Trane CVHE 045 Help!!!

[pipingpro]

Ok chiller gods! Here is a stumper (very long story)

Trane 1984 circa CVHE045 (400 ton)

Last November we looked at a chiller that another company tore down because the machine was not running. We are not sure how the machine ran before they tore it down, but one thing we knew they added about 60 gallons of oil over a period of time saturating the eliminators so bad they were sucked up in the vanes.

We cut a section of the evaporator out and replaced the frames and put new eliminators, complete teardown with new bearings, oil pump, vent line solenoid, new CH530 purge, new pressure switches and tang assemblies.

We started the machine and had several issue's with the tower fans in which the owner fixed so we had the correct condensor water flow.

After the work on the teardown was done we installed a pinberthy cleanup filter system on it and it has picked up some residual grime and rust. The machine was open to the atmosphere for several months until they contracted us to do the repairs.

After all this the machine started for about 2 minutes and then shut down on low evap temp. We pulled the charge and weighed it back in (it was ok). It appears that the refrigerant is stacking up in the condensor. The condensor
water temp is ok, the flow rates thru the chiller are ok per Lacrosse, but the evap temp drops down to 30 degrees in two minutes. We tried choking the condenser water flow down to increase the condensor temp and that didn't help.
We pulled the economizer and the orifice's were not plugged and drilled a hole in the bottom of the economizer and that orifice was not plugged. We welded that plug back in and before we hooked up the economizer on we tried looking at the spray tree on the ends but can't see down even with a scope. We tried running the machine unloaded but it won't even allow us to do that. We are going to try and put a clear hose on the evap shell top and lower valves to see what the liquid levels are. One note, we did not replace the tubes but had an eddy current on them and the tubes were clean when they eddy current tested them.

The only thing I can think of is the spray tree but when I looked in the evap hole from the economizer the holes that I could see, everything looked perfect??

Any idea's???? Anyone ever had this problem?

[txhvac]

You've given alot of info. can you give pressures/temps, what type of refrigerant, condenser/evap temps, etc. This can help narrow down questions.

[absrbrtek]

What are your temps comming out of the cond ll thru to the last metering plate going intgo the evap? Are either of your economiser vent lines excessively cold? I would be checking for abnormal temp drops in that area. There is a weir at the condensor outlet that could possibly plug up with crap if it was large enough. You need to hook up multiple temp probes before starting it again. The temp drops will tell all.

[pipingpro]

I didn't have time to record pressures when the machine was running in the short time, because this is another tech's job and I just have been the muscle on the job.

I know that the evap temp went down to 29 degrees (I forgot to take out my thermometer out and had the probe hanging!! OOOOPS

I will post the temps tommorrow, I will call the primary tech for the the log sheets. I checked all of the metering plates and the weir. The factory did ask us to check the temps as the refrigerant passes thru all three metering devices and said we should have a 30 degree difference from condenser to evap. But I didn't see any obstructions so I was a little stumped if the temp difference was off what else could cause it besides an obstruction?

[acjourneyman]

I would say one thing for sure is no heat transfer in the evaporator, IE, no flow or tubes are dirty, or are coated on the refrigerant side.

[jayguy]

We cut a section of the evaporator out and replaced the frames and put new eliminators, complete teardown with new bearings, oil pump, vent line solenoid, new CH530 purge, new pressure switches and tang assemblies.

you have done quite a bit of work. i would seriously question the vane assemblies and the staging of the 1st and 3rd stage vanes (esp. since they were damaged and replaced). this is very important to get right. you may be stacking refigerant in the condensor because you are stuffing the refrigerant down the economizer vent lines. you could have a restriction in the refrigerant distribution tray, like you mentioned.

double check that your temp sensor is accurate. then take every pressure and temperature that you can. you should be able to run the chiller at minimum. you mentioned that you can not. is it because you trip too quickly or is it that the chiller tries to load up? you were not quite clear as to why. the clear tube idea was the first thought that entered my head.

let us know.

good luck.

[txhvac]

Good point Jay, if 1st & 3rd stage vanes were rebuilt(hopefully they were) did you stamp them? & put them back exactly where they went (after cleaning)? If the vanes are off, or the seals, impeller to diffuser....to name a few are not mic'd to specs you can have refrigerant blow-by. This can cause adverse effects, ex. load machine up too quickly, loaded starts etc. Measurements should be taken during disassembly & reassembly. Not trying to criticize your work, hope this can help.

[acjourneyman]

Although if the vanes were in the wrong position it would trip the breaker or blow the fuses on start up.

[maxster]

was that a new charge installed after the teadown?

[shelby]

was the original oil logged charge distilled back in

[cateyes]

there may be debris ( gasket material ), blockinhg the orifice plate after start up. it may seem unlikely but i've seen it before... please let us know the outcome.

[pipingpro]

I wanted to list a few answers to questions that were posted:

We didn't replace the vanes, the eliminators sucked into the Suction 90 but never made it into the vanes. We put the newer style vane arms on though.

New refrigerant was put in and the old r-11 was recycled. The machine trips right away as the evap. temp drops VERY quickly.

I don't think its debris in the oriface plates because all of the ones I have done has had the debris laying in or around the oraface, in which we found none.

I also put the newer style labrynth seals and mic'd the shaft. All was within tolerance. The evap temp was taken with 2 different probes and not just the sensor.

Tubes are clean on the inside they were cleaned twice before they were eddy currented.

When we had the shell open the outside of the tubes were clean.

I will post more info tommorrow as far as the temps/pressures.

Thanks

[chiller32]

Stealer country gets real cold at night about this time of year.

[stickerhead]

Are you sure you have water flow thru the evaporator? Have you checked delta P and delta T. I know it is hard with such a quick trip.

[Healey Nut]

I agree with stickerhead are you sure youve got flow is the flow switch working .is the evaporator water box divider plate in place or is it a single pass evaporater.are the divider plate gaskets (if it has them] good

[pipingpro]

Ok chiller heads, I went today to weld the bottom of the economizer and after that was completed the following happened: I told my partner that a friend of mine from my construction days had recommended that we use his sewer camera to look up at the spray tree to see if it was plugged since it was our last area that was not clearly ruled out. So we started to put the economizer on when one of the onsite Maint. personel stated that they just bought a Rigid Micro see snake (this thing costs $250 and everone needs one in their truck!!!!) and we could use it. It has an LCD screen with LED adjustable light with an 3' extention sections. I thought we could try it to see the spray tree and it worked Great! The tree was clear. At this point we had checked flows, delta T & P and everything so we thought lets just look up in the economizer. We knew the oriface flates were clear but what did we have to lose? Looking up in the evaporator line from the economizer we found a large rag. Funny thing is that we use these boxes of rags that are old white t-shirts and the rag was not one of ours. We think that the rag was blocking the Oriface plate but we push-pulled the refrig. and when we pulled it down may have sucked it up in the economizer. Remember from my first post another contractor was hired to tear it down and diagnose it but we won the job to do the rebuild. Feels like sabatoge but who will ever know other than its on a pump and we hope it makes our nightmare go away...........But that camera for $250 bucks beats any hand scope I've ever used and the turd Herders I used to run with love it. You bet I will use one to look in all economizers even though the plates are clean. Oh, and by the way don't put it in any small line we got it hung up in a copper line checking it and the end hung up on a ridge and tore the camera lens off, but we ordered them a new end for only $85.00. Cheap rental rate for fixing this machine.

Thanks guys for racking your brains...........And I found out today that Rover is not our office dog!!!!

[stickerhead]

Well done, have had that before on a CVHB but it also covered the vanes. Looked like it was growing moss! See snakes are cool but I would wash my hands if a turd herder owns it!

[jayguy]

Looking up in the evaporator line from the economizer we found a large rag.

i used one to check the motor winding thermostats one time. stopped all refrigerant cooling flow to the motor and she tripped out right after an overhaul. worked great. of course, i did not mean to do that;)

good luck.

[acjourneyman]

I should have used a rag one time to cover the economizer flange, I dropped the economizer and went to take out a volute bolt and the little bugger slipped and went right down the economizer tube.It took me 3 hours to get it out and now I don't hesitate to cover em up right away.

[USS AIR]

KUDOS PIPE, HOW DO YOU SAVE THE AC WORLD ALL IN ONE EPISODE?
YOUR SERVICE MGR AND CO STOCKHOLDERS HAVE A GREAT "ASS"ET!:eek:

[drivewizard]

KUDOS PIPE, HOW DO YOU SAVE THE AC WORLD ALL IN ONE EPISODE?
YOUR SERVICE MGR AND CO STOCKHOLDERS HAVE A GREAT "ASS"ET!:eek:



Pipingpro, I think your being stalked!!:rolleyes:

[chiller chris]

Check your roll pins on the vain assemble if one is broken then the vains will not work together and can cause refrigerant to stack. Did you replace or clean up the charge ie get the oil out .

[chiller chris]

check your vain roll pins if the roll pin is broken the vains will not move together and could cause this problem also did the charge get changed or cleaned up.

[stickerhead]

Think he already fixed it!

[jemawalton]

Check your roll pins on the vain assemble if one is broken then the vains will not work together and can cause refrigerant to stack. Did you replace or clean up the charge ie get the oil out .

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