| Either you are incredibly fortunate, or we just happened to get a lemon.
I had one installed in 94. The first failure was the tuning valve (seal
leaked). I noticed the water dripping onto the floor of the burner compartment
and dribbling down onto the blower. At that time the unit was covered by a
maintenance plan with a spinoff of the gas supplier. They had been quite
helpful with the previous furnace, but they didn't seem to want to deal with
this one. The tech first tried to claim that dripping water is normal for
high-efficiency furnaces. Then he said he would replace that part. A few days
later he called me to ask if I knew a contact number for Bryant(!). I gave
him the 800 number, but I never heard from him again. Needless to say we
didn't renew the maintenance plan. Fortunately I was able to order a new
tuning valve (it's really just an adjustable cap) online. I still have the
old one and I may try to rebuild the seal at some point.
The next failure was the internal drain tubes. They rotted out and started
leaking more water onto the floor of the burner compartment. I couldn't find
any specific replacement part for them so I used some transparent high-temp
tubing similar to what I've seen in other brands of condensing furnaces. The
original tubes were a black plastic/rubber that was more flexible but seemed
to be attacked by the condensate and reduced to goo.
The next problem was a failed hot-surface ignition module. This was replaced
by a service technician; however, I was a little curious about why it had
failed so I watched the furnace carefully for a few days. This brings me to:
The next problem was in the control module. I observed that the furnace
was cycling constantly when the thermostat called for heat. The burner
would fire ok, but it would shut off even before the fan-on delay time.
Then the fan would come on and run until the fan-off delay. Then (if the
thermostat was still calling for heat) the burner would fire again and
the sequence would repeat. Obviously this put a lot of stress on the hot
surface module. The control module was not indicating any error codes and
I eliminated the obvious causes (pressure switch, high-limit, flame sensor).
To make a long story short, the problem was some failed solder joints on the
control module's PC board. The load resistors for the thermostat loop are
mounted a little off the board and soldered to grommets, but apparently not
isolated well enough. The constant temperature cycling had broken the bond
and allowed the connection to open when the resistors became warm during a
call for heat. I soldered the joints a bit more completely and they have
been ok for a few years. Note that Bryant eventually admitted to this problem
and supposedly had some sort of free exchange program, but it was unclear to
me (and to my service technician) how one might take advantage of the program.
The next problem was the blower motor. It started making horrible noises
and caused the whole furnace to vibrate. The technician had a lot of trouble
replacing the motor because the shaft had corroded to the fan cage assembly.
(He used up all of my Dremel cutoff disks removing enough of the shaft to
accommodate his clamp-on pulling tool. :) I suspect that the difficulty
and the failure itself were caused at least in part by the previous leaks.
Lately the inducer motor has been making a terrible noise and vibration on
startup. Once (if) it gets going it seems to be ok for a while. I suspect
it will have to be replaced soon, though...