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Non-condensables diagnosis

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AreEyeSee

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Discussion starter · #1 ·
Came upon a R22 walk-in cooler today at an indiapendant convenience store. According to them a few months ago someone came in and stole all of the copper off the unit and the unit was left open for well over a week. Not an accurate timeline but it's hard to get a complete story. Well they had someone come in and re-pipe the system and charge it up.

Now a month later I show up for a call saying the unit is tripping the breaker. Reset the breaker and go out to start the unit to see if I can get any indication as to why it's tripping the breaker. First time flipping the disconnect at the unit nothing came on and tripped the breaker on the panel inside. Reset the breaker and disconnected the ultra start that someone put on it to replace the potential relay on the unit. Flipped the disconnect and cond fans and comp came on pulling LRA so I shut it off. Reconnected ultra start and flipped disconnect and comp and cons fans both came on.

Suc 60
Head start off around 275 and rise.
Amps start off at 17 and rise.

So after the unit ran for a good min or two I noticed the head was steadily rising and got well over 400psig and was still rising. The amp draw went from 17-23. At this point I shut the unit off. I checked the cond coil for debris and it was fairly clean. I'm not sure how to check for discharge air recycling but it could be possible on this unit with it's covering.


Next thought was non condensables so I disconnected the compressor and let the fans cool the cond coil. Waited for dschg and LL to cool and took readings and both were at 92.8-93 as was air entering the cond coil. Pressure for the coil was at 185 with a saturation of 96. According to the test I should have been down around 174-175psig.

Can I get some thoughts on my readings and diagnosis? Much appreciated


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#2 ·
Never had a noncondesables issue but you may try shining a flashlight though the condenser. See if you have light, what was your suction like? I would guess that the increased head pressures would cause an increased suction pressure. Seems odd that it just started tripping breaker now and not after system was repiped. If conder is for sure clean, evacuate, change drier and recharge, if still.tripping breaker find out what is tripping the breaker by comparing nameplate specs and what each component is pulling for amps.

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#3 ·
I would double check the calibration of my gauges with a jug of virgin refrigerant at the same temperature.

If you find the 175psig that you expect to find, then I'd go ahead and recover, evacuate and recharge.

You could also use a megger on the compressor to check for moisture in the system, but some have said it has fleeting accuracy.

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#4 ·
Mooshman812 said:
Never had a noncondesables issue but you may try shining a flashlight though the condenser. See if you have light, what was your suction like? I would guess that the increased head pressures would cause an increased suction pressure. Seems odd that it just started tripping breaker now and not after system was repiped. If conder is for sure clean, evacuate, change drier and recharge, if still.tripping breaker find out what is tripping the breaker by comparing nameplate specs and what each component is pulling for amps.

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Click to expand...
Meant change drier evacuate then recharge.

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Discussion starter · #5 ·
Mooshman812 said:
Never had a noncondesables issue but you may try shining a flashlight though the condenser. See if you have light, what was your suction like? I would guess that the increased head pressures would cause an increased suction pressure. Seems odd that it just started tripping breaker now and not after system was repiped. If conder is for sure clean, evacuate, change drier and recharge, if still.tripping breaker find out what is tripping the breaker by comparing nameplate specs and what each component is pulling for amps.

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Click to expand...
Did check cond coil with flashlight and it was visible through much of the coil. Suction stayed about the same. Wish I had more time to look into this unit but it was late in the day.
 
#7 ·
AreEyeSee said:
Btw sight glass was kinda yellowish. Sometimes those things can be hard to differentiate color wise.
Click to expand...
I think yellowish means noncondensables on sporlan sights, green is ok, it should say on the glass itself, recommend removing charge changing drier and deep evac. I will find the lit....

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#11 ·
AreEyeSee said:
Came upon a R22 walk-in cooler today at an indiapendant convenience store. According to them a few months ago someone came in and stole all of the copper off the unit and the unit was left open for well over a week. Not an accurate timeline but it's hard to get a complete story. Well they had someone come in and re-pipe the system and charge it up.

Now a month later I show up for a call saying the unit is tripping the breaker. Reset the breaker and go out to start the unit to see if I can get any indication as to why it's tripping the breaker. First time flipping the disconnect at the unit nothing came on and tripped the breaker on the panel inside. Reset the breaker and disconnected the ultra start that someone put on it to replace the potential relay on the unit. Flipped the disconnect and cond fans and comp came on pulling LRA so I shut it off. Reconnected ultra start and flipped disconnect and comp and cons fans both came on.

Suc 60
Head start off around 275 and rise.
Amps start off at 17 and rise.

So after the unit ran for a good min or two I noticed the head was steadily rising and got well over 400psig and was still rising. The amp draw went from 17-23. At this point I shut the unit off. I checked the cond coil for debris and it was fairly clean. I'm not sure how to check for discharge air recycling but it could be possible on this unit with it's covering.
View attachment 491341

Next thought was non condensables so I disconnected the compressor and let the fans cool the cond coil. Waited for dschg and LL to cool and took readings and both were at 92.8-93 as was air entering the cond coil. Pressure for the coil was at 185 with a saturation of 96. According to the test I should have been down around 174-175psig.
Click to expand...
Even if the difference was due to noncondesables they're only adding 10psi to your head pressure, so that isn't the problem. It's most likely overcharged.
 
#13 ·
Don't be so sure the coil isn't dirty. Put a hose on it and rule it out (to easy to do).
MAKE IT A HABIT to read SH at every job. For whatever reason, most people that I have worked with or around over the years don't use this tool. It's like trying to surf without a board! It doesn't make sense. It will tell you everything you need to know.
Rule out the simple things before diving in to deep. Don't over think it. I say that because I tend to do it from time to time. ( just ask pecmsg ) lol.
 
#14 ·
See if it was "re piped" correctly with correct line sizes. Then tell them you have to evacuate ,changE drier and recharge in order to continue to work on it and diagnose.

Lara sounds like compressor is also dying.
 
Discussion starter · #15 ·
Moonray said:
Don't be so sure the coil isn't dirty. Put a hose on it and rule it out (to easy to do).
MAKE IT A HABIT to read SH at every job. For whatever reason, most people that I have worked with or around over the years don't use this tool. It's like trying to surf without a board! It doesn't make sense. It will tell you everything you need to know.
Rule out the simple things before diving in to deep. Don't over think it. I say that because I tend to do it from time to time. ( just ask pecmsg ) lol.
Click to expand...
Haha yeah I tend to assume the worst case scenario right off the bat. I will take super heat measurements from now on. I need to get into a routine of taking down readings. On a system that's split like this where I'm on the outside of the building and cooler is on the inside obviously best place to take a reading is from exit or the evap correct? No readings off exterior piping? I always get worried if I have to do that while the comp is running at such high head. I feel like it's going to blow up or something while I'm inside taking readings.



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#16 ·
AreEyeSee said:
Haha yeah I tend to assume the worst case scenario right off the bat. I will take super heat measurements from now on. I need to get into a routine of taking down readings. On a system that's split like this where I'm on the outside of the building and cooler is on the inside obviously best place to take a reading is from exit or the evap correct? No readings off exterior piping? I always get worried if I have to do that while the comp is running at such high head. I feel like it's going to blow up or something while I'm inside taking readings.



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Click to expand...
The best place to check is exiting the evaporator when the box is close to designed temp. MFGs are different with these readings, but I look for 6 to 10 degrees. You can also read at the pump. I look for 20 to 40 degrees, depending on the length of the line set.
 
#17 ·
Moonray said:
Don't be so sure the coil isn't dirty. Put a hose on it and rule it out (to easy to do).
MAKE IT A HABIT to read SH at every job. For whatever reason, most people that I have worked with or around over the years don't use this tool. It's like trying to surf without a board! It doesn't make sense. It will tell you everything you need to know.
Rule out the simple things before diving in to deep. Don't over think it. I say that because I tend to do it from time to time. ( just ask pecmsg ) lol.
Click to expand...
I wish this site had a way to give a thumbs up when I see good advice... I like what Moonray has to say whole heartedly.

Start with the basics and then move on.
some of the signs of Non condensible look similar to blown suction valves and sometimes it is difficult to recognize. So before you jump into the Crazy stuff always hear Moon Ray in the back of your head saying LOOK at the simple stuff first!

Defiantly Megohm the compressor after you wash it.

Non condensible will gather at the top of your condenser and it will essentially reduce the capacity of condenser. You can connect on your discharge line right b4 it enters the condenser and reclaim some of the gas. Personally I would reclaim it all. Perform a triple sweep with nitrogen after I changed out the drier and then put new gas in it. Let it pull down to proper temp and then check the txv bulbs and then check super heat.
From the looks of the picture I would be wary of how much I billed this guy. The work I just described could amount to 800 - 1100 depending on the amount of gas
 
#18 ·
The sad thing is, I have Moonray in my head ALL THE TIME. It's not pleasant! Every now and again I will say something worthy of remembering. As most of you know in here, I haven't been doing this as long as some. I'm still learning something new everyday.
The best advice that I could give to some of the newbies of this site, is to READ all the threads you can and pick up some of the habits the REAL pros use. There are quite a few veterans in here that REALLY know their shat and are wiling to share it with YOU.
PAY ATTENTION!!!
PEACE V
 
Discussion starter · #20 ·
Sorry to say I did not get to return to this unit another guy I work with went back and said he recovered some of the charge and the unit was cooling when he left. Out of my hands now. :(


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AreEyeSee
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