Fireplaces, Heating Stoves, Flues and Chimneys - Fireplace replacement

We currently have an existing wood fireplace (not sure of the brand) with triple wall chimney pipe. I would like to have a new fireplace installed but have been getting different information from local retailers. One place I visited said that I wouldn't be able to use the triple wall chimney with any new fireplaces since everything fits to double wall now. Another place mentioned something similar but also noted that it's more due to the connection to the fireplace itself- stating that each fireplace manufacturer has their own method of connecting the pipe to the fireplace. They mentioned that the only way I "may" be able to use the existing pipe would be to find out what brand the fireplace is and check to see whether the manufacturer still makes fireplaces that fit that pipe. Although I'm not sure what brand it is yet, the type of fireplace we have is similar to a Healtilator A36R. I've also found a triple wall to double wall adapter for a particular brand of fireplace. I'd really hate to waste the triple wall pipe if it can be used, not to mention the money that would be saved. Any advise would help greatly.

Hopefully you live where there is a hearth store that sells nothing but stoves. They know their business. Hardware stores, big boxes, and other stores that sell stoves as a sideline, do not know stoves. Hearth stores can recommend a certified installer. Each manufacturer has its own specific installation instructions for each of its models. Even so, the installation must meet the requirements of local building codes. Triple wall chimneys are typically used with zero clearance fireplace inserts. Triple-Wall Metal Chimneys for Fireplaces: Diagnosis, Cleaning & Repair Guide (http://inspect-ny.com/chimneys/Metal_Fireplace_Chimneys.htm)