Replace the sensor. I had one where I had to repeatedly replace the sensor. It is a design flaw. The sensor is a tiny plastic part, but mine had cost about $20. It is very sensitive to dust, dirt, water, etc. and it will blow and tank won't work. You can google your model and find where the sensor is on it. Mine was under the temp control. Then remove it or get the part number online and google how to buy one.