I have an AO Smith GPSH 50 100 power vent water heater that I will need to replace. Do I need to replace it with another power vent heater or can I get a non power vent water heater? (This has a PVC vent now, can I use the PVC if I get something else?)
A conventional gas water heater cannot use a PVC flu pipe, it can only use steel, if you wish, to run a steel pipe up through the middle of your house you can do so, but if I were you, I would just get another power vent water heater and hook it up to the existing flu.
A conventional WH's exhaust it too hot and would burn, melt, or distort PVC. And, you will find that, depending on the model, you may not be able to reuse what you have since it might require a different size, or have restrictions on the length and/or amount of elbows, etc. that are in your existing run. Each model will have a max run length and pipe size set of requirements...IOW, they are not all created equal!
You need to read the installation instructions carefully, or solicit a good plumber to ensure you have a safe installation.
Thanks very much for your feedback. The existing WH is an AO Smith that I've read many negative comment about it being a dog... Has AO Smith's quality improved so I should consider another AO Smith or is there another brand I should look at?