EBC10P/E is hunting

This occurs if the fan speed on the EBC10 is set too low to make the pressure switch. The control will ramp the fan up to 100% output and if the pressure switch closes, then ramp back down to the set speed. If the pressure switch opens again, then it'll ramp the fan up to 100%. If the pressure switch closes, then it'll ramp back down to the set speed + 10%. It will repeat this cycle until it settles to a fan speed that will keep the pressure switch closed. Once the call for heat is removed and reapplied, it will go through this cycle all over again until the fan speed is increased enough to close the PDS switch.