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Both high and low drop to zero

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jactechcool

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Discussion starter · #1 ·
As in my other thread, just got my 608 about a week ago and learning.

I have a test system, a MovinCool commercial spot cooler. Allready messed up one compressor on it, but thats how you learn.

So, after installing new compressor low side pressure was way low, sat temp of 0-10F. Crazy high SH.

So im thinking, clogged cap tubes (System uses cap tubes, 5 of them to the evap. So i figure, why not...ill take the evap coil out and replace the cap tubes. Will be good brazing practice if anything.

So i took out the evap. Replaced the cap tubes, brazed everything in. Pressure tested with nitrogen for an hour. Vacumed it out for 30 mins. Charged it.

Turn it on. Pressures are at sat temp for ambient. Then the compressor turns on...low side starts to drop, then high side, then they are both at zero in 60 seconds. Turn it back off and pressures return to sat temp for ambient.

I was thinking low charge, but im 100% sure its not low. And i cant see any leaks.

Any ideas?

--John
 
#3 ·
I've never seen a high side drop to zero .... or even anywhere close to it

Are you sure you have your red hose on the high side of the system ?

Something isnt piped right ....
 
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#4 ·
The only way the high side can drop to 0 is if the unit is pumping down where the high side is closed off before where you are reading your pressure.
So either you're reading your high pressure at the wrong place or you've got a restriction upstream of where you're taking the reading.
 
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#6 ·
What was wrong with the unit before you "messed up one compressor already"? That 608 doesn't mean squat until you spend some time working along side an experienced tech. Your philosophy of learning by making mistakes and ruining equipment is bs. Are you being paid for this training? Who's picking up the tab for the compressors, brazing rod etc...? If you had to pay for it out of your own pocket you would be more likely to catch my drift. Would probably also think twice before you start racing to hook your new shiny gauges up. I think that's the real lesson to learn here.
 
#7 ·
Red850kid said:
What was wrong with the unit before you "messed up one compressor already"? That 608 doesn't mean squat until you spend some time working along side an experienced tech. Your philosophy of learning by making mistakes and ruining equipment is bs. Are you being paid for this training? Who's picking up the tab for the compressors, brazing rod etc...? If you had to pay for it out of your own pocket you would be more likely to catch my drift. Would probably also think twice before you start racing to hook your new shiny gauges up. I think that's the real lesson to learn here.
Click to expand...
X2
 
#8 ·
Hopefully this is on your own dime because I think you are putting the cart before the horse. You need to understand the theory completely before you start experimenting on a system. The reason I say that is I have seen how a person who doesn't understand the theory behind what they're working on can come up with some really screwed up conclusions about what the causes of the problems they're seeing are and why their fixes worked. It can lead to a lifetime as a hack.
If you learn the theory first you will begin to understand how it applies to the real world as you work on a system and you will draw more accurate conclusions based on reality rather than based on a lack of information.
For example I know someone who thinks that most systems in the field are overcharged because he sees high head pressure. He also doesn't know that a 10 seer should have different pressures than a 14 seer and how to interpret all the readings to realize that these overcharged systems are actually dirty. A deep study of the refrigerant cycle followed by tinkering and actual field experience will lead to a much better understanding of what is going on.

There are readings that would have told you weather the capillary tubes were really suspect but they are not just pressures you also need several temperature readings.

Sent from the Okie state usin Tapatalk
"Is this before or after you fired the parts cannon at it?" - senior tech
 
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#9 ·
R600a said:
Hopefully this is on your own dime because I think you are putting the cart before the horse. You need to understand the theory completely before you start experimenting on a system. The reason I say that is I have seen how a person who doesn't understand the theory behind what they're working on can come up with some really screwed up conclusions about what the causes of the problems they're seeing are and why their fixes worked. It can lead to a lifetime as a hack.
If you learn the theory first you will begin to understand how it applies to the real world as you work on a system and you will draw more accurate conclusions based on reality rather than based on a lack of information.
For example I know someone who thinks that most systems in the field are overcharged because he sees high head pressure. He also doesn't know that a 10 seer should have different pressures than a 14 seer and how to interpret all the readings to realize that these overcharged systems are actually dirty. A deep study of the refrigerant cycle followed by tinkering and actual field experience will lead to a much better understanding of what is going on.

There are readings that would have told you weather the capillary tubes were really suspect but they are not just pressures you also need several temperature readings.

Sent from the Okie state usin Tapatalk
"Is this before or after you fired the parts cannon at it?" - senior tech
Click to expand...
Well said! It is so true,so very true.
 
Discussion starter · #10 ·
100% on my own dime. Had 4 compressors that came with 2 units I bought for a total of $800. Sold the first unit for $2,300 (it was new unused so it got a good amount).

So yea, it’s out of my pocket, although no matter what I do I’ve actually made money on the deal.

—john
 
#11 ·
jactechcool said:
100% on my own dime. Had 4 compressors that came with 2 units I bought for a total of $800. Sold the first unit for $2,300 (it was new unused so it got a good amount).

So yea, it’s “free” learning for me.

—john


Sent from my iPhone using Tapatalk
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Good.
If you have access to a trane distributor or dealer see if you can get this document. I find it very helpful for learning to diagnose refrigerant side issues.
Image


Sent from the Okie state usin Tapatalk
"Is this before or after you fired the parts cannon at it?" - senior tech
 
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Discussion starter · #12 ·
Red850kid said:
What was wrong with the unit before you "messed up one compressor already"? That 608 doesn't mean squat until you spend some time working along side an experienced tech. Your philosophy of learning by making mistakes and ruining equipment is bs. Are you being paid for this training? Who's picking up the tab for the compressors, brazing rod etc...? If you had to pay for it out of your own pocket you would be more likely to catch my drift. Would probably also think twice before you start racing to hook your new shiny gauges up. I think that's the real lesson to learn here.
Click to expand...
The unit had a frozen compressor to begin with. Learning by mistakes is the way most people learn, even when alongside a very experienced person. As long as it’s coming from your own pocket I don’t see the problem with it.

—john


Sent from my iPhone using Tapatalk
 
Discussion starter · #13 ·
Thanks for the help guys. My gauges are hooked up correctly.

The only thing I can think of is I installed a filter dryer before the process tube which is just before the evap coil. Possibly the filter dryer clogged right away with junk from the bad compressor.

Logic would tell me That would make my high side gauge, being south of it, go low when the compressor turns on.

—john


Sent from my iPhone using Tapatalk
 
#14 ·
jactechcool said:
Thanks for the help guys. My gauges are hooked up correctly.

The only thing I can think of is I installed a filter dryer before the process tube which is just before the evap coil. Possibly the filter dryer clogged right away with junk from the bad compressor.

Logic would tell me That would make my high side gauge, being south of it, go low when the compressor turns on.

—john


Sent from my iPhone using Tapatalk
Click to expand...
That sounds like a very logical conclusion. The question is why was there still junk left in there to clog it?

Sent from the Okie state usin Tapatalk
"Is this before or after you fired the parts cannon at it?" - senior tech
 
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Discussion starter · #15 ·
Good question. Temperature follows pressure so I’ll take a temp reading on both sides of the filter.

—john


Sent from my iPhone using Tapatalk
 
#17 ·
jactechcool said:
Thanks for the help guys. My gauges are hooked up correctly.

The only thing I can think of is I installed a filter dryer before the process tube which is just before the evap coil. Possibly the filter dryer clogged right away with junk from the bad compressor.

Logic would tell me That would make my high side gauge, being south of it, go low when the compressor turns on.

—john


Sent from my iPhone using Tapatalk
Click to expand...
What size FD was installed? I think the advise of knowing the theory ahead of time will save lots of problems and time and money as compared to making guesses in a wild ass guessing game. Thats what a few people advised.
 
#18 ·
Who is most people? This is all your opinion yet you state it like it's a proven fact. If one or more PRO's on this site agrees with "but thats how you learn" then I will shut my pie hole. You can learn from a mistake but that is not HOW you go about learning. That type of mentality is how buildings are burned to the ground and how people are electrocuted to death.

What did you do to damage the first compressor, and what did you teach yourself from it? Process tube is located on compressor body, capillary tube is downstream the dryer! I've never had a dryer plug up within 60 seconds but maybe someone else has. Try to flow nitrogen through the condenser with the outlet disconnected (after you disconnect the bad dryer) . In my case, after slowly building up to almost 400 psi (with the outlet opened up) there was loud pop and some greenish liquid along with a bunch of crud shot 15 ft. out and all over the darn place. That's when I "learned" what killed the old compressor.
 
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