Did the HVAC person take the installation instructions? Are you having difficulties with the furnace? These are really questions for the installer. However there are restrictions as to total equivalent pipe length (inlet and exhaust) based on pipe diameter. Equivalent length is not only the length of straight pieces but also the effect of elbows on air flow. If there is too much friction you may not get the necessary air flow for combustion. The equivalent length is based on the size (BTU/hr) of your furnace, which we do not know.
Go here to d/l the installation manual and you can see the size pipe and equivalent lengths allowed for various - **/doc_details/2-xv95-trane-installation-manual.html
If this does not get into the message, search for Trane XV 95 pdf and look for a site that belongs to sbeelectricandhvac . The url will be sbeelectricandhvac 'dot' com/doc_details/2-xv95-trane-installation-manual.html This site has the manual for d/l.