Prestcold Compressor

[colingwatkins]

The compressor will run when turned on manually but will not restart after shutting down. Is there a sensor built into the motor that could be faulty or a sensor anywhere is else in the system. Hope you can help

[Tony]

colingwatkins,

Have you any more information about the compressor?

[chemi-cool]

All compressors that I know of are equipped with a 3 pole clickson which is located in the compressor's motor windings.

You did not mention the compressors temp.
Was it very hot ?

If it is not hot then the cklixon my be faulty or there is a problem in the control circuit.

[colingwatkins]

The compressor is a Prestcold 12l Part No.57170/7473 Model K202D Voltage 115 volts hz60 FLA 10.7 IBA 48.5 Serial No.KD KID 8410.
The compressor is trying to start making a short buz sound and the volt meter drops 10 volts. If you switch off after it has shut down, wait 3 or 4 hours, switch it on manually it will start. Hope this is of help

[chemi-cool]

In that case, compressor is gone, replace it.

Whatever you will do, it will not be OK again.

[multisync]

In that case, compressor is gone, replace it.

Whatever you will do, it will not be OK again.


Chemi I can't agree with your diagnosis. It appears to me that it is running and going out on it's klixon. then it attempts to re-start and fails.
Letting it cool down and it will run again. This isn't necessarly a failed compressor as I would be looking at condensing problems or low refrigerant before I got as far as you. Even then it's possibly a capacitor or relay faulty.


I wonder what this compressor is on as it's obviously a US spec ? I don't know K202D as a number as they are usually sized as HP but isn't 12L is a low back pressure R12 compressor

Either way we need more information and Colin probably need another engineer to assist

Seek and ye shall find :
http://www.refrigeration-engineer.com/forums/showthread.php?t=19466

[chemi-cool]

Chemi I can't agree with your diagnosis

Thats The beauty of this forum, we dont have to agree on everything........;) and still be friends....:cool:

I come from the point that everything else in that system is OK.

No other problems were reported.

[multisync]

Thats The beauty of this forum, we dont have to agree on everything........;) and still be friends....:cool:

I come from the point that everything else in that system is OK.

No other problems were reported.



Indeed chemi indeed. :D

You're right to say no other faults were reported but that may be because he may not know there are other faults as yet...

[Frikkie]

Hello Colingwatkins,

Some Klixon type of devices are monitoring the run current is within a preset value and also can be directly monitoring temperature of the actual windings.

Often the temperature of a motors windings is relative to the running current but with refrigeration there are other factors like the temperature of the returning gasses that can affect motor temperature.

If the klixon is tripping it could be current or refridgeration faults or even both. I would first check running currents and accurate running temperatures of the motor. If it is a single phase machine then you might try replacing the capacitors. I would also suggest you check the voltage at the compresser whilst it is running and see it is within 10% of the usual voltage in your area. Low voltage makes chaos with motor temperatures and efficiencies.

The starting problem might be electrical or mechanical. If the oil is full and in good condition and it has low static pressure when restarting then it is probably electrical. Again could be capacitors if single phase machine. If 3 phase then could be a winding part down to earth. This would be seen with a mega test for insulation.

It makes me sad to throw away machines so I would make lots of testing first.

[philfridge]

What is this compressor running ? Is it air or water cooled ? Is compressor being cooled ?

[colingwatkins]

The compressor is running a Fridge and a Freezer and is water cooled. This installation is on a sailing yacht

[D.D.KORANNE]

Motor winding thermistor trip off reasons :
Suction superheat could be too high , voltages could be out of range , short of refrigerant ,filter on suction valve blocked/ partial blockage ,

need to look at reasons causing high winding temperatures

[lowcool]

gday colin
my interpretation is that the compressor trys to start but trips internal overload on windings the first time everytime.you need to measure current draw and compare it to manufacturers locked rotor amps of the compressor,if the measured value is the same as locked rotor amps the compressor is 99.99% stuffed.if the current draw is below locked rotor amps and still trips on internal overload then replace all compressor electricals.if that doesnt work you have just won the .01% and compressor replacement is required.
if your heading my way give us a pm

ps. ithink the IBA number may be the value of your locked rotor amps.you have a reasonably gutsy compressor,how big is your yacht ?

[colingwatkins]

Thanks lowcool, yacht is a 14 x 8 metre catamaran, Kelsall build. Had her for the last 20 years so she is no spring chicken. First time the fridge has ever let me down.

[chemi-cool]

So how did it end?

What did you do to repair the fridge?

I need to know if I'm buying the first pint for multisynk or its going to be his turn.....;)

[multisync]

colingwatkins: The compressor will run when turned on manually but will not restart after shutting down



gday colin
my interpretation is that the compressor trys to start but trips internal overload on windings the first time everytime.?

Got me confuzzed either way...

[multisync]

So how did it end?

What did you do to repair the fridge?

I need to know if I'm buying the first pint for multisynk or its going to be his turn.....;)

deal! :D:D :D

[chemi-cool]

I will be in England at the end of September.

The deal is on!

[multisync]

I will be in England at the end of September.

The deal is on!

Oh wow let's do it!!:cool:

[colingwatkins]

I also think iys the relay, the original was an essexrbm 8327 which lasted 20+ yrs. have been advised to use a Finder 668281100000. had them sent from UK. One has burnt out and the second one is struggling. Cannot find a direct replacement for original, Any chance you can adivise.

[lowcool]

gday colin
i can only suggest contact the manufacturer,or an engineer/technical representative of an wholesaler who dealt or still deals with your brand,their are universal/generic relays etc on the market that maybe suitable for you application.prestcold disappeared from here a long time ago.
be certain the your supply is at the correct voltage
one of your countrymen would have a reasonable idea where to source one,maybe start another thread as this one hasnt gleened to much.
cheers mate

ps-maybe give the girl a 21st present,with an upgrade

[nike123]

I also think iys the relay, the original was an essexrbm 8327 which lasted 20+ yrs. have been advised to use a Finder 668281100000. had them sent from UK. One has burnt out and the second one is struggling. Cannot find a direct replacement for original, Any chance you can adivise.


That Finder relay is rated 30A. Your LRA is probably that IBA of 48,5A which is only 1,5A less then maximum peak current of that relay Which is 50A. I would change it with more suitable for that currents.

Try something like Siemens :
http://cmsapps.sea.siemens.com/controls/speedfax07/07Speedfax_pdfs/07Speedfax_16/16_044-045.pdf

[colingwatkins]

Thanks Nike, the page you sent was for contactors not relays. Is this correct?

[nike123]

Thanks Nike, the page you sent was for contactors not relays. Is this correct?

Yes that is correct, but these are more suitable for your purpose than that finder relays which are not rated for motors which pulls more than 5 times of their nominal current.
Probably old relay was made for that purpose.
How much horse power rating have your compressor motor?
By current, it looks to me as 1,5Hp and 40DP12A* model should do the job.

[colingwatkins]

Thanks again nike, problem is that I cannot find anybody here in Valencia, Spain that can come up with a solution. I have to try and do it myself. I have worked in mechanical Engineering not electrical. Sorry to sound dumb but are you saying I can do away with the relay altogether?

[nike123]

Thanks again nike, problem is that I cannot find anybody here in Valencia, Spain that can come up with a solution. I have to try and do it myself. I have worked in mechanical Engineering not electrical. Sorry to sound dumb but are you saying I can do away with the relay altogether?

You could go with ordinary three phase motor contactor for motors of 2-3HP and still be sure that is fit for purpose rather than some Finder or any other relay not designed to brake-make such motor inrush currents.

[Frikkie]

You could go with ordinary three phase motor contactor for motors of 2-3HP and still be sure that is fit for purpose rather than some Finder or any other relay not designed to brake-make such motor inrush currents.
You should be able to use any relay or contactor with a AC3 rating current the same as your running current. AC3 current marked on a relay is indicating suitable for motor or high inductive loads. :)

[Mick Beeby]

Prestcold units I have connected were the easiest just a contactor supplied by Prestcold,control circuit by unit Klixon Hp/LP&case stat be carefull Klixon self resets,if your unit is on a Starter it could be wired wrong

[sedgy]

hi , there is a fridge compressor workshop in rochdale , lancs who specialise in semi emetic comps the name is trumetic hope you get the problem solved