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Where are you taking the readings? And you have to use the Single Zone thermostat with that control box. You should be taking a reading between the positive and negative leads on the back of the thermostat.
We have no way of knowing if this is "your first rodeo" or not. We always have the customer check. I suspect you will just need to call in a mobile tech or take it into the shop. This format works only when the customer can supply some needed information and follow some simple directions on testing. Sorry it didn't work our for you!