compressor overload drop out

[FEISTY]

Grab a cold one and get comfortable !! I'm burned out over this one. 6 Door reach-in/walk-in cooler. Rooftop condenser running dual evap coils. 9 YR. old fact. install. Orig, compressor failed due to elect. grounding. Change out with exact replcmt. Ran 2 months to the day. Inspection of sys. proved internal protector trip-out at 11.2 amps. Fact. o/l spec is trip out 19 amps. Voltage 208v. R22 charge with few bubbles in glass. Pressures..242 over 58. Can't get comp. to run more than 2 mins. b/4 11.2 amp. trip. Closes within 3 mins. All start components and both driers new. Coils 100% clean. Dumped...nitro flushed all 3 coils. Measused oil in failed comp. Spec is 43 oz. I drained 38 oz. Only way to keep comp runnng is flash glass to lower charge so RLA is 8.8 to 9.5. Don't care where you are...I will supply refreshments for " life " if you have an answer. Thanks for jumping in !! Also superheat rating with low charge is useless info. Hope to hear from you !! FEISTY.

[andywill]

What make is the compressor and is it semi hermetic or hermetic?
Does it still have the original condenser fan motor fitted?

[Billy Ray]

just a quick reply as i would like 'cold beer' 'on tap' for life..

Is the motor wired correctly i.e star or delta connection? assuming thee-phase motor

Billy Ray

[FEISTY]

Copeland hermetic CR24 compressor and dual condenser motors both working properly. Tached out rpms of both motors and dead on specs. 1ph. system. By the way.. fact. service eng. confirmed bad internal o/l by their opinion. After changeout...there is a BIG BAILOUT of responsibility on their part. Not surprising at all.

[andywill]

New comp has run for 2 months assuming without trouble. Previous comp has run for 9 years before that. Everything is Original or indentical when replaced, If the comp is running above the RLA rated on the comp then I would check that it has always been 208 volts supply cos lower voltage increases amps, verify capacitors are ok (just cos there new doesn't mean they are ok) You have probably triple checked the wiring already, one last thing are you positive that when the compressor was replaced that the discharge line hasn't been partially filled with braize. (just a thought) I have done it myself once and encountered a similar problem with higher than normal amps and tripping internal o/load.
I hope you get to the bottom of it, post reply on your findings.

[FEISTY]

All capatitors were speced and meter tested before install. Voltage is still constant and there is no " stinger " leg. My headache question is how can a factory installed..factory speced overload rated at 19 amp trip is opening at 11.2 amps. Switched Fluke clamp-on meters and manifold gauges to insure test equip. is correct. It is that blasted amp question that doesn't make sense. Also disch. braze made upside down to keep clear. Good imput...thanks.

[philfridge]

Now what coldroom temperature was it when pressures taken ? You seem to be running an R22 fridge at air conditioning pressures that is maybe why the compressor is overloading due to high pressure high amperage. Disconnect the evaporator fan motors and check the T.E.V is shutting down to give fully frosted evaporator coils and let us know suction / head pressure at this point. also carry out pump test on compressor and let us know results.
regards phil

[andywill]

It may be that your compressor o/load is tripping on thermal temp as opposed to current drawn. Most internal protection covers both. Philfridge has a good point especially the pump test as a damaged discharge reed could cause excessive internal temperature of the compressor thus tripping out after 3 mins or so.

[wambat]

I know you said an exact replacement compressor but it sounds like you are running a hi temp compressor and not a low temp compressor and the load is too large for the volume of suction vapor being generated :eek:

[FEISTY]

My appreciation to all of you for your imput . Tomorrow brings a cool morning to review the unit and recheck everything offered here. I will report my success or failure back and hopefully provide information helpful to everyone in the future. Sorry to admit...there is not a lot of tech help available here in Chicago. Tech support lines don't exist as I remember providing when I spent 7 yrs. at the counter. Then there is the " job security " thing that stops sharing info between techs. That's why I SO VALUE the open help everyone on this site offers. Thanks again. Hope your tomorrow is better than my today !! FEISTY.

[Electrocoolman]

Single phase unit. Probably CSR electrics. Try replacing the start relay. Not pulling open and disconnecting start capacitor?
Try measuring volts across relay winding...should be higher than line volts.

[tolits]

Whats the distance of condenser down to the evaps? still original pipe size?

[FEISTY]

Condenser is rooftop unit directly above evap coils. Pipe run is 3 ft. up and 2 ft. to unit. Piping is fact. spec. jnstalled by mfg.

[coolments]

Hi I see you have changed the comp and its fair to assume the system worked well when you changed the comp and has got worse over time.

Did you change all the switch gear when changing the comp, all contactors, new capacitor etc and have you checked all the electrical connections for tightness right back to the power scource, if there is a bad connection this would cause burn on the comp windings over time and lead to this problem. Just something else to check. Regards, Coolments.

[FEISTY]

To all who advised me on this nightmare may I say , again , thank you for the ideas. I am HAPPY to say that the unit is up and running as it should be. After 3 Copeland CK compressors, 9 start components, 3 complete R22 evacuations and fresh refills, 3 liquid and 3 suction driers and all the " uselessly required access valves installed " it finally took installing a Tecumseh body. All pressures fell right in line. Superheat is dead on. Inlet/outlet air temps are as good as they get. Amps are within 2/10ths of specs and are to the low er side. It , in my opinion, goes right back to substandard internal overloads or , possibly, incorrectly speced overloads [ made for smaller compressors ] . All I know is I changed an apple for an apple. I just went to another brand. ALL's well that ends well. Now the corporate battle begins as to if they will autopsy the CK's and truthfully and honestly inspect for the reason of failure. I lost 17 labor hours, 30lbs. of R22, paid for the Tecumseh and start parts, and GAS out of pocket. So far there is no offer for any type or amount of reimbursement. Liabi;ity ends with replacement of body only. I am out everything else. Most important to me is that my customer is finally happy. To wrap this up...thanks again to all and hope this doesn't happen to anyone out there. If it does....think about an early switch...and don't start doubting your skills. I lost a lot of sleep over this and it's not worth it. Feisty

[jure]

Do you have a kriwan protector mounted to control how the compressor is running if you have it try to replace it