as has been noted, Pulse furnaces are no longer supported by Lennox. What parts are in stock, if any, is all that exists. If you do need a part and it is on the open market, it will cost you!!!
I would not retrofit anything into a Pulse, even if I got it at wholesale.
Have HX pressure tested and use the money you are willing to put into it along with the credit Lennox gives towards a Pulse replacement and get a new furnace.
The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
from an excerpt by Paul Jacob in Sun City, AZ