Upon arrival for service call on 2019 Comfortmaker furnace, customer stated furnace was just blowing cold air. Found furnace locked out on code 3. Found furnace shutting off after 30 seconds when low pressure switch kicked in. Found exhaust not properly sloped and collecting water. Customer had just added insulation under pipe which caused a droop. Removed insulation and advised customer that based on size of furnace and length of run, furnace really needs 3” pipe. Customer is going to hold off on replacing and see how furnace runs and if there are any other issues.
