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woot woot i got me a pro title now.

keep water moving both chilled and cooling tower or should say condenser water or you could pop a tube had to retube from finding with edycurent..

Originally Posted by KnewYork

I wanted to comment on this statement as it is patently false. If a chiller is drained without taking the heads off an getting all the water out of the tubes the possibility still exists for freeze bulging and potentially bursting a tube.

One of the principles of the First Law of Thermodynamics is that the flow of heat is from hot to cold. I am stating this hypothetically, however, I have actually seen this occur. If there is residual water laying inside a tube and that tube is submersed in liquid refrigerant when the recovery of refrigerant gas begins the potential of freezing and bulging or bursting that tube is possible. As the pressure in the vessel drops below freezing the water laying in the tube starts to freeze. The rest of the water in the tube that sits outside where the refrigerant envelops the tube starts moving toward the cold area. (Remember hot flows to cold.) The ice ball continues to grow and there is enough water in a tube (even after it's "drained") to form an ice ball big enough to bulge or burst the tube.

I will also state that there are many here who could remove all the charge from a flooded chiller with water in the machine without pumps running and not be at risk of freezing water in a tube. If one understands the prinicple and has a pressure/temperature chart for the refrigerant being recovered it isn't that difficult. I'm not saying this is how it should be done, but it can be done. Running water through the tubes while recovering vapor helps speed the process and is always recommended.

You're absolutely right,

Coincidently enough this topic came up at the office the same day I posted my reply.

Be safe , bring your pressure above the freezing point water then charge with liquid or to recover pull liquid out then let it sit and make sure it's all boiled off above freezing point then goto vapor recovery.

Originally Posted by newbe0507

Yes , 4 years in the trade !!! Is it that easy ?

You need enough posts to verify that you are in the trade. I think that it is 15.

Fill out an application and send it in.

Originally Posted by KnewYork

Why don't you apply for access? You have enough posts. You are a professional, right?

Yes , 4 years in the trade !!! Is it that easy ?

Originally Posted by newbe0507

sorry guys , i dont have access to the pro forum's can we just post here ?

Why don't you apply for access? You have enough posts. You are a professional, right?

sorry guys , i dont have access to the pro forum's can we just post here ?

Thanks guys, great discussion and honestly I’m a little surprised how most techs. don’t know the right way and look clueless when I ask. Not sure if I fully grasp these procedures. I've used the push pull method and basic text book methods but I’d still like to see it done a few times. Funny, 1 guy I asked said he had to pipe in a hot water heater in the barrel to keep the tubes from freezing. Of course I’m sure I looked dumb founded when he said it. I get thrown to wolves on equipment, but a 200 ton chiller is something I don’t want to learn on by making a mistake. It's one thing on a roof top unit but it's totally different when a machine holds 1000 lb's of r22, 134a or r123. Shoot, i think a 1000 lb's of r22 has to be over 10k.

Originally Posted by Nuclrchiller

Best to discuss this in the pro forum. I'll let others explain. I don't type; this reply taking 3-4 minutes. Proper explanation would take me so long, we'd both give up on me. I don't mean to bail out on you, but there would probably be 3 or 4 other answers. And others are better at explaining, too. The big thing to remember is: no liquid to be charged until above saturation temp of 32 degrees. I prefer to wait until 35 degrees or higher, to allow for instrument error.

Dont dig to deep in to that period i was meaning to text my wife. I had to edit.

Originally Posted by KnewYork

One more thing regarding charging with liquid or vapor. There are two dangers when charging with liquid when a chiller is in a deep vacuum...freezing and thermal shock. Look at a PT chart for R-410A for example. At .9" Hg the temperature is -60*F. Imagine what the temperature is at 29" Hg. Even if there is no danger of freezing water one has to be worried about the effects of thermal shock on system components.

In most cases with larger chillers one would be adding the full contents of the cylinder being utilized. So even in the case of blends that are supposed to be charged as a liquid if one were going to charge the entire contents of the cylinder gassing first would not be an issue because everything in the cylinder is going to end up in the chiller. Correct me if I'm wrong on this. The bulk of my experience is with flooded chillers and as of now there aren't any blends that I am aware of that work in flooded applications.

I'm not sure what the "." that Core_d posted meant. Period as in "right" or as in "the end"?

"Thermal shock". Great point KnewYork. I've often wondered about that both during charging in a deep vacuum, and using hot water to heat a low pressure chiller for leak testing. Or rather, reintroducing chilled water into the barrel after the leak test is completed. Have you seen any info on this? When charging, I throttle the vapor valve on the drum to the point that it is slow enough to not frost my hose or my valve, and the rate of pressure increase is "pretty doggone slow". Sorry, but that's the best technical description I can come up with, on short notice. And I agree about charging a blend. And I'm not aware of one either.

I read that post #14 as the "title" being the post. My bad. Thought I was answering a question of how to charge.

One more thing regarding charging with liquid or vapor. There are two dangers when charging with liquid when a chiller is in a deep vacuum...freezing and thermal shock. Look at a PT chart for R-410A for example. At .9" Hg the temperature is -60*F. Imagine what the temperature is at 29" Hg. Even if there is no danger of freezing water one has to be worried about the effects of thermal shock on system components.

In most cases with larger chillers one would be adding the full contents of the cylinder being utilized. So even in the case of blends that are supposed to be charged as a liquid if one were going to charge the entire contents of the cylinder gassing first would not be an issue because everything in the cylinder is going to end up in the chiller. Correct me if I'm wrong on this. The bulk of my experience is with flooded chillers and as of now there aren't any blends that I am aware of that work in flooded applications.

I'm not sure what the "." that Core_d posted meant. Period as in "right" or as in "the end"?

Originally Posted by Core_d

.

Best to discuss this in the pro forum. I'll let others explain. I don't type; this reply taking 3-4 minutes. Proper explanation would take me so long, we'd both give up on me. I don't mean to bail out on you, but there would probably be 3 or 4 other answers. And others are better at explaining, too. The big thing to remember is: no liquid to be charged until above saturation temp of 32 degrees. I prefer to wait until 35 degrees or higher, to allow for instrument error.

Heck, I even worry about these things on a new chiller start up. Concerning what KnewYork mentioned above about residual water, it is surprising how much water can be left in a "drained" tube. Once a tubed has ruptured and let water flood the chiller, a customer will always doubt that chiller's integrity. Even if caught and dried out before further damage is done. I would be sickened to know that I was the cause of such a thing. Never get in a hurry when charging a chiller. It ain't worth it to your customer, and it ain't worth it to your reputation.

what are the proper charging and recovery procedures

.

Originally Posted by Nuclrchiller

I also worry about a restricted tube holding water. Or a slug of mud freezing. Or an incorrectly plugged tube holding water. Basically, I just anticipate the worst possible condition that the tubes can be in.

Beat me to the plugged tubes issue. Unless it is impossible always keep flow while recovering. Obvious reasons, as already pointed out, for this. No reason not too.

Originally Posted by Nuclrchiller

I also worry about a restricted tube holding water. Or a slug of mud freezing. Or an incorrectly plugged tube holding water. Basically, I just anticipate the worst possible condition that the tubes can be in.

Excellent points.

I also worry about a restricted tube holding water. Or a slug of mud freezing. Or an incorrectly plugged tube holding water. Basically, I just anticipate the worst possible condition that the tubes can be in.

Originally Posted by aaron604

In this situation you won't have to worry about freezing your vessel since you've eliminated the water from the system.

I wanted to comment on this statement as it is patently false. If a chiller is drained without taking the heads off an getting all the water out of the tubes the possibility still exists for freeze bulging and potentially bursting a tube.

One of the principles of the First Law of Thermodynamics is that the flow of heat is from hot to cold. I am stating this hypothetically, however, I have actually seen this occur. If there is residual water laying inside a tube and that tube is submersed in liquid refrigerant when the recovery of refrigerant gas begins the potential of freezing and bulging or bursting that tube is possible. As the pressure in the vessel drops below freezing the water laying in the tube starts to freeze. The rest of the water in the tube that sits outside where the refrigerant envelops the tube starts moving toward the cold area. (Remember hot flows to cold.) The ice ball continues to grow and there is enough water in a tube (even after it's "drained") to form an ice ball big enough to bulge or burst the tube.

I will also state that there are many here who could remove all the charge from a flooded chiller with water in the machine without pumps running and not be at risk of freezing water in a tube. If one understands the prinicple and has a pressure/temperature chart for the refrigerant being recovered it isn't that difficult. I'm not saying this is how it should be done, but it can be done. Running water through the tubes while recovering vapor helps speed the process and is always recommended.

Originally Posted by aaron604

Oh I didn't realize this was a specific question from a test. I thought he was looking for generic information.

Probably so but thats my 2 cents.