30GB075 (carrier chiller)

[HvAckid82]

This is my first time using this site. Anyway I have a customer who has a 30GB075, this equipment is being used in a textile factory. The chiller itself is approx 15 yrs old, has 2 circuits and circuit A has 2 compressors and circuit B has 1 compressor. The unit has 6 condenser fans 2 fans have motor masters, and the other four fans are controlled by temp. Circuit B compressor 1 is the having an "issue". Every Sunday that compressor shuts down on failure code 55 (compressor failure). The compressor is a Carlyle compressor 06E. It is only a yr old with about a total of 2 months run time on it. I know it is the correct model compressor so says the owner’s manual. When I get there to service the unit and check temps, pressure, voltage, amperage etc.
Everything seems ok and here is some info on what I see when I am there. The outdoor temp is 71 and 25% humidity. ECW is 51 LCW is 44 Suction pressure is 65 psi and head pressure is 150 psi. Superheat when temp is checked before the compressor is about 3 degrees. The design is anywhere from 0-5 degrees says the owner’s manual. And when I check thermistors T6 and T8 (I forget off hand) I have 17 degrees superheat. The book says it should be 15-20 I have NO foaming in my oil sight glass so I think it is safe to say there is no liquid going back to compressor. And my sub cooling is 8 degrees.
So what could the problem be all the other compressors run fine and don’t shut down like compressor 1 on circuit B.?
Also what is the best method to check if a thermistor is actually reading the right temp without having to take it out? I know I can do a check to see if it's good or bad but that doesn’t check if it’s reading correctly. Thanks

[heatingman]

you're running a 6 degree approach temp on the evaporator. It looks like your evaporator tubes may be fouled, you should be closer to 0 degree approach. Approach is the difference between your suction pressure temp and the leaving water temp( 65 psi = 38 deg. , so 44-38 = 6 )
I would start by punching the bundle.

Also take the resistance of the thermistor at a known temp value, and check it against the chart for that thermister. Carrier should be able to procure that chart. at X temp Resistance is Y

[heatingman]

also check all electrical connections, and meg out the motor.

[ACCMan]

The compressor failure fault you are seeing is associated with the compressor protection circuit which consists of the high pressure switch (a Klixon type disc), a discharge gas thermostat (likely cause due to problems with this switch listed on factory field repair notices), and a ground fault circuit.
Any split second opening of the safties causes a lock-out.
The discharge gas thermostat has been bypassed on many of these chillers due to this very problem. Depending on vintage of the chiller you are working on you may be having a head pressure problem on start-up. There were several eprom (chip containing the operating parameters) revisions during the early years of these chillers. Some of the first models had a problem with the head pressure tripping during the first few minutes of start-up due to the condenser fans not starting up fast enough. Your local Carrier Technical Rep. can determine by the revision number on the eprom if your machine received the upgrade. The upgrade started most of the fans on start-up instead of allowing the saturated cond. sensor to control the fans.
If you suspect the compressor safety circuit board then swap it out with a board on another circuit. If the problem moves with it.......replace it.
I also can't help but wonder why it only trips on Sunday. Is it controlled by a timeclock? Is the chiller being supplied with a high load on start-up forcing it to go into its non-overloading mode?

[chadcar]

The compressor might be religious and likes a day of rest on Sunday. This happens quite a bit on Mormon units here in Utah.:D

[HvAckid82]

the unit used to have a time clock and when the unit would shut down for the weekend and come sunday the unit would have a high heat load and they would have problems. But now the time clock is no longer being used. I know that on cooler days none of the fans turn on and then a few seconds later the condenser fans that have the motor master would start once the temp would rise. I have a feeling it is the high pressure switch ( i think) but it's very strange that it only happens on sundays. I have ohmed the compressor windings and it seems ok but i have not megged the windings, which should be my next step. Maybe i should bypass the high pressure switch for next sunday and see what happens? i am not really comfortable with doing this.

[gerryboy00]

Maybe i should bypass the high pressure switch for next sunday and see what happens? i am not really comfortable with doing this.


sure :rolleyes: , dont forget to bring a internal relief valve on Monday.......or maybe a compressor!!!



seriously
DO NOT bypass any security control

[heatingman]

rig one of the fans to start before the compessor, and see if that helps, if so update the eprom. also, check the pressure on start, and the temp near the klikson and compare the two.

"The compressor is a Carlyle compressor 06E. It is only a yr old with about a total of 2 months run time on it."

If the compressor is new, then it is possible that there was a little extra oil added to the circuit, and it could be causing your excessive approach temps, and also higher temps at start. initial bearing wash.

[heatingman]

another easy way to narrow it down is with tattle tales ot memory relays to localize the search on the circuit.

[HvAckid82]

when you say initial bearing wash are you suggesting that i am getting liquid in my compressor on start up? I may not be following you, but the oil level is about 1/3 of the sigh glass everytime i am there. And it has no foaming and the crankcase heater works also.
You said about the tatle tails and memory relays. Are these items that i can get from a johnston supply or untied refrigeration. And in this case i want to see if i have high discharge pressure i would need something to go in series with the high pressure switch to see if the pressure switch opens. Right ?

[heatingman]

You should be able to get tattle tales from johnstone, and memory relays are something you can make if tattle tales are not available. a memmory relay is wired like a lock out relay. The coil is paralell to the safety. the N.o contact is wired to allow the coil to stay energized after the pressure switch resets itself. ( if the relay is energized when you return, then the safety tripped )And yes i am suggesting you may be getting too much oil back from the system that is refrigerant soaked at start up. oil has a high affinity for refigerant, and if there is alot of oil sitting in the evaporator, then it has absorbed refrigerant causing it to be non lubricating until the refrigerant boils out of it.

[HvAckid82]

when the unit starts up there is a solinoid that is on the liquid line and is not energized for 10 sec after startup. This helps reduce high amp draw on startup and prevents the cooler from being loaded with refrigerant. I do notice on start up some foaming (not bad compared to some that i have seen) The crankcase heater works and the compressor sump is nice and warm. This foaming action on start up, is it a big problem and if so how am i to correct it?
With my approach being so high on the chilled water side would that cause superheat problems? And i believe the EXV is controlled by superheat after the compressor windings. So more or less no matter what else goes on in the system it will try to maintain the 15-20 superheat (the owners manual says)?

[consolidmech]

I had a similar problem with a 30GB110 unit. On ambient conditons lower than 70 f at startup some times the 2nd stage fans came on too late and tripped on high discharge. However code 55 could be several issues . Narrow it down. Test and makesure the saturated condenser temp sensors are good T3,T4 and are in good contact to refrigeration line .Good contact on CPCS board and relay board low voltage connections. (The feed back signal is only 5 v DC) . As the other thread said you could swap the CPCS board and see. E promp chip is the other culprit. In my case i did change the e promp and so far (5 months) its behaving . Try and borrow the service tool /telibitye 65 converter /lap top from carrier if possible and plug it to J 8 on processor .It wiil make your life easy to trackdown the problem without wasting too much time.

[ACCMan]

You should only bypass a safety when you are there watching the system pressures and operation.
It may be time to call in someone in your area with experience on these chillers. Place a tattle-tale across the high pressure switch if you want to check it. Also do the same on the discharge gas thermostat on the compressor.
I couldn't find any info in your profile about your level of experience.
If you do not have the proper electrical training do not attempt to work on the system.
If you do have the training use the advice listed in my first post with the wiring diagram to troubleshoot the unit.
Or call your local Carrier Tech Rep.

[heatingman]

The high approach will not affect the ability to maintain the superheat, but it will effect the performance, and power consumption. The high approach will cause less heat transfer in the evaporator, causing the exv to close down to maintain the superheat, the closing of the exv will cause backing up of refrigerant into the condensor, and therefor higher pressure on the liquid and discharge line, this may in fact be the root of your trouble, but without a clean evaporator you cant expect designed performance. And with that it's hard to tell if there are any other problems. CLEAN THE TUBES. Small amounts of foaming is ok and normal.

[chiller mekanik]

The high approach will not affect the ability to maintain the superheat, but it will effect the performance, and power consumption. The high approach will cause less heat transfer in the evaporator, causing the exv to close down to maintain the superheat, the closing of the exv will cause backing up of refrigerant into the condensor, and therefor higher pressure on the liquid and discharge line, this may in fact be the root of your trouble, but without a clean evaporator you cant expect designed performance. And with that it's hard to tell if there are any other problems. CLEAN THE TUBES. Small amounts of foaming is ok and normal.

The 30GB is direct expansion. To clean the tubes would require removing all of the refrigerant, cutting the suction lines, disconnecting the EXV's, removing the head, I wouldn't want to brush them with water, then you have to replace that gasket, dehydrate, etc, etc.

I'm not trying to be a wise guy, I'm sure that once you realize that you forgot about the refrigerant being in the tubes, you will want to retract.

[heatingman]

The 30GB is direct expansion. To clean the tubes would require removing all of the refrigerant, cutting the suction lines, disconnecting the EXV's, removing the head, I wouldn't want to brush them with water, then you have to replace that gasket, dehydrate, etc, etc.

I'm not trying to be a wise guy, I'm sure that once you realize that you forgot about the refrigerant being in the tubes, you will want to retract.

No I don't want to retract, the 30gb is a chiller, so it is not dx, it is a chiller clean the damn evap tubes, the waterside dumbass.

[freonrick]

the gb is a direct expansion, it is not a flooded barrell. the water is on the outside of the tubes. to clean them means removing the bundle out of the shell unless chemically cleaning them.

[Carrene #2]

"No I don't want to retract, the 30gb is a chiller, so it is not dx, it is a chiller clean the damn evap tubes, the waterside dumbass."

Heatingman should maybe stick to heating.

[chiller mekanik]

He called me a dumba$$.:eek:

Oh well, I've been called worse.

Hey MODS, you may want to keep an eye on this one, it might be the beginning of a flame war.

I can't respond to heatingman right now (especially any name calling) since I'm too busy ROFLMAO.:D

I'm only here to help anyway, if & when someone can show me I've given bum advice (I given my fair share) I will thank them for setting me straight & move on.

[DBSLLC]

First of all, a chiller with "0 deg approach" has not been built by anyone. The design approach for Carrier chiller barrel is 8 deg, measured with a fully loaded machine and proper(known) waterflow.
Since the compressor trips "every Sunday" suspect high line voltages in the industrial area (it may approach 505V)
Also, the GBs were shipped with the orange jumper for start-stop but most people never removed the jumper when connecting a remote S/S. The machine should have low SST alarms thou.
On the compressor module, remove the current coil from all 3 power leads but do not disconnect from circuit board.
The B circuit may also be sitting idle for a long time and refrigerant will condense under the pressure switch causing it to trip.
Make sure the compressor unloaders ARE Suction cutoff and NOT HG bypass unloaders.

[cateyes]

you're running a 6 degree approach temp on the evaporator. It looks like your evaporator tubes may be fouled, you should be closer to 0 degree approach. Approach is the difference between your suction pressure temp and the leaving water temp( 65 psi = 38 deg. , so 44-38 = 6 )
I would start by punching the bundle.

Also take the resistance of the thermistor at a known temp value, and check it against the chart for that thermister. Carrier should be able to procure that chart. at X temp Resistance is Y

Bingo!

[DBSLLC]

Punching the tubes will only get you a refrigerant leak!:D
WATER IS ON THE OUTSIDE OF THE TUBES.

[DBSLLC]

"the closing of the exv will cause backing up of refrigerant into the condensor, and therefor higher pressure on the liquid and discharge line, this may in fact be the root of your trouble, but without a clean evaporator you cant expect designed performance. And with that it's hard to tell if there are any other problems. CLEAN THE TUBES. Small amounts of foaming is ok and normal."

I'm sorry, I made a promise to myself that I'm going to have to break now. For 10 years I was Equipment/Controls Service Manager for a large mid western Carrier Distributor so when I see some of the concepts about refrigerant flow in chillers being expressed here it makes me understand the sorry shape of this industry overall not just in my neck of the woods.
During normal operation less than 20% of the entire refrigerant charge is in the evaporator.
The barrel actually pumps down at start-up and the unit does not go off on high head since there is plenty of storage space. Increased head pressure is only achieved when there is work being done (expansion Valve opening) and heat is removed from the barrel and compressors. When a machine has high approach temps, the load is reduced and to the extreme of the unit going off on low suction pressure.

By the way the "X/Y" sensor charts are on the left door of the machine and it displays TEMP/VOLTAGE drops. The controls sequence tries to maintain 20dF superheat after the compressor windings. (2-6 after the barrel, 15 after compressor motor).

[ACCMan]

"the closing of the exv will cause backing up of refrigerant into the condensor, and therefor higher pressure on the liquid and discharge line, this may in fact be the root of your trouble, but without a clean evaporator you cant expect designed performance. And with that it's hard to tell if there are any other problems. CLEAN THE TUBES. Small amounts of foaming is ok and normal."

I'm sorry, I made a promise to myself that I'm going to have to break now. For 10 years I was Equipment/Controls Service Manager for a large mid western Carrier Distributor so when I see some of the concepts about refrigerant flow in chillers being expressed here it makes me understand the sorry shape of this industry overall not just in my neck of the woods.
During normal operation less than 20% of the entire refrigerant charge is in the evaporator.
The barrel actually pumps down at start-up and the unit does not go off on high head since there is plenty of storage space. Increased head pressure is only achieved when there is work being done (expansion Valve opening) and heat is removed from the barrel and compressors. When a machine has high approach temps, the load is reduced and to the extreme of the unit going off on low suction pressure.

By the way the "X/Y" sensor charts are on the left door of the machine and it displays TEMP/VOLTAGE drops. The controls sequence tries to maintain 20dF superheat after the compressor windings. (2-6 after the barrel, 15 after compressor motor).

If you are referring to my post of high head pressure trips on start up you should have in your posession a copy ot the Carrier Service News volume 41, item 4, 1988 which states:
The upgrade to a newer version eprom will eliminate nuisance high head pressure trips due to the fact the compressor can build pressure much faster than the temperature of the coil can rise at startup. (The temp. was being sensed on the u-bend of the condenser) The new eprom used the cond. thermistor to measure outside air temp. and to start all of the fans during the 0-1 stage of start-up if the O.A. temp. was above 70 degrees F.
The early 30GB's had many issues with trips related to Code 55.
Code 55 is the problem the Tech asked a question about.
Code 55 is directly related to the compressor circuit protection module and its associated safties.
Other codes cover high superheat, low evap. flow, low superheat, etc.
There are a lot areas that need more info to troubleshoot properly:
Is the water side a closed loop or an open system?
If an open loop, is there a potential for the chilled water to have sediment, cotton dust, rust, mud, or any other foreign substance that can build up between the weir walls in the evaporator section. Once there it is almost impossible to remove without blowdowns installed between every weir.

If you wern't referring to my post............ nevermind...

[heatingman]

I'm sorry, I made a promise to myself that I'm going to have to break now. For 10 years I was Equipment/Controls Service Manager for a large mid western Carrier Distributor so when I see some of the concepts about refrigerant flow in chillers being expressed here it makes me understand the sorry shape of this industry overall not just in my neck of the woods.
During normal operation less than 20% of the entire refrigerant charge is in the evaporator.
The barrel actually pumps down at start-up and the unit does not go off on high head since there is plenty of storage space. Increased head pressure is only achieved when there is work being done (expansion Valve opening) and heat is removed from the barrel and compressors. When a machine has high approach temps, the load is reduced and to the extreme of the unit going off on low suction pressure.

By the way the "X/Y" sensor charts are on the left door of the machine and it displays TEMP/VOLTAGE drops. The controls sequence tries to maintain 20dF superheat after the compressor windings. (2-6 after the barrel, 15 after compressor motor).

Well ok tube punching is not the way to go on this unit, I stand corrected. Never the less there is inadequete heat transfer on the evaporator( hense the high approach), so add blowdowns, and ballance the chemicals, or whatever else carrier would suggest. And closing off of the exv will cause a backing up of refrigerant into the condensor/ reciever, because its not the refigerant in the evap that is the issue, but the lack of refrigerant flow when the compressor runs. This is a recip compressor therefor it is possitive diplacement. Unlike a centrifigal. Why do you supose there are recievers if not to hold the excess refrigerant during low load and pump down? And furthermore we dont know when the failure occurs on start or durring a loaded condition.

[freonrick]

if there is 6 degrees approach on this gb chiller with dx barrell and design is 8 degrees there is no problem with dirty tubes. if he had 15 degrees and not using glycol then ok. even with the newer carrier screw chillers they are running about 3 degrees approach and they are using that to control the expansion valve along with discharge superheat on a flooded barrell.

[heatingman]

if there is 6 degrees approach on this gb chiller with dx barrell and design is 8 degrees there is no problem with dirty tubes. if he had 15 degrees and not using glycol then ok. even with the newer carrier screw chillers they are running about 3 degrees approach and they are using that to control the expansion valve along with discharge superheat on a flooded barrell.

why would the the approach be designed for 8 degrees, that's very inefficient, at trane, we punch tubes anually, and if the approach is over 4 degrees, than we know something wrong. The closer to 0 the better.

[coolperfect]

Code 55 high discharge line temp 150hp anyone stop to check short of gas most common cause hot discharge???

[freonrick]

closer to 0 is better, thats why you see alot more flooded barrells now days on screws and centrifugals. they can handle a little carry over if needed. recips can not handle liquid freon getting in to compressor. it will delute the oil and wash out bearings. the dx barrells are really not made to clean since the water is on the outside of the tubes. it can be done but expensive.

[HvAckid82]

Thanks for all the input. It turns out that there is a time clock used for the chiller. But the time clock was on the 5th floor and the chiller is on ground level outside. Why. I have no clue. I followed the conduit and there she was. SO I jumped it out and runs like a champ for 2 weeks now.