Unusual problem

[wulff]

Hi, you guys have been very helpful in the past but I have a strange thing happening that makes no sense (to me!)
As I have been saying I am working on an ice bank water chiller. It was using a Copland 1 horsepower compressor and 134a. I installed a new expansion valve and Enviro-Safe HC refrigerant.
It had POE oil in it (I just found out water got into the system) and ruined the compressor. I installed a new 3/4 hp compressor with a moisture gauge that had alkybenezen oil and a new drier and like an idiot I used too much oil.
It started to slug up the condenser and I could hear surging at the expansion valve.
I took your guys suggestion and blew the condenser, evaporator, etc with nitrogen to get rid of excess oil.
I put just enough refrigerant in it to trigger the pressure switch and let it run for awhile (hoping any extra oil will return to the compressor).
It didn't get very cold because of not having very much ref in it.
But here is the weird thing, at the output of expansion valve the temperature was 62 degrees F and stayed there but when I shut the valve in the liquid line leading to the expansion valve the temperature starts dropping and getting colder (it even frosted the lines!) when I open it up the output starts to heat up! (there is an adjustment on the valve but it doesn't seem to do anything!)
Should I adjust the expansion valve? Should I remove the balance tube? I know I need to add a lot more ref. but why is this thing acting so strange?
I am thinking of going to an orifice, remove the balance tube and relocating the cycling switch (I have more experience with orifice systems) and I think the expansion valve is causing my problems.
I doesn't matter if it makes ice, I just want cold water for my machines and roots vacuum pumps.
PLEASE HELP, tell me what I am doing wrong! How can I build this to simply make cold water?

[nike123]

Put bulb of expansion valve in ice cold water and see if expansion valve closes.
What is new refrigerant full name?
What is expansion valve full model number?
What is orifice size.
Did you adjusted TXV to factory setting by counting turns or measuring with slide rule?
What is compressor model number?

[Gary]

If I understand correctly, you closed the liquid line valve and the liquid line cooled. That's normal.

[wulff]

Put bulb of expansion valve in ice cold water and see if expansion valve closes.
What is new refrigerant full name?
What is expansion valve full model number?
What is orifice size.
Did you adjusted TXV to factory setting by counting turns or measuring with slide rule?
What is compressor model number?
Thanks for your continued support Nike.

1. I will try the bulb in the ice water. The expansion capillary tube is a KT-43-JC with 60" tube.

2. It is called Enviro-Safe 12a Industrial refrigerant (it is a mix of iso-butane and propane.

3. the expansion valve is a Sporlan with the number EBQE on the side. (I'm not sure of the orifice size).
I didn't change the factory settings of the expansion valve).

4. The compressor is a 3/4 horsepower Tecumseh AJ100GT-193-J7 (I used to work there as a Tool and Die Maker ):)
Thanks Nike,
Best regards, Phill

[wulff]

If I understand correctly, you closed the liquid line valve and the liquid line cooled. That's normal.

Hi Gary, the liquid line doesn't get cold when it I turn the valve off the expansion valve and evaporator gets cold.
Also, the solenoid has an adjustment on it.... why would this be adjustable?
Thanks,
Phil

[Gary]

Some solenoid valves have a manual stem which can be used to open them in case the electric coil fails.

[Gary]

Are there any devices between the evaporator coil and the compressor?

[wulff]

Are there any devices between the evaporator coil and the compressor?
There is an accumulator about 4" in diameter and about 12 inched tall. It is just an empty can with a dip tube that goes onto the compressor, actually there are two of these, one is on the high side right before it goes to the Sporlan filter-drier. That is why I used a lot of oil as I thought these would capture the excess oil.
I was wondering if excess oil is still migrating through the system as it has been running for about 3 hours and about every hour or so the compressor will start vibrating really badly then it will quiet right down!
Should I either blow out more oil or add an oil separator in the liquid line?
Thank for all the helpful tips Gary, they are appreciated!!
Best regards,
Phil

[Gary]

The tank on the high side is a receiver. It's purpose is to store surplus liquid refrigerant. It does not store surplus oil, nor should the accumulator.

Is the bottom of the compressor cold?

[nike123]

That is why I used a lot of oil as I thought these would capture the excess oil.

No, it won't.
Dip tube in acumulator has small hole in it which ensures oil return.
http://product-image.tradeindia.com/00249930/b/0/Refrigerant-Suction-Accumulator.jpg

You say that you have both expansion valve and capillary tube. Could you elaborate more on that.

[Gary]

And what is a "balance tube"?

[FEISTY]

Gary, if the info he gave on the TXV valve is correct it appears it is externally equalized. That's probably what he means by balance tube. You know how it goes. Ask 6 contractors what a part is and you get 6 different answers.

[FEISTY]

By the way...what was reason behind changing from original 1hp Copeland compressor to 3/4hp Tecumseh ??

[wulff]

Thanks guys, the reason I changed the compressor was the original was rattling like crazy!
The 3/4 Tecumseh isn't working out because it vibrates so bad I am going with another 1.5 hp Copeland (They won't go for buying a new one since we have dozens of used Neslab coolers on hand and they don't want me to spend the money!
I was looking at the Neslab HX-150 I pulled the Copeland out of and noticed it has a capillary tube instead of an expansion valve. But here is the weird thing, it has 2 tubes instead of one, is this normal? I can see where you would get the drop in pressure but by using 2, does it increase the amount of refrigerant?
I have never seen a system with 2 capillary tubes (they are both about 30" long and are simply soldered between the filter/drier and the evaporator (which is just a large 1/2" coil of tubing in the supply tank water).
Could I use this capillary system on my other chiller to replace the touchy 'balanced' expansion valve?
I have to get this thing making cooling water before Friday.. so, I could really use some of your thoughts.
Thanks, Phil

[Gary]

I hardly know where to start. The engineers at the factory went to a lot of trouble to make sure all of the components were properly matched to each other and to the refrigerant/oil used in the system.

You have changed the refrigerant, changed the oil, changed the TXV (without even knowing the orifice size), changed the compressor... and who knows what else. Each of these changes can drastically alter the balance of the system. All of these changes combined add up to a nightmare.

[Gary]

For starters, you should reinstall the original TXV and switch back to the original refrigerant.

[Gary]

On second thought, since the oil has already been changed, if the enviro-safe is a direct replacement for the R134a then stay with the enviro-safe.

Is the enviro-safe a direct replacement for R134a? Is it compatible with the oil you have put in the system?

[Gary]

To properly match the condenser, the compressor must be the same capacity. If going to a different compressor capacity it is better to be slightly undersized than slightly oversized. Since the original was 1 HP, the 3/4 HP is a less problematic choice than the 1 1/2 HP... although the original orifice in the original TXV may then be oversized for the smaller compressor.

[wulff]

Thanks Gary, I am still using the original expansion valve (well, I am using a new one with the same number) the capillary question was just I was wondering if it would be better than the EV.
The EnviroSafe is a drop-in replacement for 134r and can use mineral or synthetic oil. I cleaned it all out and used Alkybenzene 200 (which was used on the replacement compressor).
So, there is no way to use the motor with 1/2 more HP than the original?
Neslab mixes and matches different hp compressors on their chillers with the same evaporators (the coils in the water) but these are all water cooled instead or air-cooled condenser so maybe that's how they do it?
Thanks again Gary.

[Gary]

BTW, where it says on the label how much refrigerant to put in the system... you might as well forget that. When you make changes, this no longer applies. You now have no idea how much refrigerant to put in the system.

[Gary]

Does the TXV have the same orifice size as the original?

[Gary]

Did you clean the air cooled condenser?

[wulff]

BTW, where it says on the label how much refrigerant to put in the system... you might as well forget that. When you make changes, this no longer applies. You now have no idea how much refrigerant to put in the system.

LOL, that's true.. in fact the company that built the chiller has told me different amounts everytime I call them. It is marked as 13 lbs so I thought that was a lot so I called and the gal said that unit should have 14 lbs. a few weeks later I called back to verify and she said the tech was building one and she would ask him and came back with 8 lbs, I called later about something else (a valve) and thought I would ask again and was told 'about' 15 lbs! So I decided to go with pressure/temp since they don't seem to know!
I will check the condenser as it isn't easy to get to the front as the chiller is about 8" from the wall and I can't see the condenser. I take a large fan to blow air against the wall as the area is in a small room and I tell every one not to ever close the doors!

[Gary]

Cleaning the condenser is extremely important.

[Gary]

On the original TXV, there should be a KT number on the top of the power head. What is that number?

If you remove the power head, the cartridge below it is color coded. What color is the ring on the top of the cartridge?

[wulff]

On the original TXV, there should be a KT number on the top of the power head. What is that number?

If you remove the power head, the cartridge below it is color coded. What color is the ring on the top of the cartridge?

It is a Sporlan TEV and marked KT-43-JC
around the edge it says: R12-134a-401a
If I remember the ring was blue

[Gary]

It is a Sporlan TEV and marked KT-43-JC
around the edge it says: R12-134a-401a
If I remember the ring was blue

Are these the same on the new TXV?

[wulff]

Yup, the valves are identical. There is an adjustment on the bottom but I was told under no circumstances should this be adjusted. Isn't this just a 'fine-tune' as the metering 'valve' is pre-determined and will flow only what it is designed for?

[nike123]

Yup, the valves are identical. There is an adjustment on the bottom but I was told under no circumstances should this be adjusted. Isn't this just a 'fine-tune' as the metering 'valve' is pre-determined and will flow only what it is designed for?
Adjustment should be done after replacement. Original valve is also adjusted after commission.
And that cover most of the cases when valve should be adjusted.

[Gary]

I would disagree, Nike. The TXV adjustment should be left as is unless/until it has been proven that adjustment is needed.

[Gary]

Yup, the valves are identical. There is an adjustment on the bottom but I was told under no circumstances should this be adjusted. Isn't this just a 'fine-tune' as the metering 'valve' is pre-determined and will flow only what it is designed for?

Did you clean the condenser yet? Also clean the fan blade and make sure the fan runs in the right direction. The condenser needs all the airflow it can get.

[nike123]

I would disagree, Nike. The TXV adjustment should be left as is unless/until it has been proven that adjustment is needed.
Good point , but I think that factory setting of TXV doesn't cover all cases and it should be adjusted to value of superheat which is suitable to particular case. If factory setting is matching particular case, than adjustment isn't needed.

[Gary]

Good point , but I think that factory setting of TXV doesn't cover all cases and it should be adjusted to value of superheat which is suitable to particular case. If factory setting is matching particular case, than adjustment isn't needed.

While I would agree that fine tuning may be needed, this system has serious problems that need to be addressed before this is done. Until the rest of the system is working properly, the TXV should be left as is. Even then, I would question the OP's ability to make the fine tuning adjustments.