Refrigerant Overcharge

 
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Old 11-04-2010, 10:23 PM   #41
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Re: Refrigerant Overcharge


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Originally Posted by beenthere View Post
You posted that you had a system that had other problems besides being overcharged.

So the overcharge didn't cause the freeze/ice up.
What's the first thing that starts to happen when you overcharge a system?

Does the suction line not drop in temperature? Does frost not start forming on the suction line and suction line service valve? If you don't know, try it next time you have a tank of refrigerant hooked up to a system.

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Old 11-05-2010, 12:46 AM   #42
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Re: Refrigerant Overcharge


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No one said anything about freezing the evaporator. No, an overcharged unit cannot freeze up at the evaporator.

Overcharged units can freeze up along the suction line, at the suction port service valve, accumulator and recip compressors.

After an evap coil freezes up from low air flow; what happens? There is no load on the refrigerant so the normally correct charge becomes an overcharge for the now changed indoor coil air flow. So even in this case, it is the system acting as an overcharged system that causes the outdoor unit components to freeze up. This is what Tranes Snoball was all about.
First off, I was wrong about saying evaporator but none the less I am only expressing a specific point. The first point is that the forum that this was currently posted in is residential. So with that taken into fact, in residential evaporator suction pressure's are above freezing temperature. In the case of an overcharge in a unit with no other problems, the pressure will only go up. Even with saturated liquid flooding back to the compressor, boiling or not , there would not be any freezing due to the high suction pressure caused by the overcharge. Now I would say that you are 100% right about freezing up suction lines, service valves etc. if there was another underlying problem. Also your are 100 % correct that this would happen in refrigeration where a DX coil floods back and suction pressures below freezing would allow iceing as you described. You all seem very knowledgable and Im not saying your wrong I was only considering where the post was posted and by the amount of knowledge of the original poster I highly doubt hes working with 20 ton split system in a freezer.
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Old 11-05-2010, 01:42 AM   #43
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Re: Refrigerant Overcharge


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First off, I was wrong about saying evaporator but none the less I am only expressing a specific point. The first point is that the forum that this was currently posted in is residential. So with that taken into fact, in residential evaporator suction pressure's are above freezing temperature. In the case of an overcharge in a unit with no other problems, the pressure will only go up. Even with saturated liquid flooding back to the compressor, boiling or not , there would not be any freezing due to the high suction pressure caused by the overcharge. Now I would say that you are 100% right about freezing up suction lines, service valves etc. if there was another underlying problem. Also your are 100 % correct that this would happen in refrigeration where a DX coil floods back and suction pressures below freezing would allow iceing as you described. You all seem very knowledgable and Im not saying your wrong I was only considering where the post was posted and by the amount of knowledge of the original poster I highly doubt hes working with 20 ton split system in a freezer.
I'm referring to fixed metered, recip compressor systems 1-1/2 to 5 ton in residential and light commercial applications. Come to think of it, most of the ones I have seen were in light commercial usage, but that is only because they are more prone to be overcharged due to a dirty filter or indoor coil.

I'll have to find the photos I have of a five tonner that is frozen solid from the service valve to the bottom half of the compressor. That one was in Cayman in a school where the maintenance techs had grossly overcharged the system due to not realizing that the evap coil was packed with dust and sand from the recent hurricane that put me in Cayman.
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Old 11-05-2010, 04:00 AM   #44
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Re: Refrigerant Overcharge


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What's the first thing that starts to happen when you overcharge a system?

Does the suction line not drop in temperature? Does frost not start forming on the suction line and suction line service valve? If you don't know, try it next time you have a tank of refrigerant hooked up to a system.
Its not like I never overcharged a system. And no, it didn't frost at the service valve.

UNLESS, there was another issue with the system also. The overcharge itself, did not, and will not cause it to freeze up. There has to be a second problem with the system.

Such as the dirty air filters you listed for commercial systems.
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Old 11-05-2010, 10:19 AM   #45
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Re: Refrigerant Overcharge


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Its not like I never overcharged a system. And no, it didn't frost at the service valve.

UNLESS, there was another issue with the system also. The overcharge itself, did not, and will not cause it to freeze up. There has to be a second problem with the system.

Such as the dirty air filters you listed for commercial systems.
Dirty air filters or any other issue that reduces the amount of air across the indoor coil essentially causes the system to become overcharged for the amount of the load. If you overcharge a system that doesn't have air flow issues, you are doing the same thing; dumping liquid refrigerant into the suction line.

Why would the results not be the same if the same thing is occurring?
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Old 11-05-2010, 10:33 AM   #46
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Re: Refrigerant Overcharge


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Its not like I never overcharged a system. And no, it didn't frost at the service valve.

UNLESS, there was another issue with the system also. The overcharge itself, did not, and will not cause it to freeze up. There has to be a second problem with the system.

Such as the dirty air filters you listed for commercial systems.
This is exactly what Im saying, I completely agree with the man Im just stating that with it being the ONLY problem, freezing up is not possible.
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Old 11-05-2010, 03:31 PM   #47
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Re: Refrigerant Overcharge


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Dirty air filters or any other issue that reduces the amount of air across the indoor coil essentially causes the system to become overcharged for the amount of the load. If you overcharge a system that doesn't have air flow issues, you are doing the same thing; dumping liquid refrigerant into the suction line.

Why would the results not be the same if the same thing is occurring?
Your making a play on wording.

The system is NOT overcharged, just because the air filter is dirty. Its simply a low air flow issue.

And no. If I overcharge a system that doesn't have air flow issues. I have a compressor being flooded. But that doesn't mean the liquid is under 32F
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Old 11-05-2010, 05:35 PM   #48
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Re: Refrigerant Overcharge


lol you guys.....hook line and sinker
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Old 11-05-2010, 06:40 PM   #49
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Re: Refrigerant Overcharge


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lol you guys.....hook line and sinker
The report button, is only to be used to report threads or post that violate rules.

Use other then that, is in itself a violation.
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Old 11-05-2010, 07:02 PM   #50
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Re: Refrigerant Overcharge


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The report button, is only to be used to report threads or post that violate rules.

Use other then that, is in itself a violation.
huh?

who pushed the button
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Old 11-05-2010, 07:12 PM   #51
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Re: Refrigerant Overcharge


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huh?

who pushed the button
Response went into the wrong thread.

So another guy is reading about over charges now. LOL
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Old 11-05-2010, 08:10 PM   #52
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Re: Refrigerant Overcharge


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Your making a play on wording.

The system is NOT overcharged, just because the air filter is dirty. Its simply a low air flow issue.

And no. If I overcharge a system that doesn't have air flow issues. I have a compressor being flooded. But that doesn't mean the liquid is under 32F
I'm not playing with words. I'm trying to show you that the results of liquid returning to the outdoor unit results in freezing no matter what the reason for it.

What the hell is the difference between liquid returning to the outdoor unit because of low indoor air flow or liquid returning to the outdoor unit because of system overcharge?

It is the process of evaporation that absorbs heat and lowers temperature; will you agree with this?

When liquid refrigerant enters the suction line and is allowed to boil off (evaporate), it absorbs the heat in the suction line, reducing the temperature; will you agree to "this"?

Unless a system is so grossly overcharged that the refrigerant stays liquid all the way back to the compressor, and then some to fill up the can of the compressor, anywhere the liquid boils off (evaporates), it absorbs heat and drops the temperature of that component; will you agree with this?

Not just once, but several times, I have seen overcharged units that have formed ice monsters so big around the accumulators and compressors that the ice has buckled the cabinetry of the units. This is usually after years of neglect of a system resulting in one gauge techs topping off the system instead of cleaning the evap coil. Then, another tech notices that their is little air through the system and cleans the coil, but doesn't adjust the charge. Now everything else in the system is proper except that it is overcharged....and it freezes up.

Once a system is so overcharged that there is no evaporation of the liquid refrigerant happening anywhere, it is not going to freeze up but is going to wipe out the compressor.
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Old 11-06-2010, 03:00 AM   #53
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Re: Refrigerant Overcharge


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I'm not playing with words. I'm trying to show you that the results of liquid returning to the outdoor unit results in freezing no matter what the reason for it.

What the hell is the difference between liquid returning to the outdoor unit because of low indoor air flow or liquid returning to the outdoor unit because of system overcharge?

It is the process of evaporation that absorbs heat and lowers temperature; will you agree with this?

When liquid refrigerant enters the suction line and is allowed to boil off (evaporate), it absorbs the heat in the suction line, reducing the temperature; will you agree to "this"?

Unless a system is so grossly overcharged that the refrigerant stays liquid all the way back to the compressor, and then some to fill up the can of the compressor, anywhere the liquid boils off (evaporates), it absorbs heat and drops the temperature of that component; will you agree with this?

Not just once, but several times, I have seen overcharged units that have formed ice monsters so big around the accumulators and compressors that the ice has buckled the cabinetry of the units. This is usually after years of neglect of a system resulting in one gauge techs topping off the system instead of cleaning the evap coil. Then, another tech notices that their is little air through the system and cleans the coil, but doesn't adjust the charge. Now everything else in the system is proper except that it is overcharged....and it freezes up.

Once a system is so overcharged that there is no evaporation of the liquid refrigerant happening anywhere, it is not going to freeze up but is going to wipe out the compressor.
Robin i don't think you are going to win over Beenthere with BS and Brilliance.

you said it your self you love to needle people (and I love to come along on the ride when you do cause it's a lot of fun) but Been is unflappable.

You two will be at it for pages... well considering Been's quiet cool and your biting flamboyance, this might be like watching an irresistible force netting an immovable object:b oxing:
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Old 11-06-2010, 03:10 AM   #54
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Re: Refrigerant Overcharge


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I'm not playing with words. I'm trying to show you that the results of liquid returning to the outdoor unit results in freezing no matter what the reason for it.

What the hell is the difference between liquid returning to the outdoor unit because of low indoor air flow or liquid returning to the outdoor unit because of system overcharge?

It is the process of evaporation that absorbs heat and lowers temperature; will you agree with this?

When liquid refrigerant enters the suction line and is allowed to boil off (evaporate), it absorbs the heat in the suction line, reducing the temperature; will you agree to "this"?

Unless a system is so grossly overcharged that the refrigerant stays liquid all the way back to the compressor, and then some to fill up the can of the compressor, anywhere the liquid boils off (evaporates), it absorbs heat and drops the temperature of that component; will you agree with this?

Not just once, but several times, I have seen overcharged units that have formed ice monsters so big around the accumulators and compressors that the ice has buckled the cabinetry of the units. This is usually after years of neglect of a system resulting in one gauge techs topping off the system instead of cleaning the evap coil. Then, another tech notices that their is little air through the system and cleans the coil, but doesn't adjust the charge. Now everything else in the system is proper except that it is overcharged....and it freezes up.

Once a system is so overcharged that there is no evaporation of the liquid refrigerant happening anywhere, it is not going to freeze up but is going to wipe out the compressor.
Its not the over charge. Its the other things that are causing the freeze up.



Officer. It wasn't me having my foot to the floor that caused my car to exceed the speed limit. it was the fact that I'm driving down a hill, that caused my car to go 140 MPH. Honestly, full throttle had nothing to do with it.
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Old 11-06-2010, 09:04 AM   #55
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Re: Refrigerant Overcharge


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Its not the over charge. Its the other things that are causing the freeze up.



Officer. It wasn't me having my foot to the floor that caused my car to exceed the speed limit. it was the fact that I'm driving down a hill, that caused my car to go 140 MPH. Honestly, full throttle had nothing to do with it.
Really? And here I thought it was liquid refrigerant flashing into a gas that made where ever it changed state the evaporator portion of the unit. And I thought that when an evaporator portion of a unit that had no airflow to create load would drop below freezing to first condense and then freeze the moisture in the air. Is that not what is happening when a unit is overcharged?
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Old 11-06-2010, 09:06 AM   #56
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Re: Refrigerant Overcharge


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Robin i don't think you are going to win over Beenthere with BS and Brilliance.

you said it your self you love to needle people (and I love to come along on the ride when you do cause it's a lot of fun) but Been is unflappable.

You two will be at it for pages... well considering Been's quit cool and your biting flamboyance, this might be like watching an irresistible force netting an immovable object:b oxing:
I can do this for the rest of my life. Hell, I've seen guys who judge that a system is charged when the suction line starts to sweat and determine it is "overcharged" if the suction line frosts.
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Old 11-06-2010, 09:57 AM   #57
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Re: Refrigerant Overcharge


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Really? And here I thought it was liquid refrigerant flashing into a gas that made where ever it changed state the evaporator portion of the unit. And I thought that when an evaporator portion of a unit that had no airflow to create load would drop below freezing to first condense and then freeze the moisture in the air. Is that not what is happening when a unit is overcharged?
Not like your making it out to be.

I can take a brand new unit. Make sure it has 400 CFM per ton air flow, correct. And while operating at an indoor of 75 and outdoor of 85. Slowly add refrigerant until the compressor drowns. And it will not freeze up.

I could add 4 ounces every 10 minutes, and it would not freeze up. Until I changed another condition.

Seen lots of heat pumps that were overcharge in winter. Come summer. They aren't cooling. And they aren't freezing up either.
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Old 11-06-2010, 04:34 PM   #58
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Re: Refrigerant Overcharge


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Really? And here I thought it was liquid refrigerant flashing into a gas that made where ever it changed state the evaporator portion of the unit. And I thought that when an evaporator portion of a unit that had no airflow to create load would drop below freezing to first condense and then freeze the moisture in the air. Is that not what is happening when a unit is overcharged?
Flashing is the result of the refrigerant boiling at a temperature that is above the boiling point for that specific pressure. If you overcharge brand spankin new unit and the suction was 83 psig which would be around 49F, whether it was flashing or not the results would not be freezing up. The reason for the flashing is the ambient temperatures around the pipe are higher than the 49F. So the liquid now occupying the suction pipe is building pressure, becoming warmer and moving its way to the compressor. The main theory of heat transfer is from hot to cold. Would you not agree that with the lower temperature being 49F due to a high suction pressure that temperatures below that would not be achievable. As liquid boils its not the pipe cooling down it is its surroundings exchanging the heat. If you have liquid in a pipe at 83psig equaling 49F, are you saying that as it flashes off the temperature goes down,thats not possible. Its absorbing heat as it is flashing which in turn only makes the temperature go up. The only reduction in temperature is at the point of expansion when a 225psig head turns into a 72psig suction, after that point the temperature and pressure only goes up due to heat tranfer. Take for example charging a system from a fresh vacuum, as soon as liquid exits your gauge port what happens. It freezes up due to the vacuum. Now as soon as the suction pressure rises above 57.8 which would be 32F the ice melts away. The basics of refrigeration still apply no matter what, Pressure relates to temperature. If your ONLY problem was an overcharged unit from a unexperienced tech, the results would be a high head and high suction pressure. If you walked up to a unit that had ice on the compressor, service valves etc would your first thought honestly be overcharge, NO. Now with further investigation you might find exactly what you are saying caused the icing but it would be another problem with the overcharge factor. Not just an over charge. I completely understand what your saying (3rd time saying this) but it seems that you are refusing to understand that this is a very simple question with a very simple answer. Im sure we can all give reasons why a system would freeze up and at this point it would seem that a whole new forum should be created to justify that.

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Old 11-06-2010, 05:56 PM   #59
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Re: Refrigerant Overcharge


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I can do this for the rest of my life. Hell, I've seen guys who judge that a system is charged when the suction line starts to sweat and determine it is "overcharged" if the suction line frosts.
Well I guess now when I hire someone I better ask them what they would assume if they seen a unit freezing up. Thanks for the heads up. I dont think that the first assumption I would want for my techs to have when they saw a frozen up unit in residential is that its overcharged.

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Old 11-06-2010, 07:12 PM   #60
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Re: Refrigerant Overcharge


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Well I guess now when I hire someone I better ask them what they would assume if they seen a unit freezing up. Thanks for the heads up. I dont think that the first assumption I would want for my techs to have when they saw a frozen up unit in residential is that its overcharged.
I absolutely agree that when we see a frozen outdoor unit we do not think first about overcharge. I can also see where in all of the frozen units I have worked on, there were extenuating circumstances leading to the overcharging of the system which ultimately froze up.

Of course, I remedy the real problems before realizing that the systems are overcharged, so I may be associating the systems now being in proper operation except for being overcharged as being overcharged being the reason for them being frozen up.

I think I finally get what you guys are saying and where I am making my mistake in my thought process. Now I have to start overcharging a new system to see if I can get the service valve to start frosting.
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