I want to second this. Separating the wifi from the router and getting dedicated devices improved performance greatly over having a "jack of all trades" router/access point. I just deployed probably these same access points Tuesday at my house and strength of the wifi is about 60%-75% better...
If it is a stick/probe type thermometer it likely has an adjustment nut where the probe meets the dial. Most commercial thermometers are adjustable and should be calibrated every so often as they can get off as they are bumped and knocked around. If you post a pick I would be able to tell for...