Is 5.5\" flue liner ok for boiler w/ 6\" flue collar?

Steve M_2

Atmospheric Draft boilers are so 1960's. Do yourself or your customer a favor and install a mod/con boiler. Utilities are going to keep going up and it will pay for itself in savings and comfort and solve your venting problem.

Metal Fab is the only brand I've worked with and you need to do the math according to their specs. Local codes may apply as well.

Mike Kehoe_4

Ok to use 5.5\" flue liner for boiler with 6\" flue collar?

On a website for a flue liner manufacturer, it said that in instances where a chimney is too small to fit a 6" liner, it is usually ok to use a 5.5" liner as long as the chimney is at least 20' high. Anyone think differently? Thanks!

A.J.

liner size

It depends on your efficiency,input and chimney height.I have gone as low as 5" on a small three section boiler. Talk to somebody that has experience with sizing liners.

Home Depot Employee

That would depend on the appliance(s), BTU's, interior or exterior chimney, vertical connectors and chimney height.

Only a sizing chart from the manufacturer will tell but, 5.5" liners regardless of the draft hood size will work well if it fits within the range of the chart.