trane cvhf centrifugal chiller sensor calibration

[mc1647]

i have a 2000 ton trane cvhf centrifugal chiller with adaptive controls , i have noticed the what the control is resding is different then the actual

also the mechine shut down on low oil pressure but the dianostic message read oil transducer calibration

where in the controls and how can i calibrate the sensors on this mechine the o&m manuals that came with the chiller are no help . any help would be apreacted

[Edited by mc1647 on 06-30-2006 at 09:56 PM]

[scott123]

If its a UCP2 control, the differential between transducers can not be adjusted. Best thing to do is check the differential between the high/low oil when the chiller is off. I think (can't remember) the max diffential is 2 psid. Above that and the chiller will lock out. I actually had one case where the transducers were fine, but the input on the board was bad and I had to replace the board. Easiest way to determine is swap inputs (when chiller is off) and make sure the readings cary over to the other input. Unually though one of the transducers is the problem.

[chiller mekanik]

Don't overlook the oil filter or the fact that the sensors could be doing what they are suppose to, shut machine down to protect compressor.
Also, what amount of amps does the oil pump pull compared to nameplate & old logs.
I've actually had situations where the pump would "drag" the motor down & the result would be lower pressure & sometimes overamp the pump motor.
I've even had a few where the reason the pump assy was hard to turn was due to copper plating.

[scott123]

When the diagnostic says "differential pressure transducer calibration" the UCP2 is trying to tell you the transducers are not reading equal when the machine is equalized. Any oil pump "drag" on a CVHF chiller will result in a blown fuse. The 6 1/4 amp fuse will blow very easily at the slighest problem with the pump.

[mc1647]

Originally posted by chiller mekanik
Don't overlook the oil filter or the fact that the sensors could be doing what they are suppose to, shut machine down to protect compressor.
Also, what amount of amps does the oil pump pull compared to nameplate & old logs.
I've actually had situations where the pump would "drag" the motor down & the result would be lower pressure & sometimes overamp the pump motor.
I've even had a few where the reason the pump assy was hard to turn was due to copper plating.

i have changed the oil filter after the calibrate transducer dionistic error showed up but i would still like to know how to cailibrate the sensors and transducers on this mechine

[scott123]

YOU CAN NOT CALIBRATE THE TRANDUCERS. You need to read my previous post which explains what to check.

[chiller mekanik]

C'mon Scott, lighten up.
I do not wish to split hairs with you, I guess I don't see my world as black & white as you do yours.
Over the years, (be it good or be it bad) I've gotten in the habbit of keeping my options open.
I've ran into several machines where the oil pump amps have increased over time & still not blow the fuse unless it was a substantial increase.
After going through the original guestion a little more thoroughly I see now that my tangent was getting into a different subject.
Its a little frustrating on here from time to time because sometimes someone will ask a specific question without many other details & its hard to tell if we're trying to help settle a debate, pass a test or solve a real problem.

BTW, can you tell us how to calibrate the transducers?
Just kidding!!!!

[scott123]

Sorry, excuse me for being an ass. I was at the end of a bad day. I'm a field super, and sometimes things kinda pile up.

Sorry

Edit: I'm sure you're right with the oil pump deal :)

[enart9591]

Regarding the temp sensors reading different than actual:
On some of the larger machines the location of the leaving chilled water sensor may have to be relocated further away from the machine. What is happening is similar to swimming in a pond and your feet are cold but your torso is warm. In other words, you have temperature stratification.

[climpro]

mc1647 after youve changed oil filter got diag oil press transducer,set net oil pressure =22psid if transducer see 30psi youll get this diag , u need service bulletin cvhe-sb -32a ask copy SCOTT-123 TRANE

[mc1647]

thanks i will check what you have sugested and see if this solves the problem p.s scott 123 where could i get this sb

[chillerguru]

there is a problem w/ the new style filter/regulator block. a new design is in the works and a service bulletin should be out in a few months factory says replace oil regulator. due to faulty diaphrams

[scott123]

Originally posted by mc1647
thanks i will check what you have sugested and see if this solves the problem p.s scott 123 where could i get this sb

I tried looking up that bul number but nothing came up (product support on-line)

Also, yes they have had reg problems (when haven't they), but an oil sensor "out of cal" is a different issue.

[blockey]

Check your sensor (temperature) connections, make sure they're tight, a loose conn could give you a bad reading.

[cold-n-mode]

I have seen this problem when the discharge oil pressure reads above 30#s when the chiller is in pre-lube,what is your machines high oil pressure reading before the compressor starts?It should read 24 to 26 in the ball park if not back down the regulator, after the compressor comes up to speed and transitions oil pressure should run between 18 and 22 #s net!

[mc1647]

Originally posted by cold-n-mode
I have seen this problem when the discharge oil pressure reads above 30#s when the chiller is in pre-lube,what is your machines high oil pressure reading before the compressor starts?It should read 24 to 26 in the ball park if not back down the regulator, after the compressor comes up to speed and transitions oil pressure should run between 18 and 22 #s net!


i will check that thanks for the advice

[scott123]

Originally posted by mc1647
i have a 2000 ton trane cvhf centrifugal chiller with adaptive controls , i have noticed the what the control is resding is different then the actual

also the mechine shut down on low oil pressure but the dianostic message read oil transducer calibration

where in the controls and how can i calibrate the sensors on this mechine the o&m manuals that came with the chiller are no help . any help would be apreacted

[Edited by mc1647 on 06-30-2006 at 09:56 PM]

OK, lets go through this again. If the pressure reading is different than actual, you need to determine if you have a bad transducer or a bad input. With the chiller off, swap the imputs and see if the transducer that is reading wrong track to the new imput. If it does, you have a bad transducer. If the bad reading stays on the origional input once sensors are swapped, then you have a bad board. If the transducer is causing a calibration fault before the chiller even runs, there is no adjustment to the oil pressure that is going to solve the problem. If I am miss-reading your post then so-be-it, but if I am reading it correctly you are spinning your wheels going off in other directions.