I have in my house a 5 inch chimney liner. A 45000 BTU natural gas furnace is hooked up to it with a 5" Y collar and 4 ” collar is going to the natural gas hot water tank. The tank is 40 gallons low input type.
I want to replace the tank with a 50 US gallon tank which is 45000 BTU. Is the 5 ” chimney liner sufficient for venting the furnace and the new tank? Please advise me. Thank you.