Check the matched low-voltage system and allow the documented warm-up time.
For a FeelsWarm stick-on countertop heater, check that the supplied power supply is connected and any optional Thermal Control Unit is on and set appropriately. The heater warms gradually: the manufacturer says the countertop may take up to 90 minutes to reach its stable warmth, and a control adjustment can take about 30 minutes to become noticeable.
Inspect the visible cord, connectors and mat without pulling on the cable or peeling the heater. If the mat is damaged or peeling, disconnect the power supply and contact FeelsWarm for service.
The mat operates on low-voltage DC, not household line voltage. The manual covers 9–24 V DC systems and explicitly prohibits substituting a different transformer. Use the voltage and ratings supplied with the specific heater; do not apply 120 V directly to the mat.
If basic checks do not resolve the problem, a qualified technician should test the outlet, matched power supply, optional control and heater separately using their ratings. Do not diagnose all mats on a fixed 200-ohm meter range or equate zero resistance with an open circuit. Contact FeelsWarm support at (952) 898-9505 with the serial number and system details before replacing components.
Source: FeelsWarm Stick-On Heater installation instructions (page 3).