Bryant 95s strange behavior - DoItYourself.com Community Forums (2024)

02-04-16, 10:52 AM

In our new (to us) home, we have a Bryant Evolution 95s natural gas furnace that did something strange last night. Before bed, I noticed that the room temp was 64, even though the stat was set for 70. The furnace was not running. I checked the status lights on the furnace control board & found one amber light lit (not blinking). Unsure of the meaning of that, I cut power to the furnace for a minute, then turned it back on. No change. I then went back to the thermostat & moved the fan switch from AUTO to ON. That did bring the blower on. I then set it back to AUTO, and moved the mode switch from HEAT to OFF. After ten seconds, I moved it back to HEAT, and the furnace fired back up normally.

The furnace is six years old, spotlessly clean inside & out, and it's a quality installation. The inducer did conk out a couple of months ago, but that was replaced under warranty, and has been working fine.

Any ideas?

Thanks,
Andy

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02-04-16, 12:42 PM

Not enough information to even be able to speculate.

Take the cover off the burner compartment of your furnace. Turn up the thermostat and observe and understand the SEQUENCE of events which occur before you get heat.

The next time this happens, go down to the furnace and see how far the furnace is in that sequence.

Hint: When the thermostat calls for heat, the first thing you should notice is that a small motor called the inducer motor should start up and come up to speed.

If that doesn't happen, the thermostat may not actually be switching on the furnace, the furnace circuit board may not be turning on the inducer motor, or the inducer motor may be bad and not turning on properly despite having the proper power to it.

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02-04-16, 04:00 PM

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02-04-16, 05:19 PM

You didn't leave the model number so this is a generic guide. I believe amber light on means ok and not calling for heat. The green one would also have to flash for a fault. Your furnace stores codes that can be retrieved. It's covered in this service brief.

hvac partners/docs/1009/Public/0D/SM355CAV-01.pdfDoes your furnace have a hot surface igniter or intermittent pilot ?

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02-05-16, 06:39 AM

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02-05-16, 01:15 PM

>

Intermittent problems are the bane of repairman ----and DIYers too.

What you can do is to turn up the thermostat repeatedly until the furnace fails to ignite properly again. You need to be down at the furnace observing the sequence of operation when that happens.

It might take 20-40 cycles before that fails again.

Generally speaking, intermittent problems continue to recur with increasing frequency until the part going bad quits completely. So the problem, whatever it is, will probably be back.

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02-13-16, 09:49 PM

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