View Full Version : Waxing in Centrifugal
10-11-2007, 09:41 AM
We are in the middle of a rebuild of a Carrier 125 ton centrifugal chiller and on all of the internal aluminum parts is a waxy build up. It has dripped into the oil sump but does not stick the the steel only the aliminum. It looks just like someone took a candle and dripped wax on the impeller and vanes. No one seems to know what it is from. Any ideas?
10-11-2007, 05:14 PM
What model chiller is it? What kind of oil are you running in it? When was the last oil analysis? What did the analysis tell you?
10-12-2007, 10:01 AM
More than likely suspects to your problem:
1) Machine has been wet
2) Someone is using the wrong oil for the unit
10-12-2007, 06:23 PM
i used to be one of those vz bem's
i sat there and watched all the work being contracted out.
so i joined the fitters/hvac service tech union and haven't looked back since.
in my area that gravy train is gonna end real soon
10-12-2007, 06:36 PM
125 ton centrifugal? I didn't know they made them that small. I learn something new everyday.
10-13-2007, 12:22 AM
It is likely that what you are seeing is Loctite 515 that got in the system. I have seen what you are describing when opening up machines that had that stuff applied liberally to the cases. Have even seen that in oil filters from the same source.
10-13-2007, 01:09 AM
r404a is right... there are 2 schools of thought for 515... 1 is to soap up the oring in the bag and then install it into the grove... this can leave track marks on the case... the other is to lay a bead on the inner grove lay the oring dry and then lay a bead on the outside of the oring and wipe off excess... if you are seeing track marks... that is my guess... but if you have uniform coating that is something all together different...
10-15-2007, 07:54 AM
We did have an oil test and it came back OK. The chiller has had water problems in the past, which was fixed (short time repair) using Lock-tite. The system is now having a jet-dryer installed to help keep the system dry and clean. We are running Carrier chillers (2) with Trane purge units (2) which is working well at this time (cross my fingers). We have had water problems since these units were installed in 1990. Of course they are R-11 machines and were left over units when they installed. We got a deal (before my time) they should have never been installed. They replaced three York units. It sounds like the Lock-tite may be the problem, since the second unit was just rebuilt and Lock-tite was not used on this machine and we had no waxing issues.
10-16-2007, 07:29 PM
I just witnessed first-hand along with another mechanic the change that occurs with 515 when a Ref.charge is introduced. (R-22)
I had just changed both Evaporator Sight glasses(2") and of course had applied a liberal amoutn of 515 as well as AV compound(loctite Stud Locker).
While transferring the refrigerant back into chiller we both observed the formation of a whitish, cotton like substance all around the outer edge of the sight glasses, inside the evaporator, threaded portion. We were both concerned as the spooky looking stuff looked like it was going to homestead the inside of the sight glass.... Fortuneately for us it was washed away upon start-up and it is as we speak .....Looking for a home somewhere....
You used Loctite 515 on threads? I only use the PST, good enough, I only use the 515 on v- band o rings on 19D Carrier chillers, (and a conservative amount).
Also: In my experiences, alot of the later model 19 DK chillers: (the ones without the "table" under the motor, and w/out vane shaft seal oil cups) they seem to take on water, tube rolls inadequate. These machines they were banging out at Syracuse before the change over to the 19/23 XL & 17/19 EX chillers.
As for the Trane Purifier purge units, they are good, alot better than what else is out there. (Redi Purge, Sonic, etc) In fact, Carrier service sells Purifiers to customers who need a new purge!
As for oil for the compressors go with Mobil DTE Heavy/Medium, or the Carrier equivelent.
Carrier recommends using 515 on the v band o rings, because they admitted that some of the machined mating surfaces on these later DK chillers are not all good, so using the 515 on the o rings vs using vacuum grease is recommended to insure against leaks.
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