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Those pressures don't sound that wrong to me. That sounds about right for 410A. 38° on your suction and 120 degrees on the high side on a 90-degree day it's about right. If you got a good temperature drop and you're pulling down I don't know why you think you got problems

Originally Posted by David Goodman

I just copied this from another resource.

"When putting the bulb on a vertical line — always — TAIL END UP! And — when clamped to a horizontal suction line — always TAIL END DOWN."

Does this match what you stated?

Correct! Basically, you want to keep the liquid refrigerant in the bulb.

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Originally Posted by BennyD

I bet the pigtail for the TXV bulb is facing up, or it's upside down on the verticle. Numbers don't look horrible.

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I just copied this from another resource.

"When putting the bulb on a vertical line — always — TAIL END UP! And — when clamped to a horizontal suction line — always TAIL END DOWN."

Does this match what you stated?

I bet the pigtail for the TXV bulb is facing up, or it's upside down on the verticle. Numbers don't look horrible.
I don't think it is NC because your subcooling drops to 3° with a clear sight glass. The only way for it to swing like that is to lose your trap in the condenser... and for the NC to go through the sight glass.
I'm not very familiar with that unit, does it have a microchannel condenser coil? If so, I think your TXV is hunting and it may be slightly overcharged. There's not much room in those coils and when that TXV pinches down, it stacks in the condenser.
Just my 2¢...

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Why did you "condemn" the system and charge the customer $$$,,? What "gave" you that "feeling" that sumpin'was up??

Back it up,CUPCAKE!!!

Can you see NCG on a system that is running??? If yes, then a "system shutdown" might not be required.

There are some nerds out here waiting for an update... well, at least one. I’m interested in knowing if you shut down service valves, ran the condenser motor and checked against pt chart!??

Just curious as to what the discharge temp was, if you checked that.

I found those other problems the next morning after the unit had been running for awhile. The install is about a year old.

Thanks allfor all of the good advice.
The unit is a carrier md 38APD03054A12020
ItÂ’s 2 circuits, with a digital scroll in circuit A
At 100% cir A looks good with steady HP,SP, SH,SC.
IÂ’m going to do the test for non condensables.
IÂ’ll post again afterwards. I also found other problems with the setup options and the way this unit is being controlled. ItÂ’s serving PIU boxes and a VAV air handler, but the unit is configured for 2 stage tstat control C.Type-4. And they had it looking at mixed air temp for control reference. I found the supply air temp was 42 and icing the coils. I told them their control guy needs to set the machine up the right way. As it is setup presently, it canÂ’t unload properly. We were called in after a lot of finger pointing between the installer and the controls company.

Originally Posted by 3.14

I second the thought of letting temperature come to equilibrium with outdoor temp, then checking through a PT chart.

I’m going to keep this in my mental toolbox, because it is non-invasive, cheap, fairly definitave and just makes sense. .. if it is pure... it will be bang on..... if littered with bastard gas or non consumable elements... it will be off.

Good call.

Don’t forget to close the condenser service valves. If you can’t isolate the condenser from the line set and indoor unit, the numbers won’t be accurate.

What brand and model of unit?
Are there 2 txv’s for 1 circuit?
Are there 2 compressors for 1 circuit? (Tandem compressors)

To the OP, Why not finish the troubleshooting? Use the tools and techniques you should have been taught instead of guessing

How old is the machine, has it ever been worked on, probably not but there is a potential of mixed refrgerants if it has been worked on. When was the condenser coil last cleaned. is the filter clean? What are the amps? What is the air delta t across the evap, what is the air delta T across the condensor. Any icing on the evap coil?

Originally Posted by jayguy

You 2 got somethin’ you need to work out?

I think I need to buy him a bottle of Yukon jack lol

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I second the thought of letting temperature come to equilibrium with outdoor temp, then checking through a PT chart.

I’m going to keep this in my mental toolbox, because it is non-invasive, cheap, fairly definitave and just makes sense. .. if it is pure... it will be bang on..... if littered with bastard gas or non consumable elements... it will be off.

Good call.

Originally Posted by jayguy

You 2 got somethin’ you need to work out?

I think we just witnessed a solicitation for sexual favors, but I'm not 100 percent sure.

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You 2 got somethin’ you need to work out?

Originally Posted by psehunter

You get the bank full of cash...

Stick your cash where the sun don't shine, I'll do my "honest but poor" practice every day.

Originally Posted by TechmanTerry

Lets not forget that "I" get "credit/points/coupons" for that big ass job even though it was really only a contactor.

You get the bank full of cash...

Originally Posted by psehunter

Write it up!!! don't forget a LL drier and contactor when you change out the compressor!

Lets not forget that "I" get "credit/points/coupons" for that big ass job even though it was really only a contactor.