Trane Screw Question

[IGBTech]

We've got a small RTHB130 chiller with loading/unloading problems (overshoots the setpoint). Replaced solenoids, changed PID, good flows, good charge. Holds dishcharge superheat nicely but when we manual the slide valve to hold, it loads on its own. Has anyone opened these screws? If so is there any literature on them beyond the operations/maintenence manual? I heard trane doesn't want anyone in these compressors. Ran through Talon disks and found nadda.

[supertek65]

it seems as if you have a bad loading solenoid.
can you valve off the oil line from the oil filter to the loading solenoid valve?which I think is 4l2.
sou should be able to check with a gauge.
more than likely you have something in the solenoid or have fowled it.
when did you change oil filter last?
Frank

[IGBTech]

The oil filter was changed last year at end of season by another tech w/our company. We replaced both solenoids even though the old ones looked fine. I tried placing the slide in "hold" and valved of the oil supply line breifly to see if load solenoid was bleeding by but it still loaded up. I didn't close the valve for very long though thinking that that line also lubricates the rotors (is that correct). I could unload the machine manually (with the ucp) but it just won't hold. Is there anything other than the load sol. that could be the culpret?

[txhvac]

Sounds like you have a leaking slide valve, if it will constantly load up- even if when you put the thing in the HOLD position. You have replaced both solenoids, the slide valve is not sticking, that pretty much the only thing left. The slide valve is field repairable. Let me re-explain, it is not the actual slide valve over the rotors, it is the piston which is attached to & drives the slide. The piston has a metal gasket around it, which can wear out, or it can also bind up, but in your case leaking by. The piston rides in a cavity area inside the oil seporater. While your at it, change the oil filter, they should be changed annually. What did you change the PID loop parameters to? Hope this helps.

[IGBTech]

Thanks for the info guys! Any idea where I can find the part number? No hurry, it's supposed to be 114 next week and getting hotter. It's on a hospital emergency room and the customer is probably not going to let us have it until fall (unless the UPC cant unload it fast enought to keep it off of overcurrent). The identical chiller next to it has setpoints of LWT Int-0.025% and LWT Prop-7.2%. We tried LWT Prop from 2.0%-50.0% (1-2% @ a time) and LWT Int 0.020%-0.075% nothing worked right
The equipment is under a full service contract so we'll get 'er done as soon as they let us have it.

[supertek65]

I know that you are in a hurry.
save yourself a lot of time and money.
e-mail and or call Steve grace in lacrosse before you do anything.
I think he is stevegrace@trane.com
for one, you need to make/weld a lifting eye for proper lifting when you disassemble the compressor.
Steve is a great guy and will get you part # and literature.
Frank

[IGBTech]

Thanks Frank! I'll be sure to give him a shout.

[supertek65]

I think the phone number is 608-787-3232

[acjourneyman]

The brass fitting inside the oil seperator is cracked or the flare has split.Pull the seperator and replace the fitting and you will be good to go.These machines have a lifting eye on them already so you don't have to worry about it.

[Knobber]

I think it is probably the brass fitting as "acjourneyman" mentioned. I have seen this happen first hand. I have some pictures we took when we did this repair if you are interested. Send me an e-mail at rjhumbert at msn.com if you want them.

[txhvac]

Yes, I would agree the fitting or the oil seperator could also be an issue. None the less, to get a good visual the housing will have to come off to see.

[19 D Guy]

Just finished up on a job yesterday on a RTHB with the same problem. The slide valve shaft rides in a groove and has a little notch on the end of it. If you open up the compressor measure amount of play you have in the shaft up and down and side to side. Trane in Pueblo WILL NOT TELL YOU ANY SPECIFICS. They will barely give you a yes and no answer. But they do have a Trane rep that could help if you have a P.O. What I was able to ask and they answered for me was if the tolerance on the slide valve shaft should be measured with a dial indicator and not a tape measure. My customer opted for replacement of the compressor assembly rather than going any further in the machine.

[IGBTech]

Thanks again for all the replies guys. Talked to the customer today, he says can't have it till late sept. (oh well his machine). I've got more questions to post so I look forward to your replies.

[IGBTech]

Well everyone, after a very comfotable fall (temperature wise ), we got our mits on this screw. Low and behold, the brass fitting was cracked on the MPT end.
Frank, I haven't called Steve yet. Maybe I'll try him after christmas or at least let the powers to be know of the option. Trane won't sell us anything inside the comp. They also told us we are we required to use our local dealer who doesn't really like us very much (go figure)
Can anyone tell me if the first "seal" (the larger of the two) is supposed to have a gap in it between its end? If it is, it looks like it is good shape. We would like to replace it, since we are in there. If we can't purchase a new one from Trane then we have no choice but to reinstall it.
One other thing, when we opened the machine we found the second pass of the oil seperator had broken loose and made its way down to the end. Has anyone had this happen?
Thaks again to everone for the info.

[chiller mekanik]

Send me an e-mail Brother & I'll give you the info on where to get parts & support.

[chiller chris]

sounds like you have a leak inside comp you need to remove oil seperator rering the slide valve and look for a crack in the oil line i have seen this on many ocations

[low pressure guy]

I Had Same Problem . After Very Long Time Of Talking To Factory And Sale Rep . I Recovered Charge And Removed Oil Charge . Found Oil Over Charged From Factory . Oil Was Insulating Sensor . Making Controls To Respond Slowly .