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Knocking compressor unit knocks

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Really depends on the model of compressor but if it is an oil less compressor best thing is to junk it and buy a oil lubricated with a cast iron pump dont get one with aluminum if you want a compressor to last you for many years.

Posted on Mar 24, 2014


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Fujitsu Air conditioner won't start after been off for 3 months

Knocking or hammering at the compressor is indicative of liquid refrigerant in the compressor. The compressor can't compress liquid. You'll need to call someone out to possibly evacuate and recharge the unit to remove the liquid in the compressor

Aug 09, 2016 | Fujitsu Heating & Cooling

1 Answer

My Whirlpool refrigerator makes a continuous knocking sound for about a minute or 2 then makes one louder knock and stops for a bit then does it again

Hello Barb;

My name is Peter. I am a retired field service refrigeration technician.

Inside your compressor are two flat plate valves. Unfortunately, these plates are broken. This causes your compressor to knock loudly. You can confirm this. Pull your refrigerator out. Without unplugging, remove the bottom cover. Observe the compressor. You will see the compressor jerk and jump.

It is expensive to replace a compressor. Depending on your model it can cost between $450.00 & $650.00. The rule of thumb is: "If the cost of repair is 1/3 of the original value purchase a new unit".

Sorry for the bad news.

Peter, Baltimore, Maryland

Nov 11, 2014 | Refrigerators

2 Answers

95 Buick Regal .it makes a knocking noise when running,but when I take belt off it stops.I replaced the water pump and it still knocks.

Said "knock" could be in the AC compressor or power steering unit since it don't knock with belt off.

Aug 24, 2014 | 1995 Buick Regal

1 Answer

Knocking noise about every hour or so,lasts 5 or 10 sec's. just started after 7 years .

This is the first sign of the compressor going out. You will either need to replace the compressor or purchase a new unit.

Oct 22, 2012 | Whirlpool 25.4 Cu. Ft. Side-by-Side...

2 Answers

My refrigeratro makes a knocking noise and it is getting more frequent and louder. What causes this?

The knocking noise will be from the compressor in the back of the fridge. It is a (typically) black object a little smaller than a soccer ball, situated at the bottom of the unit in the rear). It will have pipes connecting it to the hear exchanger (a black radiator that covers most of the rear of the fridge). The knocking will happen when the fridge is in a cooling cycle and the compressor is running.

There are 2 reasons for the compressor to "knock":

1) It is positioned on rubber mounts and one of these may have become dislodged if the fridge was moved recently. Or one or more of the mounts may be worn, or the compressor may have been slightly moved by something and is knocking on another component or the chassis of the fridge. It may be simple enough to check this out and move the compressor on its mountings slightly to aviod the knocking.

2) Far worse, the knocking may be from an internal component in the compressor. Sadly, this is a sealed unit and while it is possible for a professional to replace the compressor and then re-gas the fridge (Re-fill the coolant gas that will escape when the compressor is removed), the cost of doinf this will probably mean that the fridge is beyond economical repair.

Aug 30, 2011 | Amana ABB1927DE Bottom Freezer...

1 Answer

Knocking noise coming from bottom of refrigerator

check the compressor for operation adn check the fan in the back of unit to make sure it is running...whirlpool units are notorious for compressor relay failure normally they click in and out every few minutes... if it is a knocking noise and continuous make sure compressor is not trying to start and sitting there shaking... normally it will stop after a few minutes and then start again....

Jan 25, 2011 | Whirlpool GS6NBEXRS Side by Side...

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Knocking sounds like something is knocking on the door


The knocking could be the damper if it last for about 5 seconds when the compressor turns on or off, or it can also be the refrigerant gassing off in the evaporator this sound can be really intermittent, but is normal with the refrigerants used today. However the compressor you see is actually the outer shell, inside of which is a refrigerant pump (i.e.: compressor) which is on internal support springs. When the unit turns off, the momentum of the internal parts can sometimes knock against the outside of the compressor case. The only "fix" would be a new compressor. However this does not actually indicates compressor failure and most likely will run many more years with no problem.

Please get back to us if you have further query else please accept the suggestion.

Thank you for contacting

Jan 03, 2011 | Refrigerators

1 Answer

Knocking Noise?

Might be the compressor. It would be a good idea to shoot it with some compressor oil.

Apr 20, 2009 | GE Zoneline AZ55H07D Air Conditioner

1 Answer

New 14 seer split ruud heat pump makes very loud knocking noise

Well you may want to have a tech come out and check the freon level, but mostly when going into defrost, some units make alot of noise, the freon is reversed in the unit by way of the reversing valve, it makes a whooshing sound like freon is draining off, as far as the knocking noise, could be as I said in the beginning, might be low on freon, but it could be that, this particular unit does this, I have had units make some really strange noises in the past but functioned perfectly, hope this helped, please let us know, thanks again,

Jan 24, 2009 | Ruud UAMB Air Conditioner

3 Answers

Amana refridgerator mdl abl2222fes knock noise

sounds like the compressor vibration dampers are wearing out. the dampers are the rubber washers that seperate the compressor from the chassis of the fridge. when they start to deteriorate, and the compressor kicks on, it will bounce against something in the chassis, causing a knocking noise.

Jan 22, 2009 | Amana ABL2222FES Stainless Steel Bottom...

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