The installation work was carried out on May 15, and the item purchased three bottles was placed in hot water at 54 ° C, and one of them was instructed at 48 ° C, with a difference of 7 ° C. Please ensure the quality control of goods firmly before shipping. I will purchase items from the same manufacturer but please do not have it twice. Also, the thermometer in this product has a lot of play, but is there a cause for this temperature difference here? Please contact the manufacturer and contact us as soon as possible. If there is a possibility to fix it please tell me how. Depending on the contact, we will process returns.