[SOLVED] Help with 1960 GE Forced Air Gas Heater

I must have missed from your earlier post that your Amana is actually a 90% efficient furnace, I was under impression that it is an 80% which would have made the vent sharing OK. It is not the case though.

It is a condensing type gas furnace that cannot have a B, BW or L type vent or vent connector. The pictures of the furnace didn't make it through (yet) but I think B is the type you have. This is straight from Amana service manual on 90% furnaces:

<q>A condensing gas furnace achieves its high level of efficiency by extracting almost all of the heat from the products of combustion and cooling them to the point where condensa- tion takes place. Because of the relatively low flue gas tem- perature and water condensation requirements, PVC pipe is used as venting material. This furnace must not be connected to Type B, BW, or L vent or vent connector, and must not be vented into any portion of a factory built or masonry chimney except when used as a pathway for PVC as described later in this sec- tion. Never common vent this appliance with another appli- ance or use a vent which is used by a solid fuel appliance. Do not use commercially available “no hub connectors” other than those shipped with this product.</q>

See the picture I attach below for the venting arrangements they do recommend.  One other possible venting design is to use an unused masonry chimney as a chase for a PVC vent for your 90% Amana and a separate B type vent for your old GE and the water heater. That will also eliminate your concerns about the lining of the chimney.

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Posted 5 years ago by homeowners in Heating

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