Solar Hot Water Parts has a wide range of solar hot water sensors. The most common mistake that people make is to think that all sensors are the same. There are many different types of thermistors and resistors used in making solar hot water sensors. Roof sensors should only be used in the solar collector. Tank sensors cannot be used as roof sensors as they are rated to lower temperatures. Please contact us if you need help or you are unsure of what you need to purchase. Email us some photos of what you are looking for, as this will help ensure you provide the best possible information.