Reply7.5 pounds sounds low on a 5 ton split system.
Regular Guest
5 ton scroll compressor in a split system.
Suction ~40psig
Discharge ~210psig
Amps 30+A
Superheat ~17
It is a 3 phase compressor, pulls 30 amps from the get go and will go all the way to 40 amps (and shut off)
The winding(s) resistance is about .5 ohms on all of them. It also doesnt sound great when it is running. I recovered 20 pounds of refrigerant from this system, recharged with around 7.5 pounds... After cleaning the ridiculously dirty evaporator.
Just looking for affirmation, thank you for your input.
God Speed, Jim. We'll miss you - 2-26-23
7.5 pounds sounds low on a 5 ton split system.
Professional Member
Did you measure amps on all 3 legs?Originally Posted by wdshea
Regular Guest
I'm guessing R-22. If so looks like low suction, normal head. more info would help. I like to megaohm the compressor to ensure the windings are good.
Professional Member*
split unit what was the ambient around the condenser 210PSI air cooled is low for R-22.how is the condenser on being clean...flush it inside out.... is this a commercial site strip mall or residence?
"when in doubt...jump it out" http://www.youtube.com/watch?v=U1qEZHhJubY
Regular Guest
Im sorry, i was thinking of my suction saturation when i said 40, pressure was around 69psig on the suction. Yes i checked all three legs. I cleaned the condenser twice. This is commercial.
Megaohm the windings to ground?
Professional Member*
You can use a megger if you have one. Isolate the leads from the compressor and megg from the compressor terminals to ground.
Professional Member
typically, a short to ground is not going to cause high running amperage.
That would be more likely to cause high instantaneous amperage and result in a breaker trip.
I would leave the megger in the truck here.
I'd look for a performance curve on that pump and see what the manufacturer says that it SHOULD draw under those conditions.
I suspect that you'll be replacing a compressor, soon, though.
Regular Guest
The olp trips pretty quick, it never pulls less than 30 amps, so it only runs about 5 minutes, if that. I thought that maybe a previous tech may have the motor running backwards, so i switched some leads. AmP draw went to 12A but the compressor sounded like hell, so i'm certain it was running the right way.
Professional Member
A grounded winding will typically pop the breaker/overload instantly, not over a couple of minutes.
Regular Guest
What else could this be? I was thinking shorted windings
Professional Member *
What is the LRA and what is the compressor rated at? 30 plus amps sounds high in a 5 ton system.
I rather do nothing and be happy than to do something and not be happy
Professional Member*
My guess would be the bearing are going bye bye. 30 amps on a 5 ton 3 phase compressor? Not long for this world!
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Regular Guest
RLA 20A
LRA 120A
Professional Member*
Thats what happens when you run twice the correct charge with a dirty evap!
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Professional Member *
If its pulling high amps then condemn the compressor
I rather do nothing and be happy than to do something and not be happy
Professional Member *
Its a matter of time before it fails
I rather do nothing and be happy than to do something and not be happy
Regular Guest
Check your volts when running? Bad contacor breaker disconnect? Tighten all connections check voltage drops across them and temps..
Professional Member
What he said. I had one start at normal amps then climb as it ran until it tripped. Boss thought I was crazy changing compressor but had no other ideas, then was happy when it fixed the issue.
Regular Guest
It could be oil return. If you dont draw the oil back your amps will rise as it runs. It may start normal then rise up. I would be thinking that route.
I have heard some will mix in some POE to help draw mineral back?
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