Hi everyone great site. I am just an average Joe that has just purchased an OWB and is presently in the installation process. I have a boiler which is a pressurized system, heating my residence with hot water baseboard. My dealer said to depressurize the sytem and install the OWB direct. But in reading this forum I will install a Hx it makes sense. I then told my dealer my intentions and he says that I will need an extra pump on the boiler side of the Hx because if I use the pump that's on the boiler now it will only turn on when there is a call for heat, and the water inside the boiler may not be hot enough at the beginning of the cycle in which case the oil boiler would turn on . At least that is what I understand. So my question is is he right and would that extra pump have to constantly be running. PS quick install diagram would be apriciated theres is pretty vague. Thank you much!