Inverter Box whirlpool fridge Wrx988sibm

[Roosevelt Stewart]

I am working on a whirlpool fridge. Compressor not running and the tech sheet is missing. I replace the inverter box but compressor still not running. I and getting 123 volts AC input and 3.3 volts DC to the inverter. I think I need 4-6 volts which leads me to believe that the Main control board may be bad. Inverter is not attempting to start the compressor. Compressor reads 6.4 volts across all leads. Baffled 

[16345Ed]

54 minutes ago, Roosevelt Stewart said:

Compressor reads 6.4 volts across all leads. Baffled 

Did you mean ohms?

[Roosevelt Stewart]

Sorry, yes ohms

[16345Ed]

Spec on inverter:

3-6 VDC

[16345Ed]

You really need tech sheet so you can enter diagnostics to do some testing. 

Edited January 31, 2018 by 16345Ed

[Roosevelt Stewart]

Thank you. Then if converter is good, it should attempt to start compressor?

[Roosevelt Stewart]

I agree. Can’t find it anywhere 

[16345Ed]

1 minute ago, Roosevelt Stewart said:

I agree. Can’t find it anywhere 

Are you a professional tech?

[Roosevelt Stewart]

Yes

[darren412]

Is a 3.3 dc  volt reading coming from the main control to the inverter good enough to have the inverter run the compressor 16345ed ?   I see that you had found the spec range of 3 to 6 volts DC for the inverter. That reading of 3.3 seems to be on the low end but within the specs ??

[16345Ed]

Right and you’d think it would be near 6VDC when so far below temp. 

Roosevelt, you should consider subscribing to this site. Well worth it, I found the tech sheet in less than a minute. Because I have a membership. 

[16345Ed]

I would also test evaporator thermistor(s)

[Roosevelt Stewart]

I just subscribed. The condenser fan is running by the way

[16345Ed]

20 minutes ago, Roosevelt Stewart said:

I just subscribed. The condenser fan is running by the way

????

 

welcome aboard!

Edited January 31, 2018 by 16345Ed

[AccApp]

17 minutes ago, Roosevelt Stewart said:

I just subscribed. 

Pro is the only way to go, bro! Welcome to the team

Edited January 31, 2018 by AccApp

[AccApp]

17 minutes ago, Roosevelt Stewart said:

The condenser fan is running by the way

Better go catch it, you'll need it if the compressor starts running as well.

[Rhubarb Tau]

Agreed, start with the tech sheet (SvcTest 5, maybe), but FWIW it's tricky to check the inverter output. Have to assume the inverter's good since you've replaced it, but if you run into this again, couple things to keep in mind:

• The signal that the inverter is looking for is just frequency. The duty cycle or effective (filtered) DC voltage isn't specified, and may not vary with demand in a way that we'd expect. Frequency at min. speed is ~54 Hz. , at max ~ 150Hz.
• Even when the inverter is getting a demand for compressor runtime, it'll check to see if the compressor is seized or hard to start, and disable compressor output if the compressor isn't turning over as it expects. In practice, I've found that the inverter will pulse its output on for ~ 1/2 second , and if id doesn't like the current draw it sees , it'll wait (maybe 10-20 sec.) and try again. If you're not watching your meter really close (or using a min/max trigger, etc.) , or if your meter has a slow update rate, you may miss the output pulse from a good inverter trying to start a seized compressor.

Come to think of it, it'd be nice if somebody would come out with a 3-phase inverter-based hard start kit. To the best of my knowledge, it wouldn't violate the laws of physics.

[Samurai Appliance Repair Man]

2 hours ago, Roosevelt Stewart said:

I just subscribed.

I think you meant that you subscribed as a free Grasshopper member. If you’d like to subscribe as a professsional tech member, this page has more information: https://appliantology.org/store/product/11-professional-appliantologist/

 

[darren412]

The fox that bit you died

[Roosevelt Stewart]

On ‎1‎/‎30‎/‎2018 at 10:00 PM, Samurai Appliance Repair Man said:

I think you meant that you subscribed as a free Grasshopper member. If you’d like to subscribe as a professsional tech member, this page has more information: https://appliantology.org/store/product/11-professional-appliantologist/

Update, turned out to be the compressor. I was able to obtain a tech sheet from the local parts supplier. Thanks for all your help

 

 

[Roosevelt Stewart]

 

The compressor turned out to be faulty. This type unit is going to be to hard diagnosis. If you can't trust your meter....

[16345Ed]

How did you determine it was the compressor?

[Roosevelt Stewart]

Changed the inverter under warranty, checked thermistor, Control boards, all voltages were in range of tech sheet. By the process of elimination, I took a very expensive chance