[JCR6910]

Hello Everyone!

I'm working on a Global Refrigeration 3-Door reach-in freezer with glass doors.
Model is ULG80BCP-6
Compressor is a KATB-015E-CAV-234 (404A).
Original Run Capacitor was 130-156 330VAC (copeland).
Replaced with a BMI MARS 124-156 330VAC (local part).

A few weeks ago I got a call for this unit (customer says "not working - making lots of noise). I found the run capacitor blew the top off of it. The whole unit would shake violently trying to run. I also found the service valves leaking, unit low on charge, and has bad discharge valve plate (high side leaks back). Replaced run capacitor with local supply part and replaced valve plate assembly and service valves, evacuated unit below 500 microns (around 250-300 microns believe) and weighed in new refrigerant R404A to factory specs. Unit was working great. Got a call back and I came back today to hear compressor short cycling off compressor safety. Unit pulls about 15-16 amps constant until trips off. Start capacitor tested fine at 25uF. Run capacitor was extremely hot and did not read anything at first, started to cool down and measure 260uF (rated 124-156uF). I confirmed the capacitors ratings are correct from Emerson website so doesn't look like someone before me installed wrong capacitor (hopefully I didn't!). Unit still has refrigerant, compressor pulls a vacuum when suction service valve is front seated, no leak back from discharge side. When unit runs (5 seconds), discharge pressure doesn't get above 215psig. I know I need to replace run capacitor again but i'm not sure what else is going on with this unit. Any help would be greatly appreciated! This manufacturer is horrible, still waiting on tech support to call me back on another repair for 3 weeks.

JC

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[JCR6910]

Quick update: I measured 45 amps at a different compressor terminal.

JC

 

[Snapperhead]

you have your technical terms reversed .... thats a Start cap thats busted

Sounds like the start relay is bad

Make sure the power is correct .... like if its a 120v unit , its got 120 while running

Low voltage is bad

That new cap is probly toasted as well

 

[JCR6910]

Yup, I'm backwards today. I just took a closer look at start relay, sound like a little chattering going on inside. Thanks for getting me back on track!

JC

 

[Dchappa21]

When you find a blown up start cap make it a habit of just replacing all starting components....

Most of the time the relay causes the start cap to blow.

 

[t527ed]

When you find a blown up start cap make it a habit of just replacing all starting components....

Most of the time the relay causes the start cap to blow.

:ditto: always.

on the little tin cans if relay or cap is bad they always get relay, cap and overload.
all parts replaced the first time is better than a call back.

 

[JCR6910]

I agree. I do normally replace all start components on tin cans when one component fails. This is a semi-hermetic compressor and the relay is pretty pricey, almost $100 online. Parts house is closed so not sure our cost yet. It's a 040-0166-20 potential relay. I'm honestly a little on the fence about replacing a part over $100 just to be safe or in an effort to avoid a call back. (In this case, it appears to be the cause of my failed start capacitor.) What do you guys think?

 

[johnqpublic]

replace the relay. nuff said.

 

[steve36558]

I agree with John, start relay hangs up too long will blow a start cap.

 

[VTP99]

Ohm out the compressor. If the start winding is week you will here that relay chatter. Also open the relay up and check the contacts. :det:

 

[steve36558]

On the face of the relay you will see a black silcone spot, under that is the scew that holds the case together for the start relay. Check the contacts, they might be pitted and some sand cloth would clean them up and will buy you some time!

 

[IRBH]

Ohm out the compressor. If the start winding is week ................:

HUH?

 

[IRBH]

So, you fix your own freezer, do you.
The length people go on here masquerading as techs!

A tech would know the nomenclature of the parts and would not think twice about replacing the potential relay which clearly caused the trouble. (twice)

 

[VTP99]

HUH?

Do you no how the potential relay works ?

 

[IRBH]

Do you no how the potential relay works ?

Actually, dying to hear how start winding gets "week".

Open, intermittant, shorted, grnded.
But weak? I don't think that I have that scale on my vom.

 

[VTP99]

Actually, dying to hear how start winding gets "week".

Open, intermittant, shorted, grnded.
But weak? I don't think that I have that scale on my vom.

HaHa Must have been my spelling that confused you. Weak as in high resistance. You do know how the relay works correct ?

 

[IRBH]

HaHa Must have been my spelling that confused you. Weak as in high resistance. You do know how the relay works correct ?

Now I'm wondering how the start winding gets "hi resistance" (I've had a hard day). Open (infinite) resistance, heat winding so ptc shows up?

 

[KB Cool]

So, you fix your own freezer, do you.
The length people go on here masquerading as techs!

A tech would know the nomenclature of the parts and would not think twice about replacing the potential relay which clearly caused the trouble. (twice)

I agree! He's a fake!:grin2:

 

[VTP99]

Now I'm wondering how the start winding gets "hi resistance" (I've had a hard day). Open (infinite) resistance, heat winding so ptc shows up?

The start winding has higher resistance then the run. With the potential relay, not a positive temperature coefficient resistor (PTCR) the relay coil is energized by the potential of the start winding. It's my thinking that if the winding has to high of a resistance, it cannot provide the current, to bring the motor up to speed. This would cause the relay to drop out. Not drop out like a current relay but close the contacts and bring the start cap back into play. If I'm wrong I'm sure some one will chime in and correct me.

 

[VTP99]

I agree! He's a fake!:grin2:

Well he talked a pretty good game on till the reverse capacitor part :eek2:
but how would it run at all ? :toetap: