Trane Voyager Problem

[kroy]

I've been servicing a 20 ton Trane Voyager for a surgical center for about three years. Before the last summer a U-bend on the circuit 1 condensor coil leaked bad and I repaired it. Sometime just before the winter started I was called out and found the compressor on the same ciruit was equalized. I replaced the compressor which was under warranty, and after doing so the system basically pumps down as if there was a restricted filter drier or TXV. I weighed the charge in, the head is very low the subcooling is high and the superheat high. I replaced the guts of the TXV, and the filter drier but the problem is still there.
Has anyone else had a problem like this? I was reading another thread that was similar, but it ended without a solution. My next approach is to isolate the coils and try to determine if they are clogged, but was hoping to get feedback before undertaking such a costly repair and end up getting fired.

[acwizard]

Is this a heat pump. Taking some temperature readings along the refrigerant piping will help to determine where the restriction is located.

[CFC Mafia]

I have about 50 of these units that we rent out to to US Military for desert field training. What has happened to some of my units is if the evaporator load is really high or if the head pressure is high. The oil will thin and the compressor will push the oil into the condenser and eventually some will make it into the evaporator. Whats bad is if the compressor fails from lack of lubrication. If the oil is not drained out of the condenser, it will act like it is overcharged. The head may hit 400 within seconds and running like that will kill the second compressor. Your problem though is like the evaporator is oil logged. Can you see if any of the feeder lines of off the TXV are not as cold as the others? I have had to cut the lines on the bottom of the evaporator and condenser and just let nitrogen blow out any oil that would drain. I got a gallon out of one unit one time.
Just my experience, good luck.

[kroy]

It is not a heat pump, but it does have a hot gas reheat coil for dehumidification. I do not have any significant temp drops along the liquid line, and there is no flashing except after the txv.

[AiResearch]

I've been servicing a 20 ton Trane Voyager for a surgical center for about three years. Before the last summer a U-bend on the circuit 1 condensor coil leaked bad and I repaired it. Sometime just before the winter started I was called out and found the compressor on the same ciruit was equalized. I replaced the compressor which was under warranty, and after doing so the system basically pumps down as if there was a restricted filter drier or TXV. I weighed the charge in, the head is very low the subcooling is high and the superheat high. I replaced the guts of the TXV, and the filter drier but the problem is still there.
Has anyone else had a problem like this? I was reading another thread that was similar, but it ended without a solution. My next approach is to isolate the coils and try to determine if they are clogged, but was hoping to get feedback before undertaking such a costly repair and end up getting fired.



Does the 20 - ton Voyager not have a liquid header / multi-orifice at evap coil? You say txv. I dont remember an expansion valve on that unit. We need some more information. Anything you can put down will help. Temps , pressures , SH , SC , model #'s , comp #'s , It may require another visit to the jobsite and gather the data. With that , you will receive solid ideas.

[acwizard]

Is this the circuit with the hot gas .

[kroy]

it is definitely a TXV, which I rebuilt. The back pressure will bounce from 0 to 25lbs with a superheat temp of 45 to 55 degrees. The head never exceeds 180lbs even with the fan off with a subcooling temp of about 65 to 55 degrees which would be a subcooling of about 30 degrees. Obviously my refrigerant is just sitting in the condensor chilling out.
I do not have the model numbers on me. But one thing that is strange is that the compressor is a Copeland, from the factory. Trane verified that when I used the warranty to replace it. Compressor #2 is a Trane.

[kroy]

This is the circuit with the bypass valve, but it is not open. The discharge is going to the condensor.

[acwizard]

What is the model number

[acwizard]

Have you checked the amps on the compressor

[kroy]

No I dont have the amps. But since I have the LP jumped out to do the readings, it doesnt take long for the compressor to open due to no return gas.

[acwizard]

Is the scroll running the wrong direction

[kroy]

No definitely not, it was for a second when I first hooked it up but I reversed it immediately.

[dandyme]

Hold the bus need to know a couple things

1- you changed a compressor because it was "equalized"?


2- you have this unit running with LPCO bypassed???

[kroy]

Ok Ok The compressor change out might have been a little hasty, but when my first tech out said he heard cluncking and had no compression ratio, I didnt question it and knew it was under warranty. They replaced the compressor and I got called out for the problem I'm dealing with now. I should have investigated further but I am proud to be the first one to EVER make that mistake!
The LPCO is only jumped out very temporarily so I could assess the problem and take temperature readings. Im not the sharpest knife in the drawer, but I'm not a spoon either.

[acwizard]

I believe Trane uses a reversing valve (simalar) for the hot gas . Your problem is in the hotgas circuit.

[Dchappa21]

Did you change the power head when you changed the guts on the txv.

[kroy]

But how so? I keep thinking it is a suspect, but I cant figure how the valve would create low suction pressure if it wasnt working correctly. I can feel the hot discharge gas going through the valve and out to the condensor and not to the reheat coil. Besides wouldnt that raise my suction pressure?

[kroy]

Yes, I changed the power head too.

[acwizard]

Kroy, It has been awhile since I have seen a Trane unit with reheat. Describe in detail the piping circuit and all valves in reheat . There usually two valves, a check valve possibly or single 4way valve. Which setup do you have.

[kroy]

The discharge from the compressor goes into the three way valve. One outlet of the valve goes to the condensor for normal operation, and the other goes to the reheat coil. After it exits the reheat coil ( and at this point has condensed) it goes through a check valve into a tee on the liquid line and then goes through the TXV and the evaporator coil. So its basically a heat pump and cooling at the same time.

[AiResearch]

So we have a starved evaporator , with low suction pressure and high superheat , we also have low head pressure , even with condenser fan off. You weighed the charge in. The problem circuit has a Copeland scroll. The other circuit a Trane 3-D im guessing. And they are equal capacity? 10 tons? Did that txv look factory? And the unit has hot gas reheat and not hot gas bypass to evaporator. Correct?

[AiResearch]

Okay so confirmed hot gas reheat coil. Good piping explanation. And that valve is not energized and hot gas not flowing to the reheat coil during problem right?

[AiResearch]

Are you sure your not undercharged? What is your OAT? But you say high subcooling , usually not an indicator of low refrigerant level. This is an R-22 unit right? Coils clean and airflow good? Did you try adding gas? What is the other circuit doing? Dumb question....was the cond panel on during readings? Are you sure that new comp is the right model?

[kroy]

AiResearch, that is correct. The valve is not in reheat. The TXV looks original.

[AiResearch]

it is definitely a TXV, which I rebuilt. The back pressure will bounce from 0 to 25lbs with a superheat temp of 45 to 55 degrees. The head never exceeds 180lbs even with the fan off with a subcooling temp of about 65 to 55 degrees which would be a subcooling of about 30 degrees. Obviously my refrigerant is just sitting in the condensor chilling out.
I do not have the model numbers on me. But one thing that is strange is that the compressor is a Copeland, from the factory. Trane verified that when I used the warranty to replace it. Compressor #2 is a Trane.

Liquid line temp 65 to 55 degrees? Subcooling 30 degrees? So your condensing temp is 95 to 85 degrees , or about 160 to 190 psi liquid pressure. Okay. Is it an adjustable expansion valve? A Sporlan? Or one of those small OEM Alco jobs without any adjustment? What is your load on the evaporator?

[acwizard]

Do you recall how much refrigerant you added.

[kroy]

It is a 22 system. I believe the compressor checks out. On the two days I was there, OAT varied between a warm day of 80 degrees and a cool day of 50 - 55, but the results were basically the same. I left the panel off once on purpose and shut the fan down to try and intentionally raise head pressure. The charge is exact and then some for further testing. But with the high subcooling I know that that 22 is enjoying a nice long stay in the condensor.

[acwizard]

I think there must be a strainer ahead of txv that is restricted.

[kroy]

ACWizard,
22.3lbs.
I might as well throw this in the loop. Im not sure if the reheat valve is supposed to be open or closed when energized. It has 24 volts to it but does not react either way if disconnected. I know from the temp that it is closed to the reheat and that was my only concern at the time. I have no literature on the valve, and it is not in the diagram with the unit.

[acwizard]

Where did you take your high side reading, liquid line or discharge

[AiResearch]

I think there must be a strainer ahead of txv that is restricted.

You may be right Mr. Wizard. But what is the good circuit doing? Has this unit ever ran right? I have seen a mis-circuited condenser coil before.

[acwizard]

Looks as if charge is correct , catalog showed 21.3 lbs. You may have another bad txv , would not be the first time I have seen that. I was wondering if reheat valve is stuck in mid position or check valve is leaking.

[kroy]

Where did you take your high side reading, liquid line or discharge

Discharge. No port on liquid line. I will try and find a strainer on the txv.

The unit ran ok for three years with the exception of the leak on the cond. coil.

[AiResearch]

Looks as if charge is correct , catalog showed 21.3 lbs. You may have another bad txv , would not be the first time I have seen that. I was wondering if reheat valve is stuck in mid position or check valve is leaking.

Yup! Usually a new powerhead will let refrigerant flow. Ive been having them loose their charge a lot lately. On these little heat pumps where the capillary vibrates and buzzes from a rotary comp. What it sounds like. Refrigerant stacking in the condenser.

[kroy]

Looks as if charge is correct , catalog showed 21.3 lbs. You may have another bad txv , would not be the first time I have seen that. I was wondering if reheat valve is stuck in mid position or check valve is leaking.

I had the same thought about the TXV and the reheat valve. So the biggest problem I think I'm having is all of the variables.
Do you think it would be a bad idea to just eliminate the reheat circuit? It is a VAV system with local hot water reheats, so I dont really need it.

[acwizard]

Kroy, Try taking the bulb off and put it in a bucket of hot water and see if anything changes. Trane has been using some cheap txv lately. Trying to copy York with all of their problems.

[acwizard]

I had the same thought about the TXV and the reheat valve. So the biggest problem I think I'm having is all of the variables.
Do you think it would be a bad idea to just eliminate the reheat circuit? It is a VAV system with local hot water reheats, so I dont really need it.

The reheat is for dehumidification where the reheat coils in the vav boxes are for heating.

[kroy]

Kroy, Try taking the bulb off and put it in a bucket of hot water and see if anything changes. Trane has been using some cheap txv lately. Trying to copy York with all of their problems.

Yeah I tried that. I even tried adjusting it all the way open. No change. It seems like a massive restriction, but yet when I have the system open for these repairs I blow nitrogen through everything and there seems to be no problem

[acwizard]

Did you try to energize reheat and observe pressures

[kroy]

The reheat is for dehumidification where the reheat coils in the vav boxes are for heating.

I know. I just meant that since the unit runs constant 5o degree SAT in the summer anyway it does a pretty good job dehumidifying. And the reheats can keep the temp up. I work on a bunch of other exact application Voyagers without the reheat coil. But I dont think it is related to this problem anyway. A different headache.

[kroy]

Did you try to energize reheat and observe pressures

well it is energized but not open. When I disconnect it stays the same. I get confused sometimes with the Trane because I dont know if it is one of those snubber circuits that show only potential voltage.

[AiResearch]

Yeah I tried that. I even tried adjusting it all the way open. No change. It seems like a massive restriction, but yet when I have the system open for these repairs I blow nitrogen through everything and there seems to be no problem

OUCH. That explains quite a bit. Sounds like you have done a lot before coming here. Too much solder in a joint? I would yank that puppy out and put a nice adjustable Sporlan in its place , remove the guts and head , heat paste and carefull brazing , new drier. Maybe re-use the gas if you have a clean recovery jug with a good evacuation on it.

[acwizard]

Kroy, I am assuming that you changed the liquid line drier when you changed out the compressor.

[AiResearch]

And while the system is open , re-do your nitrogen blow thru test to re-confirm no other restrictions. That shotgun approach should take care of it. They need this unit going dont they.

[AiResearch]

You said there was little TD on the liquid line. Your feeder tubes after the distributor are COLD and maybe frosting. There you go. Thats your pressure drop.

[kroy]

And while the system is open , re-do your nitrogen blow thru test to re-confirm no other restrictions. That shotgun approach should take care of it. They need this unit going dont they.

Yeah they sure do. these medical accounts are a *****.
I never soldered in the new TXV just changed the guts and the powerhead. So there should be no clog from that. I replaced the LL Filter right after the compressor was changed.

I was thinking of opening up the inlet to the condensor and the liquid line and blowing through it with the nozzle, and then doing the same with the evap through the distributor on the TXV and the outlet. What do you think?

[kroy]

You said there was little TD on the liquid line. Your feeder tubes after the distributor are COLD and maybe frosting. There you go. Thats your pressure drop.

But isnt that where I'm supposed to have my pressure drop?

[AiResearch]

YES! But in this case it is too much pressure drop , because your metering device is well , not metering enough! What I meant was , we need to look and find where your major pressure drop is , if we are talking about a restriction. You know? Low side fluctuating from 0 to 25 lbs? Major pressure drop from 180 right. And yes , I would blow backwards from the suction line at the evap back through the feeders and distributor in reverse , just to be sure.

[kroy]

Point well taken! I think i was refusing to believe that it could be the txv since it was new.

I really appreciate you and ACwizard taking the time to help me out with this. I normally just read stuff here and never post. It is good therapy to talk to guys who clearly know their ****.

[AiResearch]

You would have to cut the suction line , and test is done with no txv in place , and sure why not do the condenser at the same time? It's only a few couplings and a days work for the total job including evacuation. New txv , drier , couplings , evac and re-charge with fingers crossed. Im not sure about that reheat valve my friend. As far as operating. I dont think its your problem now since you took temp readings across it. If its a 3 way valve and not a 4 way , then its probly a solenoid and not a sliding piston. Unwire it for now until the other problems are corrected? Assuming it is energized during a call for reheat.

[AiResearch]

Point well taken! I think i was refusing to believe that it could be the txv since it was new.

I really appreciate you and ACwizard taking the time to help me out with this. I normally just read stuff here and never post. It is good therapy to talk to guys who clearly know their ****.

Your welcome. No problem at all kroy. You may be the one to bail us out on the next one. Yes , there are some sharp guys on this site for sure!

[AiResearch]

kroy you did good on that one! A lot of people come here without trying much , and then dont have any solid information to go off of. You did everything most of us would have done , sometimes it is just another set of eyes. good luck with it.

[kroy]

[QUOTE=AiResearch;9698012]

Even though I didnt sweat the TXV you think I should still change it? I know that sounds bad or lazy, but I am probably going to eat it cost wise as well as the drier, since i wont be able to bill them twice.

[kroy]

kroy you did good on that one! A lot of people come here without trying much , and then dont have any solid information to go off of. You did everything most of us would have done , sometimes it is just another set of eyes. good luck with it.

Thanks! Much appreciation. Forget that last question. I know I have to do it. You win some and lose some, (or in my case lose most)

[acwizard]

Kroy, The only thing here which still is a bit of concern is that the pressures should have changed slightly with the reheat coil energized.

[AiResearch]

Thanks! Much appreciation. Forget that last question. I know I have to do it. You win some and lose some, (or in my case lose most)

Well wait a minute. You could try another powerhead. Dont even have to open the system for that , and if you do it while its running the 25 pound low side , it wont spew as much through the pushrods. Darn pck units with no service valves or pumpdown. You might also take valve apart and check for sticking and oil pushrods if it has them. I know what ya mean about parts cost. Thats a tough one. If time is on your side you could tinker with it.

[AiResearch]

Its also possible that they gave you the wrong cage assembly , spring too heavy...

[acwizard]

Kroy, AiResearch has given you a lot of good advise. These problems can be a bit frustrating but we all learn from the jobs that are a challenge. There may not be a financial reward here but knowing your skills allowed you to solve this problem will better you in the future. Good luck , let us know how you make out.

[AiResearch]

Kroy, AiResearch has given you a lot of good advise. These problems can be a bit frustrating but we all learn from the jobs that are a challenge. There may not be a financial reward here but knowing your skills allowed you to solve this problem will better you in the future. Good luck , let us know how you make out.

And so has acwizard. Yes that is how we grow in this business. You never stop learning. And yes let us know!

[kroy]

Kroy, AiResearch has given you a lot of good advise. These problems can be a bit frustrating but we all learn from the jobs that are a challenge. There may not be a financial reward here but knowing your skills allowed you to solve this problem will better you in the future. Good luck , let us know how you make out.

Will do.
Thanks again for the support.

[929rc51]

Hey Kroy, someone all ready mentioned it but the screen filter that is supposed to be on the inlet of the TXV... were you able to get to that when you did the rebuild? I would do as these brilliant gentleman said and replace the TXV but make sure you check that screen and replace. I had a 50 ton doing all most the same stuff to me I swore up and down it was a clogged condenser tube I took temps all over that damn thing. Finally talked to tech support and the guy said he was certain it was a bad power head. I took the TXV off and cleaned out any debris, pulled a vacuum and have never had a problem since with it.

Oh and another tip go to your local supply house and get the neon orange brazing rod(its neon orange flux), It will make your replacement VERY much easier, that stuff flows like soft solder and doesn't take much heat.:cheers: and good luck. Let us know how she turns out.

[kroy]

[QUOTE=929rc51;9702402]Hey Kroy, someone all ready mentioned it but the screen filter that is supposed to be on the inlet of the TXV... were you able to get to that when you did the rebuild? I would do as these brilliant gentleman said and replace the TXV but make sure you check that screen and replace. I had a 50 ton doing all most the same stuff to me I swore up and down it was a clogged condenser tube

Thanks for the advice. I never heard of that brazing rod you mentioned but it sounds great.
In the repair that you did, did you replace the whole TXV or just the power head? The thing that got me was, I was convinced it was the powerhead and replaced it and the guts, but I was not able to get to the screen. I didnt think it was the screen because when I had it apart I had no trouble blowing through it.

[929rc51]

Thanks for the advice. I never heard of that brazing rod you mentioned but it sounds great.
In the repair that you did, did you replace the whole TXV or just the power head? The thing that got me was, I was convinced it was the powerhead and replaced it and the guts, but I was not able to get to the screen. I didnt think it was the screen because when I had it apart I had no trouble blowing through it.[/QUOTE]

I got lucky and didn't have to replace either one. I pumped the unit down and took the TXV off and cleaned it out, it was risky(and probably stupid/lazy) on my part but it worked... this time. In the future though I think it would be good practice to replace the whole assembly if there is any suspicion of either one, unless there is absolutely without a doubt no question that its the power head.