until it is fixed. Nuheat says the thermostat can be switched to control by the room temperature for the time being, and switched back to floor once the sensor is replaced.

The heat is on, but the floor stays cold

Give it time. Warmup says cables deeper in the floor take longer to heat the surface. A bare concrete slab with no insulation under the heating soaks up heat first, so the floor takes longer to warm. Google says radiant systems generally take much longer to heat up than forced air.

Warmup’s fixes for a slab. Raise the setback temperature, the lowest temperature the floor keeps all the time, and start the schedules earlier. Nuheat suggests starting a schedule at least 30 to 60 minutes before you want the floor warm, if Early Start is off.

A sensor that reads high. If the screen shows the floor warmer than it feels, Warmup says the thermostat may not heat because it thinks the floor is already warm. The sensor belongs halfway between two cable runs, and one too close to a cable, or with its wire in the same conduit as the cable’s cold lead, can read high. Warmup’s fix is to switch the thermostat to control by the room temperature. Schluter adds the sensor’s resistance setting, 10K or 12K, and its offset.

A new thermostat. Nuheat says its Signature and Home thermostats take 3 to 5 days of uninterrupted heating to learn the floor, and can overshoot or undershoot until then. Schluter says the same of its RS1.

Then the electrician. Warmup says that once the settings and the sensor reading are ruled out, and the heating symbol is on but the floor stays cold, call an electrician for the electrical tests.

The cable itself

The resistance test. Warmup says the electrician checks the cable’s resistance with a digital multimeter: within 5 percent of the cable’s own figure is normal. Nuheat tests at the factory cold lead: more than 10 percent above or 5 percent below, or an open line, means the element has been affected and needs a technician.

Insulation, and the readings from the install. Nuheat’s insulation test should show an open line, and any other reading means the element is affected. Warmup says compare with the readings taken at installation: a big change can mean the cable was damaged after it went in.

Floor or thermostat? With the cable wires disconnected, Nuheat says a thermostat that still trips its GFCI needs its GFCI replaced. One that trips only with the cable connected points to the floor, and a repair technician.

Repairs. Warmup says your electrician repairs the cable once the break has been located, with repair kits free from Warmup. Nuheat also checks the supply breaker is a standard one, not a GFCI breaker, on a circuit only for the floor.