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Cruise Air Blower Fan Buzzing
I have a Cruise Air that when it’s first turned on, the fan blows on high, and sounds normal, but as the temperature gets closer to the “set” temp, and the fan should slow down, it doesn’t, and as the LED indicator on the fan shows less speed, the fan doesn’t slow down, and it makes a buzzing sound which gets louder, as less fan speed is required.
I can lower the temp, which causes higher fan speed, and the noise goes away…….until it gets close to the setting, and the noise starts again.
Sounds like an electrical buzzing? Any clues as to what to look for?
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9 Replies
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Donnie Myers told me that the SMX controller is not a inverter but just lowers voltage to reduce fan speed which will only work for so long and then the situation that you have will occur.
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I’ll try swapping the SMX out with another, what is the procedure for removing them? How are they attached to the wall? I guess the wiring will unplug?
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It’s easy Jerry, there’s a plug on the back of the SMX, just remove it and swap out.
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I checked into this for my units. Low speed buzzing of the evap motor is probably caused by the power module and/or a weak run capacitor and not the controller. Looks like the speed is controlled by a TRIAC. Here is what I did. You can avoid the low speed buzzing by programming a higher min speed in the SMX controller. The manual explains how to enter programming mode. Or you can set the fan speed manually and avoid the very low speed modes.
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Yea, I have manually set the fan speed to high, noise stops, but fan is wide open all the time, whether cooling or not. Guess I can’t have everything.
What is the process for removing the SMX control panel from the wall?
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Jerry, page 10 of the manual shows how to set intermittent fan. Perhaps if you do this and set the minimum speed higher it will solve your problem. Here is a link to the manual.
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Typically, you don’t need to run it on high. For me it was sufficient to reprogram min fan speed to the 2nd or 3rd lowest. Much better than the buzzing//groaning on the lowest speed and it still reduces speed when it hits target temp.
What is happening is the controller sends a command to lower speed to the power module which reduces the voltage to the motor via a TRIAC. As it cuts out more and more of the wave form, the motor starts buzzing. Probably because of a marginal run capacitor. Caps do age/fail over time.
TRIAC controlled speed will always produce some hum at the lowest speed settings. The fan should be set in rubber bushings to minimize the hum. The bushings in our older units are probably shot.
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ok, I’ll take a look at resetting it. thanks
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