Trane RTAD100

[frank]

Just taken over the maintenance of this 2 circuit chiller.

After de-gassing and fixing the leaks on the oil separator heater pockets, renewing the recovered oil and recharging, the machine runs, loads, unloads and cools OK.

However, on shutdown, both circuits alarm on 'oil return problem'.

Looking through the manual,there are 2 levels of oil protection..the internal level switch and the calculated condition

Oil failure protection
The logic of the UCM uses a comparison of the entering oil temperature at the compressor, to the saturated-condenser temperature, to determine if there is an oil line restriction.The differential between the entering oil and the saturated-condenser temperatures is referred to as the “oil loss differential setpoint“ in the service settings menu.
If the entering oil temperature drops 2°C below the saturated-condenser temperature for more than 30 minutes, the circuit will shut down on a CMR diagnostic.

I had the machine running continuously for over 30 minutes at 1 stage and monitored condenser saturated temp and oil return temps which have been within 2K on CT1 so no shut down error, but as soon as I stop the machine/circuit, it alarms.

Circuit 1 oil and condenser sat temps were within 2K but still alarmed on shutdown. CT2 temps were identical but still alarmed.

Oil leaving temp was 50.2C CT1, 53.2C CT2 and returning was 35.6C CT1 and 38.6 CT2.. Sat Condensing temp was 37.6 CT1 and 38.6 CT2.

The manual refers to the oil differential temp setting in Service level 2 but I can't find it.

There is something else strange with the controller. The machine is a 2003 model so it is just 10 years old. In all that time, it only records 21 compressor starts for both CT1 and CT2, and I've added about 10 starts today. Compressor running hours are 93223 hours for CT1 and 93221 for CT2. In 10 years, the maximum hours they could each have run is 87360, providing they ran 24/7/52/10 :-)

Pressing the controller buttons today, looking at sensor readings etc, and the controller has re-booted it'self a few times, so I'm leaning towards a dodgy Adaptive controller?

Any thoughts anyone?

[install monkey]

http://www.mediafire.com/download/ht...ne_chiller.pdf
http://www.mediafire.com/download/ca...m_controls.pdf

oil filter due for change?? oil solonoid valve not opening- check the oil level in the seperators- fit gauge on hi side,underneath the seperator and use ur sight glass to see oil level in each seperator

[passandscore]

I had a similar issue years ago and it ended up being a faulty oil temp sensor although it seemed to be working fine when i monitored operation.

[frank]

I had a similar issue years ago and it ended up being a faulty oil temp sensor although it seemed to be working fine when i monitored operation.

Was that on both compressors?

[frank]

http://www.mediafire.com/download/ht...ne_chiller.pdf
http://www.mediafire.com/download/ca...m_controls.pdf

oil filter due for change?? oil solonoid valve not opening- check the oil level in the seperators- fit gauge on hi side,underneath the seperator and use ur sight glass to see oil level in each seperator

No SG in separators I'm afraid.

[install monkey]

U use ur manifold as a sight glass and move ur gauges up to determine oil level

[FreezerGeezer]

Or a bit of clear hydraulic hose with fridge fittings. Saves messing about with the SG.
Alternatively we found you could guage the oil level accurately enough by leaving the circuit off for a while, then running an IR thermometer up the separator. You see quite a distinct temp. change at the top of the oil.
Sorry it's too long since I worked on these to remember anything more useful, other than check the sensors carefully. Mind you, since the comtroller's playing up it could well be that.
Service Level 2 is probably the Trane only section, for setting up the factory parameters.
If it's an UCM/CLD there are test points on the main card(s). Top left corner iirc. Put your meter on them & if you don't have the voltage indicated (printed by the test points) the board should probably be changed.

I agree that the starts:hours don't look right, unless it's a 24/7 process chiller. Even then I'd be astonished to see a ratio like that. And as you say, for a 2003 machine it can't be old enough to have those hours in the first place.
It's probably worth a call to Trane B'ham to talk to their tech. support bloke. If it's still my old pal Pete he's pretty helpful. Just make sure you always have the whole model & serial no. when you call. Yes, all those numbers & letters do mean something & can help a lot.

[frank]

U use ur manifold as a sight glass and move ur gauges up to determine oil level

Not possible.....the schraeder is on the top of the separator

[serviceman]

if I remember RTAD machines are machines with R-134a, please check the oil level in the oil separator produces excess oil problems in this type of machine

[serviceman]

There are two ports on the one where you drain separator and schraeder oil on top of the separator, is used to measure the oil level

[install monkey]

told ya frank! haha- gotta get on all 4's to look under control panel- supp plenty of bg sips and u will see it when ur sozzled!!!


QUOTE=serviceman;283091]There are two ports on the one where you drain separator and schraeder oil on top of the separator, is used to measure the oil level[/QUOTE]

[passandscore]

Was that on both compressors?

The faulty sensor was on one compressor.

[RusBuka]

Frank you have Oil rotolock at bottom of separator.

[frank]

What do you think of the possibility that the fault occurs because the reference differential is missing from the controller?

The manual says that the oil differential setting is in level 2 Service settings, but I can't see it as it's not there.

As the compressor stops, a calculation is carried out of the condenser saturated temperature v oil return temperature. Without a reference, the calculation fails so the machine faults. We already know that the controller has issues.

I'm not convinced that there is an oil flow problem as the oil float switch is quite happy when the machine is running and the oil return temp is within 2K of the cond sat temp at all times.

[FreezerGeezer]

I reckon you're likely right on where the fault lies.
However, as per my post above, the parameter you want is not in the second level, it's in the third. The Trane-only, Chiller Configuration section, according to the manual IM posted above.
Do you have the Service Bulletin for commissioning the chiller? That'll give you the ranges & factory settings on everything.

[frank]

Hi Geezer
Ive got access to the level 3 service settings but the oil differential setting is not in there which makes me think the problem is controller based

[passandscore]

I would have to agree. If you are missing parameters completely even thou you have access to all levels and the controller itself resets sporadically I would consider replacing the controller. Perhaps Trane has some technical engineers that can help you confirm this. We would hate to be wrong!

[install monkey]

rang trane once regarding a techie issue- miserable gits wouldnt tell me anything, but were more than happy to send me a chimp for £500 a day!

I would have to agree. If you are missing parameters completely even thou you have access to all levels and the controller itself resets sporadically I would consider replacing the controller. Perhaps Trane has some technical engineers that can help you confirm this. We would hate to be wrong!

[FreezerGeezer]

Yup, that's what I used to do! It's not like split OEM's, that's for sure. But then, with chillers it tends to be a lot more expensive if the bloke on site makes a mistake...
Like the time a brand new RTAC got frozen because the site bloke kept resetting the anti freeze alarm.

The trouble is, unless you know the person on the phone, you have no real idea if they're competent. You wouldn't believe how many people ring with absolutely no information, haven't even taken a look at things themselves, and expect you to magically diagnose it for them!
Then there's the co. policy of not releasing pass codes.
Or if you do get a pass code, not all the controllers are clear language. So you need the manual to explain what everything is. SMM's & the CH532 (iirc) are the prime examples.

The worst ones were where we couldn't help at all because we didn't have the required information. Spares, for e. g, tended not to put any fitting instructions with any parts. Even superseded parts. Nor had they provided us with the information!

[frank]

Update.

I was right in diagnosing that the machine failed on compressor shut down because the Oil Differential calculation could not be carried out as the setting did not appear in the Level 3 configuration menu.

Apparently, there are 2 types of compressors that are fitted to the RTAD100 and you select the correct model in Level 3. The compressor selected in my case was the incorrect one, so the Oil Differential setting did not appear. Once the compressor setting was corrected, the Oil Differential Setting appeared, and on shut down, the calculation was carried out and the machine was 'happy'.......so am I

The other type of compressor has an oil differential switch fitted externally.

Just a pity it doesn't mention this in the manual...it would have saved a lot of head scratching and a wad of money for the customer

Confirms the old saying of learning something new every day.