This poor GMPN-4 barely lasted 3 years. In its defense, the duct system was slightly undersized but that describes most of the new homes around here. If every other unit failed like this, we'd need 30 more companies to change them. Hopefully the tubular will hold up better on the new models.
What was the original complaint/problem? Or was it a seasonal "check & clean" PM?
janijunks earned their lousy reputation, one unadmitted problem they have had is the blower comes shipped from the factory lacking being COMPLETELY pushed back into the compartment. it lacks 3/8 of an inch from being seated completely, temp. rise will be okay but will cycle on limit, if unknown by serviceman it can be totally missed.
voice of alot of time, installs, and experience!! cringed every time the boss sold one. it will not get enough airflow thru the furnace without it being shoved all the way back. this problem probably has been corrected with the new style heat exchangers and design. no longer installing.