Tricks to free a "Stuck" compressor

[_HL4E_HalfLife_]

Theres a brand new 12000Btu A/C at the shop where i work the customer brought it back when he called up and said it wasn't working so it was brought back to the shop and he was given a replacement A/C. This ac thats not working has been opened up and has been narrowed down to whats called as a "stuck compressor" its not damaged or wired up wrong or anything like that whats going on is the bearings are tighter than normal and is preventing the compressor from reaching full speed but all hope isn't lost when power is applied to it, it does turn but slowly only about 200 to 300rpms by the sound of it and does draw LRA but thats not enough to get the oil moving and up into the slots where the bearings are. So what are some tricks that might be able to get this compressor up to speed? I've tried the following with no luck:

Switch the run cap (15mf) with a high mf start cap (the one i tried was around 108mf)

I tried switching the cap to the run winding.

I have yet to try wiring up the compressor to 240v for 2 or 3 seconds.

Anyone know anything else that might work?

[pythagoras]

Have you tried running it backwards?

Regards

John.

[_HL4E_HalfLife_]

Have you tried running it backwards?

Regards

John.

its a 115v 1PH compressor as far as i know it can't be reversed. Its big 3 phase compressors than can be reversed.Besides reversing it isn't gonna do any good because it only picks up the oil in 1 direction.

[pythagoras]

Put the capacitor in series with the run winding, that will reverse the rotation. But only do it for 1 or 2 seconds.

Regards

John.

[pythagoras]

Ahhh you already tried that :mad: It would be running in reverse if it was in series and it was moving.

Regards

John.

[_HL4E_HalfLife_]

Put the capacitor in series with the run winding, that will reverse the rotation. But only do it for 1 or 2 seconds.

Regards

John.

If that reverses it than i already tried that it just does the same thing runs real slow drawing LRA and like i said it will only pick up the oil if its rotating the right way. I might try putting a run cap and a start cap on at the same time see if that helps.

[_HL4E_HalfLife_]

Ahhh you already tried that :mad: It would be running in reverse if it was in series and it was moving.

Regards

John.

LOLOLOL

[wdrzal]

you have a tight compressor, not much more you can do if its a hermetic.Souds like you tried all the tricks.

pythagoras your getting to be a expert !!!!

[wdrzal]

LOLOLOL


don't laugh at pythagoras thats how you reverse a compressor.YES a single phase can be reversed.

[_HL4E_HalfLife_]

you have a tight compressor, not much more you can do if its a hermetic.Souds like you tried all the tricks.

pythagoras your getting to be a expert !!!!

Its a rotary. Window A/C's don't use hermetic's (recipricator) anymore at least not around here.

[pythagoras]

Maybe a lost cause, but try forward then backwards 3 or 4 times if that dosnt free it your only left with the 240v option, send it to me and I could do that :p:

Or stick that start cap in parallel with the run cap not instead of it.

Regards

John.

Walt you'll make me blush!

[_HL4E_HalfLife_]

Maybe a lost cause, but try forward then backwards 3 or 4 times if that dosnt free it your only left with the 240v option, send it to me and I could do that :p:

Or stick that start cap in parallel with the run cap not instead of it.

Regards

John.

Walt you'll make me blush!


Hehe nice try pythagoras but theres a 240v breaker box at the shop for test running 240v ac's etc. I'd really like to get this thing going because im almost 100% sure the compressor is being replaced under warranty so the old compressor or in this case the new compressor just gets thrown out thats where i come in and bring her home :D.


Edit: Just a thought.. what about one of those hard start kits? or is that just the same as using a high mf cap?

[wdrzal]

better check the definition of hermetic, if its enclosed in a housing (can) its a hermetic ,no matter if its a piston or rotary or scroll.

[pythagoras]

All the rotary compressors I have seen have been hermetic, although I'm sure there are semihermetic ones about. What do you think a hermetic compressor is?

Regards

John.

Edit: you beat me to it :p:

[wdrzal]

if its running slow and your sure your wiring is correct it has tight bearings more than likely, it may losen up by running it, but the windings may be destroyed first depending on how thight it is.

ps try putting some extra oil down the discharge in case the piston is tight this may help to lubricate the walls. watch it will spit it out, but see if that free's it up at all

[pythagoras]

Have you tried that 108 cap in parallel with the run cap yet:?

Regards

John.

[_HL4E_HalfLife_]

Have you tried that 108 cap in parallel with the run cap yet:?

Regards

John.

No all i did was replace the 15mf run cap with the 108mf start cap but not in parallel.

[matttheniceguy]

I don't really know much about compressors, but you were saying it wasn't going fast enough to lubricate one of the bearings? This might be a stupid idea, but what about flipping it upside down and side to side etc. to try and coat everything with oil. I have no idea if that would actualy do anything, but it's worth a try I guess.

[_HL4E_HalfLife_]

I don't really know much about compressors, but you were saying it wasn't going fast enough to lubricate one of the bearings? This might be a stupid idea, but what about flipping it upside down and side to side etc. to try and coat everything with oil. I have no idea if that would actualy do anything, but it's worth a try I guess.


U know something i have thought about trying that, actually i kinda forgot about posting that idea on here.

[pythagoras]

ps try putting some extra oil down the discharge in case the piston is tight this may help to lubricate the walls. watch it will spit it out, but see if that free's it up at all

If its a rotary it wont have a piston, and I'm not sure wher the bearings are located on a rotary compresor.

Regards

John.

[wdrzal]

lol wasn't paying attention, rotarys don't have pistons, but the walls need lubercation.just got a great deal on ebay.I had to snipe it.

[wdrzal]

this is a oil vac I just won for 16.09 I already have another . it has a vacuum pump and 2 vacuum canisters ( like the ones in hospitals but a little larger.) It for sucking oil out of compressors. It works great for other things too, from bleeding brakes to putting a tube down the fill pipe of transmissions to drain the oil without removing the pan.the pump is oiless nd does not pull a deep vcuum for evcution.

you can make one with canister from a hospital and a vacuum pump. I seen 1200 cc canisters on ebay, the ones with the pump are 2000 cc but the 1200cc ones are fine.

[_HL4E_HalfLife_]

If its a rotary it wont have a piston, and I'm not sure wher the bearings are located on a rotary compresor.

Regards

John.

john go to my cascade thread i posted a rotary there apart im kinda surprised u havn't seen the pics yet :nono:

http://www.xtremesystems.org/forums/showthread.php?t=62280&page=12&pp=25

[IYP]

A tight compressor is caused by moisture, dirt, or impurities getting into the system that causes scoring of the compressor piston walls. Moisture getting into the system can be caused by not evacuating a system with a vacuum pump when it was installed, letting air into the system, or improper refrigerant charging practices. This would include not purging the refrigerant hoses before hooking them up to the unit. The compressor has a piston and piston walls just like a car. If the walls get scored then this causes a tight compressor. The refrigerant carries the oil in the system if the compressor does not get enough oil, (low refrigerant charge) this could cause scoring of the walls. This could also occur due to age, wear and tear. Some of the old compressors will get tight. This is why it is important to get a HVAC contractor who practices good refrigerant charging techniques. When a refrigerant system is opened up both suction line and liquid line filter driers should be installed and the system should be evacuated with a good vacuum pump.

[_HL4E_HalfLife_]

A tight compressor is caused by moisture, dirt, or impurities getting into the system that causes scoring of the compressor piston walls. Moisture getting into the system can be caused by not evacuating a system with a vacuum pump when it was installed, letting air into the system, or improper refrigerant charging practices. This would include not purging the refrigerant hoses before hooking them up to the unit. The compressor has a piston and piston walls just like a car. If the walls get scored then this causes a tight compressor. The refrigerant carries the oil in the system if the compressor does not get enough oil, (low refrigerant charge) this could cause scoring of the walls. This could also occur due to age, wear and tear. Some of the old compressors will get tight. This is why it is important to get a HVAC contractor who practices good refrigerant charging techniques. When a refrigerant system is opened up both suction line and liquid line filter driers should be installed and the system should be evacuated with a good vacuum pump.


Interesting but not valid here the A/C in question is brand new and has not been serviced. and im not sure if that piston thing works with a rotary since they don't have any.

[_HL4E_HalfLife_]

Well i was at work today for a bit and i was right the compressor is being replaced under warranty so im getting the old one once the replacement arrives than the fun of getting it up to speed begins :D

[LostInSpace278]

Have you tried applying heat? Let say a heat lamp.

The heat will cause the bearing housing to expand slightly, this may give you enough clearance for the bearings to work properly. Worth a try!!

[IYP]

thats a good idea with the heatlamp....should work...id give it a try...even a hair dryer might work if you dont have a heat lamp

[wdrzal]

you can wire a 250 watt light bulb plugged into a 120 volt wall outlet, in series across the run and common terminals,(the bulb works as a resistor) you should end up with 30 volts going thru the run windings. This will warm the compressor up without harming it.

Have you checked the windings with a megohmeter? if it running slow and Hummmm's louder than normal, you may have bad windings.

[Unknown_road]

you can wire a 250 watt light bulb plugged into a 120 volt wall outlet, in series across the run and common terminals,(the bulb works as a resistor) you should end up with 30 volts going thru the run windings. This will warm the compressor up without harming it.

Have you checked the windings with a megohmeter? if it running slow and Hummmm's louder than normal, you may have bad windings.

voltage is over the windings current goes thru. :toast:

[wdrzal]

voltage is over the windings current goes thru. :toast:


What are you talking about? explain!!!

[IYP]

you can wire a 250 watt light bulb plugged into a 120 volt wall outlet, in series across the run and common terminals,(the bulb works as a resistor) you should end up with 30 volts going thru the run windings. This will warm the compressor up without harming it.

Have you checked the windings with a megohmeter? if it running slow and Hummmm's louder than normal, you may have bad windings.


clever thats a good way to get things done :toast:

[Unknown_road]

What are you talking about? explain!!!

haha it is just something my professor electrical engenering kept wining about. You said voltage goes tru the windings but that is not accurate. a voltage is a indication of a difference between 2 points. It doesn't go anywhere ;)

[wdrzal]

A volt is the electromotive force (pressure) needed to move one ampere thru a one ohm resistance.

MOVE, is the relivant word here, if you have volts you have current..... you need a new professor.

[shinymod]

sorry walt but he's right.. voltage is defined as potential difference between two points. strictly speaking you should say "30 volts across" or "blah amps through"

[_HL4E_HalfLife_]

Wouldn't applying heat to the compressor make it even worse?? I say this because just last week at work theres was a call at a hotel about a beer fridge not cooling so i went there and found out the compressor was seized and was hot and tripping on its overload and drawing LRA nothing i tried could get it going again so i called up the place that sells this brand of compressor and they had them in stock and would arrive the very next day. When it did i picked it up and took it over to the hotel and buy than the compressor had cooled down so just out of curiosity i plugged it back in and sure enough the compressor took right off no problem and was working good and even sounded good.In the end this compressor was still replaced ( i got the old one now in series with the other 2 compressors i use as a vacuum pump :D)

My point of this story is that heating up this stuck compressor would only make it worse, if anything shouldn't i chill it down to like 0c or something?

[dippyskoodlez]

Wouldn't applying heat to the compressor make it even worse?? I say this because just last week at work theres was a call at a hotel about a beer fridge not cooling so i went there and found out the compressor was seized and was hot and tripping on its overload and drawing LRA nothing i tried could get it going again so i called up the place that sells this brand of compressor and they had them in stock and would arrive the very next day. When it did i picked it up and took it over to the hotel and buy than the compressor had cooled down so just out of curiosity i plugged it back in and sure enough the compressor took right off no problem and was working good and even sounded good.In the end this compressor was still replaced ( i got the old one now in series with the other 2 compressors i use as a vacuum pump :D)

My point of this story is that heating up this stuck compressor would only make it worse, if anything shouldn't i chill it down to like 0c or something?

I think they were talking about exploiting the fact stuff expands when its hot.. and when it cools it shrinks... just what you just proved ;)

[_HL4E_HalfLife_]

I think they were talking about exploiting the fact stuff expands when its hot.. and when it cools it shrinks... just what you just proved ;)

Exactly but whats keeping the bearing from expanding along with the rest of it?

[IYP]

hopefuly heel be able to time it right....the outer stuff will expand before the inner stuff.

[dippyskoodlez]

Exactly but whats keeping the bearing from expanding along with the rest of it?

-or- if you heat it up a ton, and expand them both, and then cool it, it'll move it enough to get it going.

heat it up to where it gets shoved together, and when it shrinks, maybe it'll have enough room to budge loose?

[Unknown_road]

A volt is the electromotive force (pressure) needed to move one ampere thru a one ohm resistance.

MOVE, is the relivant word here, if you have volts you have current..... you need a new professor.

Well lucky for you we use american books so you can read it yourself :D If you want to know more about electricity read "Introductory Circuits for Electrical and Computer Engineering" by Nilsson and Riedel.

[Comp-Freak]

Turning the compressor upside down doesn't work? I can immagine the oil slowly streaming thru the compressor and makes it run smooth.

Btw, indeed, Unknown_road is right.

[wdrzal]

you guys think volts can be seperated from current, if you have one you have the other. they are 2 different measurements of the same thing, electricity.voltage is part of the current, if you have a sensitive enough meter at any 2 points you pick the voltage will change due to line lose from resistance. you may read voltge ACROSS 2 points with a meter but it travels with the current(getting weaker from resistance as it goes)


If you have 1 foot of wire ,no current, then you apply current to one end, you can read the voltage at the other end, how did it get there? it travled thru the wire with the current..... voltage is part of current , most books explain them in different paragraphs but they can't be seperated. they do teach you read voltage across 2 points but that dosn't mean it doesnt move with the current.

[_HL4E_HalfLife_]

Turning the compressor upside down doesn't work? I can immagine the oil slowly streaming thru the compressor and makes it run smooth.

Btw, indeed, Unknown_road is right.

I havn't tried that yet because its still in the A/C and i don't wanna brake my back :nono:

[wdrzal]

you guys think volts can be seperated from current, if you have one you have the other. they are 2 different measurements of the same thing, electricity.voltage is part of the current, if you have a sensitive enough meter at any 2 points you pick the voltage will change due to line lose from resistance. you may read voltge ACROSS 2 points with a meter but it travels with the current(getting weaker from resistance as it goes)


If you have 1 foot of wire ,no current, then you apply current to one end, you can read the voltage at the other end, how did it get there? it travled thru the wire with the current..... voltage is part of current , most books explain them in different paragraphs but they can't be seperated. they do teach you read voltage across 2 points but that dosn't mean it doesnt move with the current.

[shinymod]

you guys think volts can be seperated from current, if you have one you have the other. they are 2 different measurements of the same thing, electricity.voltage is part of the current, if you have a sensitive enough meter at any 2 points you pick the voltage will change due to line lose from resistance. you may read voltge ACROSS 2 points with a meter but it travels with the current(getting weaker from resistance as it goes)


If you have 1 foot of wire ,no current, then you apply current to one end, you can read the voltage at the other end, how did it get there? it travled thru the wire with the current..... voltage is part of current , most books explain them in different paragraphs but they can't be seperated. they do teach you read voltage across 2 points but that dosn't mean it doesnt move with the current.

we know they cant be seperated, thats simple. that doesn't stop the fact that voltage is defined as potential difference between two points. yes if there is a current then there must be voltage and vice versa, but in the standard model voltage is a measurement of the difference in potential between two points and therefore is seen as stationary.
if you look at it in terms of the "mr coulomb" model, then each charged particle carries a charge equivalent to the voltage, and moves through the circuit. HOWEVER, this doesn't change the definition of voltage, which infers that a potential difference does not flow...

you in fact proved yourself wrong when you said:

A volt is the electromotive force (pressure) needed to move one ampere thru a one ohm resistance.

the potential difference between the points causes the current to move through the resistance.

and you cant say that the voltage "got from one end of the wire to the other with the current" that's completely incorrect.
what actually happens is that you apply a voltage to one end of the wire, and the other end for instance is grounded. what this means is that there is a difference in potential between the two points (the voltage at one end, and nothing at the other) this causes a current to flow through the wire. also you can't "apply a current". you apply a voltage, which CAUSES the current.

[Comp-Freak]

voltage is part of the current, if you have a sensitive enough meter at any 2 points you pick the voltage will change due to line lose from resistance. you may read voltge ACROSS 2 points with a meter but it travels with the current(getting weaker from resistance as it goes)And that's the reason why the resistance of a voltmeter is as high as possible, so he change the current as less as possible. (hehe, is that good english? ;))

[wdrzal]

we know they cant be seperated, thats simple.

go back to my original statement where I said "you should have 30 volts going thru the run windings" so you do agree that volts and current can't be seperated and I stand by my original statement as correct. voltage is measurd between 2 points, any where on the run winding you will have appox. 30 volts.

[shinymod]

i agree that there will be 30 volts dropped across the run windings, but... strictly speaking you should say across. as the voltage isn't "going thru" them... it's being pretty anal i know... but it's still the current going through, with the voltage across. :p:

also everywhere on the windings will not read 30V... if you measure from one end of the winding to the other, it will read 30V. however if you measure from one end of the the winding to halfway along the winding's wire it will read 15V, as the 30V is dropped proportionately along the length of wire.

[_HL4E_HalfLife_]

I got the compressor today :woot: :woot: :woot: I also tried 240v on it and for a split second and it did seem to go faster but when i put 117v to it it still ran really slow. I also poured some oil in the discharge and the suction lines but no change. I kinda ran out of time because the shop was closing up for the day so ill try some more things tonight. Hers 2 pics of the stuck compressor not that it matters really lol.

Ps. Ill also ohm out the winding to make sure there not the problem.

[Unknown_road]

you guys think volts can be seperated from current, if you have one you have the other. they are 2 different measurements of the same thing, electricity.voltage is part of the current, if you have a sensitive enough meter at any 2 points you pick the voltage will change due to line lose from resistance. you may read voltge ACROSS 2 points with a meter but it travels with the current(getting weaker from resistance as it goes)


If you have 1 foot of wire ,no current, then you apply current to one end, you can read the voltage at the other end, how did it get there? it travled thru the wire with the current..... voltage is part of current , most books explain them in different paragraphs but they can't be seperated. they do teach you read voltage across 2 points but that dosn't mean it doesnt move with the current.

volts and current can be seperated theoretical. infinite resitance and you don't have current but you can have voltage. A superconductor(no resistance) can have current without having any voltage drop. But across(for voltage) is just the official statement that you should use. At the university I was going too they kept pounding it in my head for a year :stick:

current is a result of voltage, the voltage doesn't travel along. Think of it as a phase-change system, you have a high pressure and a low pressure (the voltage) the cap tube (the resistor) and you have the gas itself (the electrons) the gas will flow from high to low pressure(current). The pressure itself doesn't move though. But it's all about definitions don't care about it too much.

[_HL4E_HalfLife_]

Well it turns out the compressor isn't tight in fact it turns really easy the problem is electrical :mad: :mad:. What gets me is this A/C the compressor came out of is brand new never used so how did the wiring get damaged if the only time this A/C was ever run was at the factory where it was built.

I've cut the compressor open to learn more about why this compressor failed.

BTW the ohm readings were .010,.009,.005 u can tell from that ,that something isn't right in the windings.

[_HL4E_HalfLife_]

On further investigation for some reason the start winding burned up in 1 small place. If anyone is interested ill post a pic of what it looks like im sure some of you havn't seen the insides of a burned up compressor.

[total_assault]

srry posted something outdated didnt see that there are three pages to this thread thought there was only one...

[_HL4E_HalfLife_]

srry posted something outdated didnt see that there are three pages to this thread thought there was only one...

Hehe np, Does anyone think this would be good info to turn into a sticky thread? I'm sure im not the only one thats had a stuck compressor.

[berkut]

Please post pics :D

[_HL4E_HalfLife_]

You can see why this compressor was never gonna get up to speed again :( this would have been a great workhorse.

[piotres]

I have also a LG rotary which doesn't want to start :mad: ...


http://www.xtremesystems.org/forums/showthread.php?t=57053&highlight=piotres

I have wrote of that in this topic ...

Any help for me ?? :confused:

Best Regards
Peter

[_HL4E_HalfLife_]

I have also a LG rotary which doesn't want to start :mad: ...


http://www.xtremesystems.org/forums/showthread.php?t=57053&highlight=piotres

I have wrote of that in this topic ...

Any help for me ?? :confused:

Best Regards
Peter

Have u read all through this thread and tried any of the following?

[wdrzal]

Hehe np, Does anyone think this would be good info to turn into a sticky thread? I'm sure im not the only one thats had a stuck compressor.


No this should NOT be a sticky for sure. You said at the very begining that you had a stuck compressor, all responses where based on that. In Truth you mis-diangnosed a burt winding. This shouldn't have been missed ,simpley metering the windings would have reveiled that problem.

When a compressor dosen't run the first thing you due is check voltage and the external start componates, like capacitor, relay, overload. If all that checks out you meter the windings for breaks ,shorts, and leakage.Only if all that checks out can you say the problem is mechanical.

Always check the electrics FIRST.

[_HL4E_HalfLife_]

No this should NOT be a sticky for sure. You said at the very begining that you had a stuck compressor, all responses where based on that. In Truth you mis-diangnosed a burt winding. This shouldn't have been missed ,simpley metering the windings would have reveiled that problem.

When a compressor dosen't run the first thing you due is check voltage and the external start componates, like capacitor, relay, overload. If all that checks out you meter the windings for breaks ,shorts, and leakage.Only if all that checks out can you say the problem is mechanical.

Always check the electrics FIRST.

ur always so negitive u know that. Theres alot of useful information in this thread prehaps it should be redone in 1 single post and than made into a sticky. Piotres has made a post about a stuck compressor as well and some of the info on here may be useful to him.

[wdrzal]

previously in another thread you stated you were a electric motor expert. its not being negative,just truthful.Besides everyone of us learns from mistakes we make, nothing negative about that.You didn't even have a stuck compressor. this thread is a poor example how to diagnose a compressor. I just outlined the list to check above.I don't want everyone who has a compressor that doesn't run to think its stuck. In fact mechanical failure of hermetics,was not that common, except for the flood of low quality ones that are now showing up everywhere.

I think its much more important to point out mistakes rather then to say nothing and let the next reader follow a incorect procedure.

I don't give out too many "that-a-boys" because I guess I expect perfection , correcting mistakes and striving to do the best job possible is not "negative."

my company motto is "Perfect or better" I say if you can't do a job better than perfect,I'll accept perfect.


I do agree a lot discussion is needed on the electrics.

If fact now come to think of it I never seen any flow charts posted,or troubleshooting lists posted, that would be a good place to start.

[total_assault]

Well, Wdrzal you seem experienced and insightful, could you make a troubleshooting list and/or flowchart so we can consult that before asking questions?

[_HL4E_HalfLife_]

I don't give out too many "that-a-boys" because I guess I expect perfection , correcting mistakes and striving to do the best job possible is not "negative."

my company motto is "Perfect or better" I say if you can't do a job better than perfect,I'll accept perfect.


I do agree a lot discussion is needed on the electrics.

If fact now come to think of it I never seen any flow charts posted,or troubleshooting lists posted, that would be a good place to start.

If u expect perfection that ur expecting too much! noone is perfect! not even u.

[wdrzal]

I said I strive for perfection, not that I am, far from it, I just try to point out mistakes so they don't get repeated.I always said the best lessons are learned from the worst mistakes.

A guide was started but some health problems I having put it on a tempory hold . I can find some troublshooting and flow charts in the mean time.



I have a problem with meeting the 200KB limit all the time, every thing I try to post the file is to large, What is the best way to resize the files?

by all mens ask questions!!!! thats the only way to get answers.Very few questions go unanswered .