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Re: air handler fan operation
If the motor has a running capacitor check to see if it is bad. A split phase capacitor being bad will cause the motor to draw more electricity and result in the internal overload cycling the motor off. When it cools it will try again. Also check the motor for possible need of lubrication. This will be indicated by it not turning freely.
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Looking at the wall thermostat, you will see the fan switch that has two settings: fan auto, fan on.
You will need to place the fan switch in the fan on position for testing purposes.
This will make the indoor fan run continuosly, and never cycle off.
In the fan auto position, the fan will turn off when the thermostat temperature setting has been satisfied.
Remove the air handler access panel.
Is the air handler fan operating?
If the fan isn't working see if you can listen closely if it is humming, or can touch the motor to see if it is hot.
If it is humming and has a bad capacitor, you can tell this without having an electrical tester by spinning the fan wheel by hand.
Be very careful... making sure your hand won't get cut by the fan wheel spinning when it starts up.
If the fan spins and picks up full speed, replace the defective fan capacitor.
It is the shiny silver metallic cylindrical object with electrical wires attached to it.
Make sure you write down where those wires attach and turn the power off before removal as they carry 240 volts to the fan motor.
If you find that the fan wheel doesn't turn freely when you try to spin it by hand, the bearings have seized and you will need to find another fan motor of the same size, shaft length , speed , and horsepower to replace the defective motor.
Keep in mind that a humming sound in the air handler COULD be from the transformer instead of the fan motor.
The transformer is a black cube shaped device with electrical wires attached to it.
If the 24 volt transformer goes bad, your thermostat will not function and nothing will come on.
The Gibson GB5VM's ECM variable speed motor includes 12 field-selectable cooling airflows and 4 heating airflows to match any application. This Gibson air handler's quiet blower operation is achieved through extra quiet and smooth blower on and off cycles. Consult with your INSTALLATION & OPERATING MANUAL provided from your local Gibson Installation Team. If you cannot locate one, you can call GIBSON 24/7 at toll free 888-701-5040
If it is not turning full speed and no one has re wired anything, you could have a shorted capacitor. The capacitor looks like a big battery and is either mounted directly on the motor or next to the motor on the blower housing. It is is pregnant or bloated, it is shorted. If this is not the case the motor itself could have a short in the windings, resulting in a new motor
Is this a split or packaged sysyem? In a heat pump condensing unit or package unit the indoor fan motor may be delayed due to a timer or program. Otherwise you may have a weak capacitor or a bad motor. The air handler is generally a 230 v unit due to the heat strip operation, have you checked line voltage from the main breaker
Air Handlers differ in the way they adjust there variable speeds. Carrier you just plug into a pin. Trane has dip switches with directions on the fan housing. Before you try to adjust please kill power to air handler. Varriable speed are very sensative to voltage. If I new your air handler brand I could help. But just check the wiring diagram and they may ahve dirrections on there for setting speed. Need more help call back Rus
The indoor blower motor is sometimes a 3 speed motor.The heat usually works on low or medium speed.But the a/c is usually on high speed,this gives greater air flow across the evaporator coil to give you better cooling,also better air flow at ducts.These speeds are usually wired through a relay in the inside unit (air handler).They can be changed.If you go to thermostat and put the fan switch to "on" the blower should operate on "high" speed.With the fan switch set to "auto"the operation will determine the fan speed.Hope this helps. Gregg
Just take out the fan and capacitor they are not OEM so any fan motor would work as long as same Horsepower and milti speed. And the capacitor is a 5 uf or maybe 7.5. You might have to cut off the shaft of the new fan motor so it don't stick out.. You can get a new fan and capacitor at any Heating and Air parts house. And you are sure they are bad you ohmed them out? Fans are not cheap about 50-75 bucks retail. Let me know how it goes. ken