Lining your chimney

[Johnny]

For those of you wondering whether or not you should reline your chimney when installing hi efficiency furnaces. Please read the instructions for the furnace carefully 3 or 4 times if need be. It states clearly in 99% of them the need for a corrosion resistant metal flue liner sized as per ansi z.2331 in national fuel gas code. Their should be no debate after this easy inquiry, that is if your families safety is of any concern to you. Listen folks it may not be cheap but it sure as heck isn't expensive enough to neglect. We are talking about carbon monoxide in the Flue gases. Other codes like NFPA 211 expound on this too, so do your homework and be safe.

[CBHvac]

Ummmm.....

Also, most new HIGH efficentcy furnaces will NOT vent through the chimney, but through a 2 inch PVC pipe, and will also pull combustion air in through a 2 inch PVC pipe.. Of course, we no longer install 80% units at all, and replace all units with

90% or better, so none of my customers worry about liners anyway..

[Johnny]

Some high efficiency furnaces vent through pvc and therefore don't require natural draft.

Those that do require natural draft require Flues(chimneys) capable of eliminating the carbon monoxide from the dwelling. Hence the NFPA ,National fuel gas code and Manufacturers of Gas furnaces state the necessity of a Flue that is sized correctly and will resist softening and corrosion due to the nature of the flue gas. The high efficiency furnaces that mechanically force flue gase through pvc have a whole set of requirements that also must be followed as per national fuel gas code, NFPA and manufacturers info. It is important that they not be confused. Most residential dwellings in the NE U.S. have heating systems that require natural draft. You need only look around in this region to note almost all houses here have at least one chimney. This is because in colder climates houses need to be versatile enough to utilize different fuels. Solid fuels like wood or liquid fuels like oil and gas have appliances that traditionally rely on natural draft to vent their exhaust and for good reason. Natural draft has no moving parts and when chimneys are constructed properly they can last indefinately. Not so with mechanical draft systems which have a life expectancy that varies but never exceeds the life of the appliance.

[Jim K]

[xymergy]

Jim is correct in my experience in western New York; my new York (your brand!) furnace vents outside the basement wall via a PVC pipe, and my

1998 Sears gas water heater continues to vent up the chimney via a newly installed liner. The liner cost me $350, if I recall correctly, and it was pretty long, on the order of close to 40 ft.

[xymergy]

No, we understood totally about the furnace; our point is that we still need to vent our water heaters, and we use the existing configuration (venting through the big old chimneys, which the old furnaces used to do, but the new 90+% ones do not), but modified slightly to include a liner to make the space smaller and protect the masonry.

So, we needed liners for our chimneys which remain in operation for the water heaters only; our furnaces vent as you describe, with new intake/exhaust PVC installations. But let me just reiterate: liners needed for the 90+% furnaces, no. Liners needed for the water heaters, yes.

[CBHvac]

Also, since this one popped back up, I might add that all the York line over

80% is what we call a condensing furnace..meaning, there is a condensate drain IN the heat exchanger, and in the vent flue, IF it has any horizontal travel at all....