Customer only having an issue with the new installation. After extensive diagnostics I found that a roof cap on the exterior of the building had fallen against the flue pipe. I went on the roof and raised it up and tightened the clamp. These concentric caps are not the right ones and Installation manager to follow up with the customer regarding replacing both of these caps to the correct cone style cap. However the unit is operating normal at this time. I left it running on high stage heat while I began packing up my tools and there are no more pressure faults. I also spoke with the Installation manager to verify warranty status for this call. This is technically not related to the installation of the equipment but I was given the okay to warranty the call as a courtesy for some of the other installation issues.