could a non operating evap fan cause enough liquid flood back to seize a comp

[karara_Fridgie]

absalute nitemare trying to help family friend with his mobile coolroom. its a van and its got an extra compressor mounted to the motor, same as an ac motor. we just replaced the comp as the old one seized. its actually a freezer room, after canging the compresor i evacuated and charged the system so it was running at about 20 pound. it runs on 404a.

its been about 2 weeks and im pretty sure the comp has gone again. only this time when i had a look at it, the evap fans have stopped working for some reason,

my question is, if the evap fans were to stop would that cause enough liquid flood back to damage the comp?

have i overcharged the system?

[karara_Fridgie]

do new automotive ac comps come pre-charged with oil?

[sedgy]

hi it sounds like too much gas < did you weigh it in?< but isent there a L-P swich on the system? sedgy . and what is the extra compressor fitted to system?

[karara_Fridgie]

there is an lp switch, it seemed to be running good at 20 lb , its a 134a comp fitted out with new seals and stuff so its heavier duty,
i was thinking that because the evap fans arent running that would simulate an overcharged system causing liquid to merge back to the comp.. u know what i mean

[sedgy]

hi , an L-P switch will stop a small display counter is a shop or a 250ton industral water cooler in a factory. so we have got to the bottom of the problem = you dont know the size of the compressor well ITS TOO BIG< and you may have overcharged it ? making the evap to freeze up then the fans catch onto the ice and stop running.
in your last thread you ask < again< was it cos you over charged it? the comp went down,? well I ask again , did you weigh the gas in? sedgy,

[Gary]

Start here:

http://www.refrigeration-engineer.com/forums/showthread.php?t=19701

[karara_Fridgie]

hi , an L-P switch will stop a small display counter is a shop or a 250ton industral water cooler in a factory. so we have got to the bottom of the problem = you dont know the size of the compressor well ITS TOO BIG< and you may have overcharged it ? making the evap to freeze up then the fans catch onto the ice and stop running.
in your last thread you ask < again< was it cos you over charged it? the comp went down,? well I ask again , did you weigh the gas in? sedgy,


hi , an L-P switch will stop a small display counter is a shop or a 250ton industral water cooler in a factory. so we have got to the bottom of the problem = you dont know the size of the compressor well ITS TOO BIG< and you may have overcharged it ? making the evap to freeze up then the fans catch onto the ice and stop running.
in your last thread you ask < again< was it cos you over charged it? the comp went down,? well I ask again , did you weigh the gas in? sedgy,

the compressor that was on it had some numbers missing on the sticker so the auto fridgie i sent it to said he "figured out" which comp it was and ordered in a replacement, the orginal comp had been on there for a few years i would assume. i charged it to about 1.5kg, any less than that and it was pumping down. oh and by the way, i am well aware wat an LP switch is, and no, that is not the bottom of the problem

mmm... how could u possibly tell its to big dude???? the evap never froze up... the fans just dont work man. i wieghed the gas, but i had no way of knowing the proper measurement, i got it to run at 20lb. but can u answer my question....

if the fans stopped would that cause enough liquid to go back to compressor to damage it:o

[karara_Fridgie]

basically i wanna know if its my fault that this new compressor is fcuked, or if its because these fans stopped workin, cause its gunna cost me if it was my fault

[charlie patt]

how many fans on evap and is a tm15 comp b whatbis the make of systemeen fitted

[SteveCass]

yes, if the fans stop that can mean liquid fails to completely boil off and flood back to the comp.

There may be other problems, but getting the fans running ought to at least do away with that issue and allow you to move on.

Just make sure that the system isnt in defrost, that can stop the fans on some systems. I have never worked on mobile gear, but can only assume they work on the same principle as fixed installs and defrost every 4hrs or so?

Steve

[karara_Fridgie]

yes, if the fans stop that can mean liquid fails to completely boil off and flood back to the comp.

There may be other problems, but getting the fans running ought to at least do away with that issue and allow you to move on.

Just make sure that the system isnt in defrost, that can stop the fans on some systems. I have never worked on mobile gear, but can only assume they work on the same principle as fixed installs and defrost every 4hrs or so?

Steve
yer good point mate, i never worked on it before either, now i wish i never touched it. umm though when i was there the dixel was still showing it was calling for cooling, wether or not those fans are on a seperate timer im not sure. though i would assume that the comp would cut out when its on defrost, so yer good point ill have to check that out.. i tried tracing the wiring through this damn van,, ughh,, it was torture had no luck

[karara_Fridgie]

[/QUOTE]


how many fans on evap and is a tm15 comp b whatbis the make of systemeen fitted

mate i dunno.. its got 2 fans on the indoor. i think the system has jus been put together using different branded parts,

[charlie patt]

need to know what sysyem is on there as not many use dixell usually lae and theytend to df every hour and tend to be hot gas df

[monkey spanners]

Could faulty evap fans lead to flood back to the compressor and subsequent failure? yes.
Did they in your system? i don't know and neither do you it seems.

Read through Gary's link, it will help you understand how the individual parts work as a whole, having such an understanding will help in diagnosing problems and in knowing what to check when repairs need to and have been made.



Start here:

http://www.refrigeration-engineer.com/forums/showthread.php?t=19701

[karara_Fridgie]

charlie,, hg df would make sense,

and to Monkey Spanners, me not silly.. i just dont trust my judgement on something i havent worked on before, sure the basics still apply but i never charged a system like that before. one would assume you get it to run at a certain pressure without it pulling itself down on pressure., being a freezer i figued 20 lb on 404a would suffice. all i did was gas this puppy, another fridgie fitted the new comp. i know that a faulty evap fan would obviously not boil off the liquid but i jus had to be reassured that it could cause something xtreme like a seized comp. i know on a normal recip comp, you get the banging noise and you might smash a few reeds i jus was not sure if this would cause a seize up on a car type comp.

[karara_Fridgie]

charlie,, hg df would make sense,

and to Monkey Spanners, me not silly.. i just dont trust my judgement on something i havent worked on before, sure the basics still apply but i never charged a system like that before. one would assume you get it to run at a certain pressure without it pulling itself down on pressure., being a freezer i figued 20 lb on 404a would suffice. all i did was gas this puppy, another fridgie fitted the new comp. i know that a faulty evap fan would obviously not boil off the liquid but i jus had to be reassured that it could cause something xtreme like a seized comp. i know on a normal recip comp, you get the banging noise and you might smash a few reeds i jus was not sure if this would cause a seize up on a car type comp.[/QUOTE]

[charlie patt]

you had better check what comp its on and what suplier supplied it, if its a sanden tm they useually only come dry or with a very base level of oil and it can be of varied type depending on suplier if its a sanden a evap fan out in my experience will make little difference unless used for a long time like it i have sandens like a ball of ice on many occasions they take a lot of stick however they like there oil and they dont like short cycling

[monkey spanners]

Karara, i'm pleased you aren't silly. It is nice to get a second opinion on things, i'll often phone a friend for advice on stuff i have not worked on much before.

You might get a better response by posting your question in the transport section seeing as its a fridge van.

Jon :)

[mikeref]

do new automotive ac comps come pre-charged with oil?
Compressors for vehicle air-conditioning are precharged unless tag says otherwise. Did you check oil content of failed compressor? New compressor may have been charged with different brand of oil and now 2 types of oil in system. You say its a freezer room, what is its dimensions? 9kg's is a lot of refrigerant for small auto compressor to deal with.. Mike.

[Gingerair]

You need to check the setup of the Dixell controller.
Has it got 2 temperature sensors attached ??
If i'm reading you post correctly, none of the fans are running, so you've got to ask yourself what's the chances that they've all failed at the same time ???
Check the evap fan supply & control..
If the evap coil is not cold enough the controller may stop the fans from running.
Have you asked your 'auto fridge' what type of oil & oil charge the replacement compressor was supplied with ??
Good Luck !!

[karara_Fridgie]

thanks for the help people.. i will let you know how it all pans out

[karara_Fridgie]

ok i spoke to my supplier he said they come with oil and it sounds like i overcharged it, damn it... $600 for a new comp... do u guys knows if the compressor can be rebuilt at a cheaper price? last time it was a bent piston rod and im sure i could have changed it out

[mikeref]

ok i spoke to my supplier he said they come with oil and it sounds like i overcharged it, damn it... $600 for a new comp... do u guys knows if the compressor can be rebuilt at a cheaper price? last time it was a bent piston rod and im sure i could have changed it out
I would be careful about fitting another compressor untill all bases are covered. So many types of auto compressors out there. Need to know origional comp make and its speed. There are variable capacity compressors and you do not want to overcharge with oil, 40cc over and it will fail. Mike.

[Tayters]

When you charged the system was the interior space to temperature? It may appear correctly charged when initially started but as space temp falls then less refrigerant will be required so you could end up in an overcharged state.

Weather this overcharged condition existed or not though, with no evaporator fans running certainly wouldn't help prolong compressor life. Do the fans work from a coil temperature sensor?

Car compressors I've seen have pressure relief valve on them (at least the one I saw that a mechanic overcharged by twice the amount had :p)
How to prove it wasn't your fault? I suppose you need to get it running again and see if there is any floodback with the same charge back in. If it was just off the point of pumping down with your charge then I would doubt it was overcharged unless interior space temp was very high at the time.

Good luck,

Andy.

[Mark II]

Karara,

Don't take this the wrong way.. Your compressor has failed for the exact same reason as the original you replaced.. Most likely you will be another $600.00 poorer in 2 weeks time.. It is very difficult to overcharge this type of system as discharge pressures are typically very high.. Please check your hot gas defrost control set up.. Make sure the liquid solenoid actually closes when the Hot gas energises, & find out what defrost termination is used.(Pressure or temp.) If hot gas is left on too long & discharge pressure drop too far the system will flood back. There may also be defrost termination stat on the evap return bends overriding your Dixell & preventing the fans running at all.. Make sure all fans are spinning the same direction.. that someone hasn't put 1 blade on backwards.. If you fit another comp, don't let it out of your sight until you've found something wrong..

[karara_Fridgie]

When you charged the system was the interior space to temperature? It may appear correctly charged when initially started but as space temp falls then less refrigerant will be required so you could end up in an overcharged state.

Weather this overcharged condition existed or not though, with no evaporator fans running certainly wouldn't help prolong compressor life. Do the fans work from a coil temperature sensor?

Car compressors I've seen have pressure relief valve on them (at least the one I saw that a mechanic overcharged by twice the amount had :p)
How to prove it wasn't your fault? I suppose you need to get it running again and see if there is any floodback with the same charge back in. If it was just off the point of pumping down with your charge then I would doubt it was overcharged unless interior space temp was very high at the time.

Good luck,

Andy.


Karara,

Don't take this the wrong way.. Your compressor has failed for the exact same reason as the original you replaced.. Most likely you will be another $600.00 poorer in 2 weeks time.. It is very difficult to overcharge this type of system as discharge pressures are typically very high.. Please check your hot gas defrost control set up.. Make sure the liquid solenoid actually closes when the Hot gas energises, & find out what defrost termination is used.(Pressure or temp.) If hot gas is left on too long & discharge pressure drop too far the system will flood back. There may also be defrost termination stat on the evap return bends overriding your Dixell & preventing the fans running at all.. Make sure all fans are spinning the same direction.. that someone hasn't put 1 blade on backwards.. If you fit another comp, don't let it out of your sight until you've found something wrong..

thanks for those tips guys, im gettin the van at my house 2moro, its not fixed yet, but i can still check if the hg defrost solenoid is working, and i also need to figure out why those fans werent working, it may have been on defrost but ill double check.