EXV problems on Carrier 30GT Chiller

[hvac-alan]

Hello John:

The Model and Serial number are:

30GT130610KA #4496F38497

I am going back Tuesday to go through the EXV troubleshooting guide that Carrier provides, but wanted to verify that I had the correct EXV----if not, then pumping the unit down and taking off the powerhead would be a waste of time until I got the correct Valve.

[ac eagle]

No,change in colors for the Exv cable same as old cable. As for your sensors I did the same and still could not believe bad sensors,but if your confindent then go with it..did you check for probalby restricted cores????

[hvac-alan]

Hey ac eagle:

I changed the core driers, I had a 4 degree drop across the drier plus we still had a little water in the system due to the cracked chiller barrell (the sight glass was yellow). I am going to change again on Tuesday. Sight glass is green, but not as green as the other circuit.

I certainly will not rule out the sensors, but like I say, as I was watching the sensors, ie the superheat went over 75 degrees, I would have expected the EXV to open up, but it was closed and the compressor was pulling the system into a vaccum. Same when I had 0 superheat, I would have expected the EXV to close some to raise the superheat, but it did not. The board will allow these conditions to exist for 5 minutes without locking compressor out. The exv did not react to the temperatures that I was seeing. My monitoring system was a little crude because I have to sit there and keep checking the two sensors with a DC volt meter then look at the chart that I photocopied to convert to temperature, so I might have missed some flucuations, but it is my thinking that the EXV should have reacted to the temperatures that I was seeing and it actually reacted the opposite that I would have expected.


Wire colors: I am going to check continuity of the cable and insure that white and brown were reversed, because that is what the last tech did when he changed the cable, he crossed white and brown???

[millerbug42]

Originally posted by hvac-alan
I am the third tech put on this chiller 30GT 130. Problem is that Circuit B shuts off on High Superheat, then sometimes Low Superheat, and occasionally low oil. All sensors are good. Their are two new compressors on Circuit B, New EXV, new chiller barrell. It seems as if the EXV does the opposite that it should. The previous tech told me that the EXV wire colors changed on the new EXV (brown and white??). Going back on Tuesday to run through the Carrier EXV troubleshooting guide. Any further suggestions. I am the junior guy in our shop, would like to find the solution to his growing headache.

I have had 3 differant parts go bad on this model chiller over a 5 year period. #1 driver board fuse #2 driver board and #3 processor board.. All three times the same diagnostics was just like your discription of problem.

Don Miller

[mmc]

I believe the name of the software you're talking about is Flotronic Manager. It's a DOS program that I run in WIN 98. The beauty is that you're able to see what the microprocessor sees. You may think the setpoint dial set at 45 but when you run FM, you see that the Micro is seeing the setpoint at 38 or 55 or whatever. Your voltage drop might tell you it's seeing 75 degree SH but when you run FM, you might see that it's only seeing 29.

It's a great program and it really helps troubleshoot the chiller. No more guessing. Get the ground loop converter and get connected.

[hvac-alan]

Thanks mmc

I havent got the converter yet, but I have the instructions to connect to the J8 plug. Do I hook the converter to my 9 pin serial port???? Where do you connect yours. Also, will this program work with XP, I have opened it in XP and manuvered to the temperature screen, but I am not connected to the microprocessor board.

[joeywpittman]

can you email me that program
Thanks
joeywpittman@hotmail.com

[hvac-alan]

You should have it. Let me know.

Alan

[hvac3901]

me too me too,

[Edited by hvac3901 on 09-05-2005 at 11:45 AM]

[hvac-alan]

I do not think that I have a driver board on this unit. The micro processor controls the exv directly. But just in case I am misinformed, what are you calling the driver board?? and where is the fuse??? It would be great if it was just a fuse.

Presently, I have 3 possible culprits:

1. The board or software that controls the exv
2. The exv or maybe the wrong exv
3. The wiring to the exv, --the cable

Of coarse, still could be the thermistors, but I haven't seen that. Some are new.

I think that the driver boards came with Flowtronic II, this unit is Flowtronic I. Any input on this assumption??

[hvac3901]

i sent you an email, had a little trouble on my end of it with outlook. could you please send one more time

[hvac-alan]

You should have it now. I sent the program to ultimatehvac.com. Hopefully he will be able to post in on the internet so I can link it in this post. I am no computer guru, but I think that it would be helpful since several people have indicated an interest in the program. Perhaps some that have actually used it can give some more detailed instructions on hooking it up. If the program works as I have been told, it will be very helpful and save a bunch of time.

[hvac3901]

to the best of my knowledge you do have to use the older windows version for alot of carrier stuff, i believe it has to do with com port settings and conflicts.

hooking it up is no problem, just use the designated connection and three wires out of a standard phone cable, rj-11. i dont remember the exact connection points / colors. i will look into it i think i might be able to find it, besides that i thought it was mentioned in the o&m

[mmc]

OK hvac-alan,

First contact Telebyte @ 800-835-3298. Order a M/N 65A or you can go to their website ( http://www.telebyteusa.com ) and order it. It is an external powered Ground Loop Converter. Power it up per the directions in the box.

When you start Flotronic Manager, on the first page on the right side it tells you how to connect. You're going to connect from plug J8 on the Flotronic to the Telebyte 4-20 GLC so follow that connection diagram. Connect two wires to your 6 pin plug at pin number 3 and 6 then connect the other end to your GLC at C+ and C-. Don't worry, everything is labeled. It sounds harder than it really is.

Once you get wired, just plug in your 6 pin connector onto plug J8 on the board and plug your GLC into your laptop. I use a 25 X 9 pin converter then a gender bender to get to my serial port.

Fill in M/N and S/N and your name for operator ID then make sure all your configurations are correct then press Enter. If you are communication correctly, the cursor will rotate every few seconds.

It shows Entering Water Temp, Leaving Water Temp, Leaving Water Setpoint, Cir A and B Ret Gas Tmp, Sat Sct Tmp,Superheat, EXV Calibration, EXV actual Position, Sat Cond Tmp, Liq Line Sol, and if your oil pressure switch is made. It shows which compressors are running: A1 A2 A3 A4 B1 B2 B3 B4.It also shows which fans are running on Cir A and Cir B. It also shows any alarms. Like I said, its a great little program. You see exactly what the microprocessor is seeing.

Good luck. Let me know if you have any other questions.

Mark Mc

[hvac-alan]

[QUOTE]Originally posted by mmc
[B]OK hvac-alan,

Once you get wired, just plug in your 6 pin connector onto plug J8 on the board and plug your GLC into your laptop. I use a 25 X 9 pin converter then a gender bender to get to my serial port.

MMC

That is great information. The above is the part that I am not clear on. I have a nine pin serial port adapter that I use for Comfortview. Can I use a phone cord to connect from this adapter to the Model 65A????? I suppose it may be clear once I get the converter, but wanted to ask while things were still fresh.

[hvac-alan]

Earlier I stated that the EXV motor I needed was a 760 step motor. Now I am not so sure since I have found some Carrier literature that indicates that the motor has 1500 steps. Does anyone have some info on this??? Both EXV's have been replaced. Circuit B's exv has been replaced recently, then the motor fried and that was replaced last week. Want to verify that I have the correct step motor.

[mmc]

The answer is NO. The Ground Loop Converter replaces the serial port adaptor that you use for Comfortview. And you cannot use a phone cord for Flotronic Manager. This is really OOOOOOOOOOOOOOld stuff.

Like you said, once you get the GLC, you'll see. You plug the GLC into your serial port with the help of a few adaptors that I mentioned. Then you connect your two conductor wire to the C+ and C- terminals on the GLC. At the other end of your two conductor wire, you connect your red and black wires to pin number 3 and 6 on a 6 pin female recepticle that will plug onto the J8 plug on the microprocessor. I know you can get the 6 pin female plug from Carrier. I just found an empty plastic bag in my bag of cables with Carrier Pt # HY 06AM 017 Then it says "Terminal" under the part number so I think that part number is correct. Once you get the plug on the end you are ready.

It goes like this: laptop serial port to the GLC. GLC to the two conductor wire. Two conductor wire to the six pin female plug. Six pin female plug plugs on to the plug J8 on the microprocessor.

If you're anywhere around Houston, TX, it would be alot easier to show you than it is to try to explain it. It really is easier than it sounds if you have all the correct parts and pieces.

Good luck and stay in touch.

[hvac-alan]

MMC

You have been a great help. You have filled in the part that I did not understand. I haven't been in commercial too long (1 year) and most of the guys in my department are far more advanced in chillers, but my niche is that I know a little more than they do about computers--i am looking forward to broadening their horizons a bit, like they have done for me. Accessing the board in this manner will be something that none of them have done.

Thanks again. I am in North Carolina but if I can't figure it out I may have to come to Houston--but a suppose right now accomodations are alittle limited.

[ac eagle]

Did you or any other tech from your company replace exv board?? do you have one exv board or one for each circuit??? if singular board switch circuit b and a and see if your exv operates properly that would tell you if you have a bad board... I would suggest replacing the sensors only cause that you and I saw the same sitution not saying your wrong... Please keep me inform with this chiller would love to get more information and help in any way possible... Are you base in Mass??? if not where??? just an fyi.

[hvac-alan]

Hey ac eagle

The board has not been replaced. Though it may turn out that it needs to. The literature and several guys on this site have mentioned an exv driver board. I am fairly certain that I do not have one, but I will double check tomorrow. The exv cable is plugged directly into the J7 plug of the microprocessor board.

Sensors:

I should have mentioned much earlier when you brought it up that many of the sensors have been replaced. I know both cooler saturation sensors have been replaced along with the LWT. I also think that the return gas for Circuit B was replaced, but not certain. I am confident that they are reading correctly, but I will not completely rule it out because so many people, including you have seen odd things with the sensors.

Location:

I am in Raleigh, North Carolina. How is your summer going in MA, it has been a hot busy one here.