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After the call to cool to the Condensing unit. It takes about 4-5 minutes for the fan in the condensing unit to start. Is this normal? or does this point to a problem with the capacitor?

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This could be normal. Depending on the installation some units will have a time delay for start up. They have the delay to prevent a quick restart.

For example if the compressor is running and turned off then immediately turned back on the current draw would be so high it would trip the breaker or overload the compressor. When a compressor turns off it needs time for the system pressure to equalize.

Most systems use some type of time delay, either built into the thermostat or into the contactor on the outside unit.

Let me know if you have questions.

Posted on May 29, 2010

  • malik81 May 29, 2010

    I was kind of hoping that it would be a capacitor or something that would narrow down the cause for the humming that I get. The humming seems to originate from the AC and transfers through the line set into the building. I have been able to attenuate the noise to a certain degree but i can still hear it inside the room and the fact that it doesnt fix the underlying cause is cause for concern for me.

  • Philip May 29, 2010


    I was unaware you had a humming noise also. If the noise is there just when the outside unit is not running then it could possibly due to the contactor not making connection.

    If it is noisy while the ac unit is running outside it could be a number of things. I will try and name a few, but most will lead back to vibration.

    -Compressor itself is working harder than it should due to dirty condenser coils out side, or worn rubber mounts that it sits on. The compressor internal bearings could be going out also causing vibration.

    - The outside unit has become unlevel causing vibration

    - The outside fan bearings are causing vibration.



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MY freezer won't start I hear it click and try but won't run . what do you think broke ? and is it cost effective to fix or just toss it and get a new one?

If it clicks periodically, let say every two minutes or so, the compressor is most probably tripping on high temperature overload due to excessive amp draw from the compressor stuck. About 50 per cent of the time the compressor has a bad start relay and or start capacitor and can be repaired with a 3 in 1 start relay which cost around 30 bucks and is available from johnstone supply. If this does not start the compressor, in most cases where the compressor still does not start, you need a new compressor and filter drier and the repair cost is going to cost as much as a new freezer. If this is a commercial freezer it is normally cost effective to go ahead and replace the compressor due to expensive nature of commerce I also freezers.
It may be possible to learn a little from what caused the failure and prevent it in the future. If your compressor discharges into a condensing coil with a fan, check for dirt and lint buildup. I have seen condensing coils that look like zz top beards. Remove the dirt and let it cool down and sometimes the compressor will restart and start running properly again.
If the condensing coil is inside the side walls and no fan then ignore the previous comment. It is advisable to clean a fan cooled unit at least yearly. Yearly cleanings allows the refrigeration system to run efficiently. This applies to all refrigeration systems.
Hope this helps!

Apr 19, 2016 | Refrigerators

1 Answer

Frig will cool but not stay cold

Check the condensing coil under the back side of the refrigerator. If the condensing coil gets dirty, the refrigerant does not condense at the proper temperature and carries unshed heat with it back to the evaporator. This excess heat reduces the ability of the refrigerant to cool because it did not lose the correct amount in the condenser. The condensing coil and it associated fan is located behind the cardboard cover on back side of the refrigerator.
The condensing coil should be cleaned at least yearly. People with pets such as shedding cats and dogs may have to clean it more often.
On your temperature control, a setting of 5 for both freezer and fresh foods section is the normal value.
Another thing to check is the air flow blockage in the freezer for the evaporator and product stored there. If the fan inside of the evaporator can not circulate air then improper cooling will occur. Make sure there is space between shelves and between product so air can circulate.

Hope this helps

Dec 08, 2014 | Refrigerators

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What should I do if alarm beeps on a Siemens refrigerator KD49NA73SA

It is probablly set up with overtemp controls. If your unit has an external condensing coil, it is probably dirty and not allowing the fan to circulate cooling air to remove heat.

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Rheem air conditioner fan comes on ,goes off ,comes on but not all of the time reaches room temp then goes off

If your description is in a few minutes, It sounds like a loose wire. If it is the outside fan motor to which you were referring, it should have 3 wires. Find those 3 wires and trace them back to the control board and main contactor. check the condition of any connections and the condition of the insulation. Next, If it is the blower motor, do the same thing.
It also sounds like it could be the control wiring. The blower control wire is the green wire coming from the thermostat and going to the fan control board in the air handler. If you have a loose connnection in the thermostat and/or loose connnection for some splice in that wire, it could interrupt the control power to the blower motor and cause it to cycle.
If it is the condensing fan on the condensing unit, it is the yellow wire. Check the same criteria as green wire above.

As far as the last of your inquiry, the air conditioner reaches temperature then turns off is normal and is not part of the problem your having.
The only other thing I can think of without more information, If the condensing unit comes on and shortly later turns off, the question is whether the condensing fan comes on when the compressor turns on. I had a case today, both the outdoor fan and compressor would not run, but the main contactor was pulled in, and voltage was available. It turns out the dual capacitor was bad and the condensing fan had stopped running and the compressor was cycling on the inherent motor protection inside the compressor. Inside the compressor is a bimetallic overtemperature switch that helps protect the compressor from getting to hot. This is your probable cause and can be determined by checking the temperature of the condensing fan motor and the temperature of the compressor. If both are so hot your hand gets burned, you probably need an new capacitor and outdoor fan motor. If the compressor cools by turning it off, the inherent motor protection will reset if it has not burned out. If after deenergizing the compressor cool off and will not reset, the compressor will have to be changed.

Hope this helps.

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Sounds like you need to clean off the fan blades. Over time the fan will build up so much dust it can interfere with the fan cooling the condensing coils. If the fan can't keep the coils properly cooled off the temperature in the refrigerator will rise. Make sure to unplug the refrigerator before cleaning the fan. Of course it could be that your condensing fan motor is just going bad (bearing etc.) If you are not comfortable checking the unit yourself contact an appliance service company.

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flushing out water lines do you mean condensate line coming off the furnace that drain to the outside. is the condensing unit outside running when u have it in cooling mode. by condensing unit I mean the unit outside that has lines that run to the inside. does that turn on when u have it in cooling. the unit outside have two components that should turn on the outdoor condenser fan and a compressor.

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Is you indoor fan running? Is the out door unit running? (Condensing Unit) If both are true, is the larger of the two copper lines on the Condensing Unit colder than the smaller one? If not, is the compressor in the Condensing Unit running? The compressor is the big can under the fan in the Condensing Unit. Please reply to this as you may need a service tech. at this point.

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be aware that not repairing this asap that you are causing yourself more problems First I would change out the fan capacitor and see if this could be the problem. Secondly if the capacitor isn,t the problem change out the motor . By continuing to allow the system to cycle like this the compressor will take a dive on you costing more . Good Luck


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