If your wall heater is cycling on and off every 15 seconds, and you are controlling your heater with a digital thermostat, then likely you need to update one of the thermostat settings.
If you have a TH401, in the Set Up Menu, change the Heating Cycle from “Std” to “Fan”.
If you have a TH106, remove the thermostat cover, find Switch 3 and change the factory setting to the right, or the “On” position.
Review the owner’s guide for your specific thermostat for additional details.
If your thermostat is set up correctly or you do not have a digital control and your heater is cycling on and off less than every 5 minutes, you might have too much wattage for the size of the room. Contact our Technical Support team at 855-223-3788 for additional troubleshooting help.