Trane Air Cooled Chiller

[iceman007]

Hi,

Does anyone have access to a Trane service manual ?

Twin Helirotor compressors. Lead compressor tripping (every few days) on high oil temeperature. Ran the machine today for most of the day and no problems have reoccurred, exept an alarm for the condenser fan variable speed drive. Setpoint for entering water temp was set at 6 degrees C, thought this was too low as a few evaporator temp trips had been happening so increased to 9 degrees (no glycol in water) and the oil temp seemed to stabilise at about 70 degrees C.

Even better if anyone else has come across this and has an idea. Using R134a refrigerant.

Thanks

[NoNickName]

High oil temp (are those compressors from J&E Hall?) is probably caused by excessive superheat, but also to low evaporating temperature.
Entering water temperature setpoint for HVAC application should be set to 12°C, definitely not to 6°C.

[iceman007]

Badged as Trane compressors but probably manufactured under licence. I had at first thought that either part load conditions or undercharge may be the problem (not enough suction gas cooling motor). Anyway, reset setpoint up on water, and will have to see what happens. I did have a similar problem once and it was all because of a failing suction temperature sensor.

[NoNickName]

Oh, yes, part load also causes high discharge temperature

[iceman007]

Oh, yes, part load also causes high discharge temperature


There must be a way to deal with it, other than liquid injection, or similar. methods such as using another circuit with a TEV.

[Lowrider]

What type of unit is it?

Normal oil temperature is a few degrees above condensation temperature, not 70 dgrC

[Lowrider]

Also please give me suction temp, discharge temp, liquid temp. entering and leaving water and entering and leaving air, RLA, oil temp and suction and discharge pressure both from display as well as gauge!

[iceman007]

What type of unit is it?

Normal oil temperature is a few degrees above condensation temperature, not 70 dgrC

RTAP200LN.

I expect usually oil temp to be around 50 degrees. I believe the low setpoint of 6 degrees entering evaporator is the cause of it.

R134a suction 3.4 bar, discarge 8.5 bar (part load conditions) compressor current approx 50% rated.

[Lowrider]

You probbably mean RTAB200!

Trane chillers work on leaving water, not entering!

Suction around setpoint should be around 2 bar!

You should have a UCM-LCD controller, please check and see if pressures in UCM are almost the same as gauge-pressure!

If you can provide me with the other data i'll know more!

Partial load shouldn't matter since it has an electronic expansion valve and UCM will try and keep superheat at 3,5K

[Lowrider]

I did have a similar problem once and it was all because of a failing suction temperature sensor.

And did you fix it yourself?

[iceman007]

You probbably mean RTAB200!

Trane chillers work on leaving water, not entering!

Suction around setpoint should be around 2 bar!

You should have a UCM-LCD controller, please check and see if pressures in UCM are almost the same as gauge-pressure!

If you can provide me with the other data i'll know more!

Partial load shouldn't matter since it has an electronic expansion valve and UCM will try and keep superheat at 3,5K


No I mean RTAP200.
This is only an only an intermittent fault not one that occurs more than every few weeks.
Anyhow, I have rescheduled a return visit to check for any reoccurrence, which I don't expect, as this oil fault was always occuring with a low evaporator temperature fault. The setpoint is on entering water temperature and not leaving water temperature. It is the entering water setpoint that is the value that the chiller controls. It was set at 6 degrees C, and was running with an entering water temp of 6.3 and a leaving temp of 5.3 degrees.
Thanks for all input.

[iceman007]

And did you fix it yourself?

???? Thats a strange question.

[Lowrider]

Are you sure about the setpoint! Please let me know!

Checked the trane site and there is no RTAP!

[Lowrider]

???? Thats a strange question.

Why do you think this is a strange question?

[iceman007]

Why do you think this is a strange question?

Never been asked before a question like that.

It is a RTAP 200 LN, manufactured in 2003.
The setpoint I am definite about.

[Lowrider]

I'll be honest, I work at Trane and never heard off an RTAP! All our chillers work on leaving water, except for a few smal scroll chillers!

If a suction temp sensor is changed, the saturated evaporator sensor also needs to be changed since they are a pair!! That's why I asked!

Let me know what you saw!

[Lowrider]

An aircooled screw chiller from Trane has an oilcooler at the top on each site of the condensor. Oil from the separator will go through the condensor into the screwcompressor. Here's the oil temp sensor. The sensor should be 10k ohm at 25dgrC.

Possible the sensor is defect, check with 50k ohm meter, or the ucm is at fault. This can be checked by placing a 10K ohm resistance after removing the sensor wires on the ucm. if it's off by more than 2 dgr above or belowe, replace the board on which the sensor is connected!

[iceman007]

I'll be honoust, I work at Trane and never heard off an RTAP! All our chillers work on leaving water, except for a few smal scroll chillers!

If a suction temp sensor is changed, the saturated evaporator sensor also needs to be changed since they are a pair!! That's why I asked!

Let me know what you saw!

In a few days I'll drop a reply on this thread with the final ins and outs. On the controller you can only change the eb=netring setpoint.

As to the other question, I couldn't tell you what happened after my visit, as it was passed to the guys that did the installation.

[giovanni]

US Iceman, I was on the Trane website and did notice a RTAA air cooled, helio compressor section, with literature. use this link and click on product literature
http://trane.com/Commercial/

Hope this is what your lookiing for

[wkd]

In your post you mentioned the condenser variable speed drive fault.Since the oil is cooled via the condenser air flow maybe at low ambient temps there is not enough cooling for the oil made worse if the drive is playing up.Have seen this on York chillers at low load.

[Lowrider]

Did you visit the site yet and if so, what did you find?

[FreezerGeezer]

Well, Sanderh is right - there's no such thing as a RTAP.

It may be a RTAD? Sometimes the name plates aren't too clear. Or is it a rental chiller? They may have a different model no.

[Lowrider]

RTAD is possible!

A RTAD has a lcd touchscreen, techview. The RTAC has the UCM-CLD.

If it's a rental than they must have renamed it. In the Trane datbase there's no RTAP.

I think a RTAD would be more logical!

[FreezerGeezer]

Sander, it's the other way around. ;)

RTAD = UCM-CLD

RTAC = CH530 (Techview)

I reckon our chap has a RTAD 200 LN (SE or HE??)

[Lowrider]

Well you're right and you're not! They've both been produced with techview and ucm! But the new RTAD's, at least in Holland, come with Techview. RTWB's still come with UCM-CLD! RTUC's and RTHC also both and RTHD's with techview!

The LN is Low Noise. SE is standard efficiency, HE is High Efficiency. I'll need the serialnumber and manufacturing code and if possible the complete modelcode to tell what's in it (tonnage, compressors, fan's, condensor etc!)

[FreezerGeezer]

I've yet to see an RTAD over here with a Ch530?? I guess I'll have to go check. Wouldn't like to assume anything where Epinal are concerned! ;)

As far as I know any C series rotary chiller has a CH530 (Techview for anyone who hasn't heard of a CH530), as well as most of the current scroll based chillers (the CGAN's have the CH532).

[Lowrider]

We even have CGWN's with CH530.

At the moment we are building 6 cooling/heating centres complete with BAS (Tracer Summit) ranging from 8MW to 26MW.

Also a lot of coolcentres with multiple RTWB's and Chiller plant manager!