I have a four year old Bryant Evolution Extreme 280A heat pump. The variable speed fan has recently started sputtering. By this, I mean it will come up to speed, then shut off, then maybe start turning again, then slow
down to a crawl (1 revolution per second), etc. Eventually, after 5-10 minutes, it seems to recover and run normally. It definitely is not in Defrost mode when this is happening. It is like there are certain narrow RPM ranges
that the motor can't seem to do correctly.
The Bryant installer came out and took a look, but it was operating normally while he was here. He didn't believe me that the fan stopped or slowed down and told me that the unit must have been in Defrost. I know what
Defrost mode is and the unit was not in it. In fact, I happened to be standing there earlier in the day when it came OUT of Defrost, and that's when I noticed the abnormal fan. Then he tried to tell me that it supposed to
work that way and that the fan can stop in normal heat operation. I don't think so!
Anyway, same thing happened the following day, but this time I took a video. When a different tech came, the system actually misbehaved while he was there and he agreed that something was amiss. He called Bryant who
gave him authorization to replace the motor under warranty. After the replacement, it seems to run perfectly fine now.
But here's the rub: I am a ham radio operator and I noticed from the very first day this system was installed four years ago, I get terrible interference on my radio when the fan is operating (noise spikes every 18 kHz). And
I know it is the fan, since when the heat pump is in Defrost mode, the noise stops. After they replaced the motor, all the interference is completely gone!
So I'm wondering whether the original motor was actually defective from the factory and it simply took four years to degrade to the point where it malfunctioned. Anybody out there familiar with the circuitry inside the
ECM? I'm guessing a bunch of capacitors, diodes, MOSFETs and control ICs. Anyone care to speculate what went wrong?
down to a crawl (1 revolution per second), etc. Eventually, after 5-10 minutes, it seems to recover and run normally. It definitely is not in Defrost mode when this is happening. It is like there are certain narrow RPM ranges
that the motor can't seem to do correctly.
The Bryant installer came out and took a look, but it was operating normally while he was here. He didn't believe me that the fan stopped or slowed down and told me that the unit must have been in Defrost. I know what
Defrost mode is and the unit was not in it. In fact, I happened to be standing there earlier in the day when it came OUT of Defrost, and that's when I noticed the abnormal fan. Then he tried to tell me that it supposed to
work that way and that the fan can stop in normal heat operation. I don't think so!
Anyway, same thing happened the following day, but this time I took a video. When a different tech came, the system actually misbehaved while he was there and he agreed that something was amiss. He called Bryant who
gave him authorization to replace the motor under warranty. After the replacement, it seems to run perfectly fine now.
But here's the rub: I am a ham radio operator and I noticed from the very first day this system was installed four years ago, I get terrible interference on my radio when the fan is operating (noise spikes every 18 kHz). And
I know it is the fan, since when the heat pump is in Defrost mode, the noise stops. After they replaced the motor, all the interference is completely gone!
So I'm wondering whether the original motor was actually defective from the factory and it simply took four years to degrade to the point where it malfunctioned. Anybody out there familiar with the circuitry inside the
ECM? I'm guessing a bunch of capacitors, diodes, MOSFETs and control ICs. Anyone care to speculate what went wrong?
source https://hvac-talk.com/vbb/showthread.php?2225795-Heat-Pump-ECM-Issue&goto=newpost
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