I left my unit plugged into the wall over the weekend but had the mode off so that it would not be heating my room. When I returned after the weekend I found that the heater has a yellow steady power button but does nothing else. I've tried to plug it into different outlets and even left it unplugged for the night but when I tried in the morning it still did not turn on. The yellow light turns on when plugged in immediately and stays on and does not change no matter what buttons I click. What should I do?

Heating & Cooling - Holmes Products - BH3955-U Bionaire Utility Heater