Hello and... a problem- fridge wont allow me to charge 134a

[Frigid-Air]

Hello all,

I'm new to the forums and hoping that this problem I'm going to describe is not so new...

I've just done the conversion of an lg linear compressor to a conventional unit.

After I vacuumed the system, I introduced a charge.  Pressure shot up to around 65 psi and stayed there.  Stays there with compressor off and when compressor starts as well.  That's it.  I don't know where to go from here.  Compressor checks out okay on the bench.  Reaches 500 psi with gauges hooked up.  Blockage of sorts in the system?  Where?  Any suggestions?

Thanks for any help anyone may offer.  Happy to be here!

[Terry Carmen]

> I've just done the conversion of an lg linear compressor to a conventional unit.

I don't think you can do that, which probably accounts for at least part of why it isn't working. 8-)

How did you hook it up to the refrigerator wiring?

 

 

Edited December 15, 2020 by Terry Carmen

[Frigid-Air]

The method is tried and true. 

So the problem becomes one of a generic nature.  Do you know of any work-arounds?

[Terry Carmen]

Nope. That thing is a disaster.

Good luck with it.

> The method is tried and true. 

The guy is using the cabinet ground for neutral and has installed a single speed compressor where the software on the board is expecting a variable speed compressor and it isn't even close to being the right size.

 

 

Edited December 15, 2020 by Terry Carmen

[Frigid-Air]

Thanks for looking.  Anybody else?

[Vance R]

Model number of the lg and the compressor. Where are you taking pressures?

[Frigid-Air]

Kenmore Elite 795.73133.410

Replacement compressor is a Panasonic reciprocating.

I get the pressure of 65 psi from the process port after first burst of refrigerant after vacuuming..  Doesn't move after that, compressor pumping or not. That's why I can't continue charging.

Thanks for your interest.

[ECtoFix]

On 12/14/2020 at 3:47 PM, Frigid-Air said:

Reaches 500 psi with gauges hooked up.

I'm confused. 

You're saying you are reading 500 psi system pressure?  If so, then that is DANGEROUSLY high and there's something horribly wrong. 

How much refrigerant did you put into the system? 

[Frigid-Air]

 

Lol.  You probably missed the bench part:

"Compressor checks out okay on the bench.  Reaches 500 psi with gauges hooked up."

Bench tested to test for compressor operation. 

Thanks for replying. 

[Terry Carmen]

4 minutes ago, Frigid-Air said:

"Compressor checks out okay on the bench.  Reaches 500 psi with gauges hooked up."

You may have killed it. Panasonic's small domestic refrigerator compressors aren't rated for that kind of pressure.

In any case, 65PSI on the low side while it's running indicates a huge overcharge or restriction or it's just not pumping anymore.

[Frigid-Air]

The 65 psi reading was prior to checking the compressor for operation. 

Even with the compressor not running, during charging attempt, my expectation was to get more than 65 psi on the first shot and an immediate drop thereafter so I could give it another shot before turning the unit on and tweeking... didn't happen. Just stuck at 65.  

[Vance R]

65 psi is the pressure of r134 at about 65 deg f.  If you have the compressor out, blow throught the condenser and yoder loop to make sure they are clear. Sometimes the linear will burn the oil and the il will clogg the condenser or yoder loop. If the compressor is soldered in place. Remove the scrader valves from the drier and process stub. Start the compressor and there should be suction at the porcess stub and discharge from the drier valve if the condenser and yoder loop are clear. Don't let the highside pressure get above highside design pressure limits. The design pressure should be on model number tag.

[ECtoFix]

4 hours ago, Frigid-Air said:

Lol.  You probably missed the bench part

Well, I've never had a need for nor been in a position to bench-test a brand-spanking new compressor.

I'm still wondering under what conditions you'd read that 500psi.  That's unheard of.  Especially with R134a.

Perhaps you provide a better description of what you're doing.

Anyway.  Were you trying to charge the system by using pressures alone (wrong way), or were you weighing in the refrigerant using scales (the correct way)?

[Frigid-Air]

14 minutes ago, ECtoFix said:

I'm still wondering under what conditions you'd read that 500psi.  That's unheard of.  Especially with R134a.

Try it.  Suction open; high side valve brazed on.  Amazing.

 

16 minutes ago, ECtoFix said:

Were you trying to charge the system by using pressures alone (wrong way)

I'd be very happy to get results any-which way at this point!

[Frigid-Air]

2 hours ago, Vance R said:

65 psi is the pressure of r134 at about 65 deg f.  If you have the compressor out, blow throught the condenser and yoder loop to make sure they are clear. Sometimes the linear will burn the oil and the il will clogg the condenser or yoder loop. If the compressor is soldered in place. Remove the scrader valves from the drier and process stub. Start the compressor and there should be suction at the porcess stub and discharge from the drier valve if the condenser and yoder loop are clear. Don't let the highside pressure get above highside design pressure limits. The design pressure should be on model number tag.

I greatly appreciate your insight and suggestions.  I was going to start breaking the issue down this way but am happy to have some confirmation that it is indeed something that's done.  I'd hate to make matters worse by rupturing something.

2 hours ago, Vance R said:

The design pressure should be on model number tag

Yes.  I've seen these figures.  Hopefully I will be able to get to this tomorrow.