My Weil McClain Ultra 230 unit does not appear to receive a call for heat signal from either of the thermostadts in my house (2 zone). The thermostadts say system on and appear to be calling for heat. The indirect DHW works fine. The outdoor sensor unit was connected and even when outdoor air was <70 it did not crank out any heat. The outdoor sensor is now disconnected but still no heat. Any ideas?