# Condenser coils going bad



## DCHVAC

Have any of you guys ever had this happen? The first time it happened it took four years to get to the point of failure. All the refrigerant and oil leaked out and the compressor seized. The manufacturer wouldn't give me a new unit so I had to rebuild the old one. They gave me a new coil and compressor. After just one year, it happened again. The original installer didn't use pump ups so I put them on when I rebuilt the unit. This is a heat pump installed in northern Pennsylvania. I'm at a loss to explain this and so is the manufacturer. :001_unsure:


----------



## Swampfox

Do they have a dog?

he might need to find a new spot to go potty


----------



## DCHVAC

Nope....no dog. The manufacturer was thinking along the chemical erosion theme as well. Exterior corrosion doesn't seem likely as there is another identical condensing unit 50 feet away at the in-law unit that has been issue free since installation.


----------



## Swampfox

something corrosive is getting to it, well water maybe? if it has a high sulpher content it will eat up the copper


----------



## scooter

Are those fins corroded?
The pixs look to me like phsyical damage to the aluminum fins?
Did the oil in the bottom come from the coils in the pictured area rotting through?
410A or 22?
Is this the only spot in the condensor or does this line go all the way around?
Scooter


----------



## RoBoTeq

That my friends is what happens when a heat pump does not have enough drainage to keep the bottom row(s) of copper from being crushed by ice.

What happens is that the condensate that drains from the unit during defrost refreezes around the bottom of the heat pump. As the ice builds up, it eventually gets to the bottom row of copper in the finpack.

Now, think about the ice forming around the copper tubing. Water expands as it turns to ice (the only liquid that does so, by the way).

As each defrost cycle adds more ice around the coil, the next defrost cycle turns the ice directly on the coil into water, which drains away until it can not do so any longer due to the ice buildup. This can occur in above freezing conditions because the heat pump coil in the heat mode is extracting heat from the outside ambient air.

Once the area around the tubing fills up with defrosted condensate that cannot drain away from the copper tubing, that amount of condensate...trapped by an outer casing of ice, itself freezes when the heat pump goes back into heating mode.

When that condensate freezes, it now cannot expand outward because of the encasement of ice. So, it expands to point of least resistance, which is the wall integrity of the copper tubing. The copper tubing crushes in on itself as the ice expands. When the copper tubing crushes in on itself, it becomes distorted which wrinkles the aluminum fins that are attached to it.

If you remove the aluminum fins you will find the copper tubing has been crushed into a "C" shape with one side of the tubing crushed into the inside of the other side of the tubing.

Sometimes the crushing of the tubing will create a crack leak and sometimes it will just cause a severe restriction in the coil.

If you are real careful, you can remove the crushed section of tubing and braze in a piece of copper. Remember that finpack tubing is very thin and will burn through with too much heat.

I like to teach what I call the VIAGRA method of remembering to "get your heat pumps up" using pump ups or other means of getting heat pumps up off or pads;
*V*ery
*I*mportant
*A*pplication
*G*reatly
*R*educing
*A*ggrevation


----------



## mechanicalDvr

RoBoTeq said:


> That my friends is what happens when a heat pump does not have enough drainage to keep the bottom row(s) of copper from being crushed by ice.
> 
> What happens is that the condensate that drains from the unit during defrost refreezes around the bottom of the heat pump. As the ice builds up, it eventually gets to the bottom row of copper in the finpack.
> 
> Now, think about the ice forming around the copper tubing. Water expands as it turns to ice (the only liquid that does so, by the way).
> 
> As each defrost cycle adds more ice around the coil, the next defrost cycle turns the ice directly on the coil into water, which drains away until it can not do so any longer due to the ice buildup. This can occur in above freezing conditions because the heat pump coil in the heat mode is extracting heat from the outside ambient air.
> 
> Once the area around the tubing fills up with defrosted condensate that cannot drain away from the copper tubing, that amount of condensate...trapped by an outer casing of ice, itself freezes when the heat pump goes back into heating mode.
> 
> When that condensate freezes, it now cannot expand outward because of the encasement of ice. So, it expands to point of least resistance, which is the wall integrity of the copper tubing. The copper tubing crushes in on itself as the ice expands. When the copper tubing crushes in on itself, it becomes distorted which wrinkles the aluminum fins that are attached to it.
> 
> If you remove the aluminum fins you will find the copper tubing has been crushed into a "C" shape with one side of the tubing crushed into the inside of the other side of the tubing.
> 
> Sometimes the crushing of the tubing will create a crack leak and sometimes it will just cause a severe restriction in the coil.
> 
> If you are real careful, you can remove the crushed section of tubing and braze in a piece of copper. Remember that finpack tubing is very thin and will burn through with too much heat.
> 
> I like to teach what I call the VIAGRA method of remembering to "get your heat pumps up" using pump ups or other means of getting heat pumps up off or pads;
> *V*ery
> *I*mportant
> *A*pplication
> *G*reatly
> *R*educing
> *A*ggrevation


 
I have seen thousands of heat pumps over the years and have yet to see one that would hold 2+ inches of condensate in the bottom, let alone a coil that would be so clogged it holds back water all the way around.


----------



## RoBoTeq

mechanicalDvr said:


> I have seen thousands of heat pumps over the years and have yet to see one that would hold 2+ inches of condensate in the bottom, let alone a coil that would be so clogged it holds back water all the way around.


Sorry you didn't understand my post. I tried to make it as clear as I could.

I did not say that that much condensate builds up. What I said is that an ice dam forms around the bottom of the unit due to there being no where for the condensate to drain off properly.

My guess is that you have simply misdiagnosed a lot of heat pumps that had crushed coils from ice. My comments were not up for interrogation. What I posted is what happens and the only way what caused the problem in that photo to occur.


----------



## mechanicalDvr

RoBoTeq said:


> Sorry you didn't understand my post. I tried to make it as clear as I could.
> 
> I did not say that that much condensate builds up. What I said is that an ice dam forms around the bottom of the unit due to there being no where for the condensate to drain off properly.
> 
> My guess is that you have simply misdiagnosed a lot of heat pumps that had crushed coils from ice. My comments were not up for interrogation. What I posted is what happens and the only way what caused the problem in that photo to occur.


I have 20+ years doing this stuff and have yet to see a heat pump coil damaged like that. And yes as this is an open forum anything posted here is up for debate, isn't that the reason for a forum discussion? Get out and read in some of these forums, it gets nasty at times.


----------



## RoBoTeq

mechanicalDvr said:


> I have 20+ years doing this stuff and have yet to see a heat pump coil damaged like that. And yes as this is an open forum anything posted here is up for debate, isn't that the reason for a forum discussion? Get out and read in some of these forums, it gets nasty at times.


You again misunderstood my post. The reason that this particular issue is not up for debate is because there is only one thing that causes what that photo shows. That one thing is ice damming around the lower coils that eventually crushes those coils.

Just because you have not been aware of this phenomenum does not mean it does not occur. There are no other occurances that will produce what has happened to that coil. I have been over this over and over in the years I have investigated field issues on equipment and I have run into too many techs who refuse to believe what is a fact and the only fact in this particular failure. 

As for my getting out and reading some of the other forums, those who know me know that I am at least in the top ten posters on HVAC forums with over 48k posts on one site alone. I also teach technical troubleshooting and this particular instance is one that has no variation of causes. It is ice, and only ice that causes this problem.


----------



## The Dangling Wrangler

RoBoTeq said:


> As for my getting out and reading some of the other forums, those who know me know that I am at least in the top ten posters on HVAC forums with over 48k posts on one site alone.


 
Yes he is. I'm surprized none of the guys, that post here, (from that site) have said anything.


----------



## RoBoTeq

The Dangling Wrangler said:


> Yes he is. I'm surprized none of the guys, that post here, (from that site) have said anything.


You're a brave soul DW. No one else wants to admit knowing me:no:


----------



## The Dangling Wrangler

RoBoTeq said:


> You're a brave soul DW. No one else wants to admit knowing me:no:


 
And that was only my second post.:laughing:


----------



## beenthere

The Dangling Wrangler said:


> Yes he is. I'm surprized none of the guys, that post here, (from that site) have said anything.


 
I would, but I'm shy. :laughing:


----------



## The Dangling Wrangler

DVR, rest assured, Robo's played in this ball game a few times.:thumbsup:

So has beenthere. 

We're mostly on another site, just ran into these guys by accident.
If they tell ya something,it's the truth.


----------



## Yuri

Must be as old as Moses if he has that many posts. LOL:laughing:
Now sock it to me::boxing:


----------



## The Dangling Wrangler

Some folks get offended by Robo. Mostly because he uses facts to back himself up. Go figure


----------



## RoBoTeq

The Dangling Wrangler said:


> And that was only my second post.:laughing:


 No backing out by pleading ignorance:no:


----------



## RoBoTeq

beenthere said:


> I would, but I'm shy. :laughing:


Oh, I'm sorry, I mistook you for some other guy on another forum. We don't call him shy at all. Sometimes we call him a !


----------



## beenthere

Lots of heat pumps that are set directly on the pad. have that kind of damage done to them.


----------



## beenthere

RoBoTeq said:


> Oh, I'm sorry, I mistook you for some other guy on another forum. We don't call him shy at all. Sometimes we call him a !


 
LOL... Sometimes, he calls himself worse names yet. :yes:


----------



## RoBoTeq

The Dangling Wrangler said:


> DVR, rest assured, Robo's played in this ball game a few times.:thumbsup:
> 
> So has beenthere.
> 
> We're mostly on another site, just ran into these guys by accident.
> If they tell ya something,it's the truth.


By accident? I got an invitation:cool2:. I even went out and bought special clothes to wear for the occasion:euro:


----------



## RoBoTeq

Yuri said:


> Must be as old as Moses if he has that many posts. LOL
> Now sock it to me:


I'm not old.:wheelchair: The name RoBoTeq is actually a conglomeration of varies outsourced persons, mostly in India and Africa and I believe one guy abandoned on an Antarctic outpost. You never really know which RoBo is posting at any one time:chinese::red_indian::arabia:


----------



## RoBoTeq

The Dangling Wrangler said:


> Some folks get offended by Robo. Mostly because he uses facts to back himself up. Go figure


That's about the nicest thing anyone could say about me.

I always thought they were offended by the way I leer at their wives, daughters and moms:brows:


----------



## beenthere

RoBoTeq said:


> That's about the nicest thing anyone could say about me.
> 
> I always thought they were offended by the way I leer at their wives, daughters and moms:brows:


Actually, it was the way you looked at their.

Blue Agave.


----------



## RoBoTeq

beenthere said:


> Actually, it was the way you looked at their.
> 
> Blue Agave.


One should only look at the Blue Agave with reverence and awe:notworthy:


----------



## The Dangling Wrangler

RoBoTeq said:


> One should only look at the Blue Agave with reverence and awe:notworthy:


 
Does it have to be done with a mirror, like the Medusa? :shifty:


----------



## beenthere

RoBoTeq said:


> One should only look at the Blue Agave with reverence and awe:notworthy:


See, they though you were bowing to their daughters and wives. LOL


----------



## scooter

I dont want to get everybody riled up but I'm still in need of some more explainaition.
In the pic it looks like the damage is in a thin line. no crush above the line and no damage below. so is there a "puddle" laying in the bottom and the ice layer on top of the water doing the damage? There also does not look like enough damage to the aluminum fins to "c-crush " the tubing.
curious?
Things that make you go HHMMMM!
Scooter


----------



## RoBoTeq

scooter said:


> I dont want to get everybody riled up but I'm still in need of some more explainaition.
> In the pic it looks like the damage is in a thin line. no crush above the line and no damage below. so is there a "puddle" laying in the bottom and the ice layer on top of the water doing the damage? There also does not look like enough damage to the aluminum fins to "c-crush " the tubing.
> curious?
> Things that make you go HHMMMM!
> Scooter


Have you removed the wrinkled fins from the coil yet? I'm not sure how I can explain it any better. Ice formed around the coil tubing and crushed it. The section of damaged coil may be able to be bypassed, but in most cases the best thing to do is to install a new coil after getting the unit set up off of the pad.


----------



## The Dangling Wrangler

Might be time to retire that unit. Unless I missed it, how old is this baby?


----------



## RoBoTeq

The Dangling Wrangler said:


> Might be time to retire that unit. Unless I missed it, how old is this baby?


No way would I even think about replacing that coil if the unit is out of warranty. Also, if the tubing has cracked enough to pull in air if the system went into a vacuum, the compressor has also taken a beating.

If the system is under warranty, condemn the coil, compressor and reversing valve and see if the distributor won't use the costs of those items against a new unit.


----------



## scooter

Robo 
I am not the guy that started this post. I am just a casual observer that sees things in the photo that do not agree with your explanation. 
I see a condensing unit from the inside 
I see a bottom corner of the coil.
Approxamately 2" up from the bottom pan on the coil itself, I see a line of damaged aluminum fins that seem to be bent from left to right, as if someone took a screwdriver and ran it around the inside of the coil in an effort to bend all the fins over. there is no damage to the aluminum above the "screwdriver" line and no damage below the line. there is liquid in the bottom of the pan that could be oil or water or coke or any other fluid.
My question was. If the damage was done by ice then how was the damage isolated and confined to this one thin line 2" above the bottom of the coil with no damage above or below?
Scooter


----------



## mechanicalDvr

RoBoTeq said:


> Have you removed the wrinkled fins from the coil yet? I'm not sure how I can explain it any better. Ice formed around the coil tubing and crushed it. The section of damaged coil may be able to be bypassed, but in most cases the best thing to do is to install a new coil after getting the unit set up off of the pad.


 
If you have a copper tube that is surrounded by ice in an open coil, why would the ice exert force on the tube rather than to the outside away from the coil? There is no containment here. The only reason expanding ice blows holes in copper pipe from the inside when it freezes is because there is no other place from the force to go. This theory makes no sense to my way of thinking.


----------



## scooter

That is my point also. If the ice has somewhere else to go it will certianly push in the direction of least resistance.


----------



## RoBoTeq

mechanicalDvr said:


> If you have a copper tube that is surrounded by ice in an open coil, why would the ice exert force on the tube rather than to the outside away from the coil? There is no containment here. The only reason expanding ice blows holes in copper pipe from the inside when it freezes is because there is no other place from the force to go. This theory makes no sense to my way of thinking.


OK, I have been through this over and over many times with those who want to argue about this. This is not a theory, it is what happened to that coil. I'm sorry if my being so absolute about this bothers you, but this is what happened; ice formed around the copper, crushing it, causing the distortions of the fins.

Now, let's see if I can describe how that occurs better;

during a defrost cycle, the coil heats up causing a melting of frost on the coil. That frost is now water which makes its way from the entire coil surface to the bottom of the unit. The bottom of the unit is not heated, so if the water cannot easily drain away from the unit, it refreezes.

After many defrost cycles, the water draining off of the coil builds up ice from the bottom of the unit up the coil. The ice will eventually form both inside of the unit as well as outside of the unit.

As more and more defrost cycles dump more water to the bottom of the unit, the ice eventually builds up to and then above the level of the bottom row of copper tubing in the coil fin pack. Once the ice has formed on both sides of the copper tubing, actually to the copper tubing, each subsequent defrost cycle melts the ice which is now trapped between the ice forming on the inside of the coil and the ice forming on the outside of the coil.

Once the ice has formed completely around the copper tubing, the next defrost cycles are pouring water around the copper tubing with no where to escape to. So now, each defrost cycle creates a water filled cavity around the copper tube, surrounded by solid ice. When the system goes back into the heating mode, that copper tubing gets cold enough to freeze the water that is now trapped in the ice encasement around the copper tubing. As the water surrounding the copper tubing freezes, it expands. Since it now cannot expand outward, because of the encasement of ice, it expands inward to the weaker copper tubing, crushing the tubing.

I sure hope I've made it easier to visualize this time because I just don't know how else to explain this phenomenum. There is no other force that can crush copper tubing and if the fins are removed from the copper tubing you will find that the tubing has been crushed. The tell tale sign that this has occured is the type of distortion that is shown in that photo. Nothing else can do this.


----------



## johncavh

the only unit i every saw with damage like that was a heat pump that was not mounted on pumps.


----------



## RoBoTeq

scooter said:


> That is my point also. If the ice has somewhere else to go it will certianly push in the direction of least resistance.


once the copper tubing is encased in ice, the point of least resistance is the copper tubing. It may take a few defrost cycles to completely crush that tubing, but it will do so.

In rare occasions I have seen copper tubes near the top of units where the fan shroud is do the same due to solid ice forming at the top of the unit. This usually happens to units that are located under overhangs.

The result of this damage is not usually found until a time when the weather is above freezing. The reason is that in the heat mode, the back up heat keeps the HO from realizing that anything is wrong until they get their electric bill.

So, most times there is no sign of ice around the unit when the tech is called out to check out why the unit is not operating properly. When the cause of a problem vanishes before the problem is noticed, we start looking for ghosts. This is one ghost we have identified.


----------



## RoBoTeq

johncavh said:


> the only unit i every saw with damage like that was a heat pump that was not mounted on pumps.


That is the most likely candidate for this type of damage.


----------



## scooter

Why are the fins damaged in a thin straight line 2" above the pan?
Why are there no damaged fins below the thin line?
Why are the fins bent/damaged from a force pushing from inside the condensor, out?
I completely understand the phsyics behind freezing water and the damage that it can cause. 
From the situation you are describing, the coils/fins should be destroyed from the bottom all the way up to the line?


----------



## RoBoTeq

scooter said:


> Why are the fins damaged in a thin straight line 2" above the pan?
> Why are there no damaged fins below the thin line?
> Why are the fins bent/damaged from a force pushing from inside the condensor, out?
> I completely understand the phsyics behind freezing water and the damage that it can cause.
> From the situation you are describing, the coils/fins should be destroyed from the bottom all the way up to the line?


The fin damage is caused by the distortion of the copper tubing, not by the ice that encased it. The only area of fin distortion is going to be where fins are attached to the damaged tubing that is now out of round.


----------

