<html><head></head><body><div class="ydpc71e246cyahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:16px;"><div><div dir="ltr" data-setdir="false">Hi Folks:</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">I am getting a "heat exchanger XX Sys1 UA calculation failed to converge" error. The model has three building in it and only two air handlers per building. I don't have any heat exchangers attached to the air handlers or any heat recovery installed.<br></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Sometimes the error occurs when I change the glass type via the library and other times I get the error when I adjust the air changes per hour in one or two zones.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">In the example above, the error was for system B2, but it varies...sometimes systems A or C 1 or 2.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Any ideas what the problem could be? <br></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Thank you,<br></div><div><br></div><div class="ydpc71e246csignature">Paul Diglio<br>87 Fairmont Avenue <br>New Haven, CT 06513 <br><br><br></div></div></div></body></html>