Hi Cwfacesetc,
Certain types of fossil fuel burning appliances can share the same vent pipe; it is a very common type of installation. However, there are several important rules that must be followed while configuring such venting system and you can find all that information in “
HVAC” category after returning to my website.
If you have some specific questions about your installation, please provide detailed information about your chimney (material, interior / partially exposed), brand and model of your appliances, their BTU's (should be listed on their nameplates), distance between the appliances and the chimney.
Just click "comment" below.