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nova
12-02-2006, 11:02 AM
We've faced some problems with the suction pressures in TS-series at low ambients. When delivering fresh products with setpoint +4C or so and ambient -20C or below unit cools ok (if needed, not likely at -20C ambients, tho) and after reaching setpoint, heats ok but during heat mode suction pressure goes low. Not necessarely to vacuum, but near 0 anyway. This is probably because there’s no engine coolant heat in accumulators anymore so liquid in accumulator is not able to absorb any heat at low ambients. Unit might go to vacuum during heat mode, but most likely it’ll after unit shifts back to cool again. Unit shuts down with code 10 “High discharge pressure/temperature (+low suction pressure after introducing the low pressure cut-out switch (LPCO) on TS units). We’ve measured the suction pressure and it has been the same before and after suction pressure regulator. I think the only way to overcome this problem is disconnect the LPCO for good. We’ve been wondering why LPCO was introduced at the first place as TS series units has been working like a charm even in Finnish climate. We haven’t had any major scroll compressor problems before LPCO, so disconnecting it would probably be the best bet.

Code 10 problems in other countries (applies to Spectrum TS & code 93)?

fridgie37
14-02-2006, 09:48 AM
Hi Nova
I believe the main reason for the LP switch was in the early days of scroll when there were common refrigerant leaks and as we now the scroll's don't like running in a vacuum for too long.
Cheers

Reeferjon
15-02-2006, 06:28 PM
I'd have to agree with that....leaks were prelevent (better now)....I know that at SMC the general synopsys was to request/get an LP switch fitted to protect the scroll....

Latte
15-02-2006, 06:57 PM
Hi Guys,

When i was working for a Large Haulage contractor in east anglia we fitted hundreds of LP switches to the throttling valves on SB's & SMX's.

We had a large number of contaminations due to the units running when no gas in them, what with the cost of a new pot, oil, cleanup filters ect is was far cheaper to do it.

Now, as ive been out of the game too long i assume the TS units are like the old KD's and the condenser fan runs off a belt permenantly. Obviously, it it was an electric motor you could fit a pressure switch too keep it off at low ambients to get the pressures off.

Could you possibly partly cover the condensers during the winter, the units have an HP switch still in circuit in case anything goes wrong. I know its not ideal but possibly its something for TK to look at in the future.

Surely the Vector (I know it's different as its a trailer) as it runs everthing electriclly via the Genny has head pressure control

Regards

Fatboy

nova
23-02-2006, 06:33 PM
I'd have to agree with that....leaks were prelevent (better now)....I know that at SMC the general synopsys was to request/get an LP switch fitted to protect the scroll....

Well, they didn't think about running units at low ambients. I wonder if TK put LPCO to Canadian market or is it just for Europe? Canada has similar winter climate and for sure they should have seen the same problems if having 'improved' TS units.

reefermadness
04-03-2006, 10:21 PM
As far as i know, i doubt it. I don't have the luxury of working on new units very much since i work for an independant, but as far as i know there has never been a low pressure cut out (suction). Once upon a time in the 80's TK used a low pressure safety for oil pressure in the comp, but thats it. TS series is the body job with the scroll ? I have seen one, but never worked on. We run stuff here very very old. There are no laws about oil leaks, emissions anything.
Reefermadness

fridgie37
08-03-2006, 07:41 AM
Gentlemen

Another thing we have done is partily cover condensor in winter months.
Even to the point of covering up to 3/4 of it.

Food for thought?

Mark

nova
18-03-2006, 01:41 PM
As far as i know, i doubt it. I don't have the luxury of working on new units very much since i work for an independant, but as far as i know there has never been a low pressure cut out (suction). Once upon a time in the 80's TK used a low pressure safety for oil pressure in the comp, but thats it. TS series is the body job with the scroll ? I have seen one, but never worked on. We run stuff here very very old. There are no laws about oil leaks, emissions anything.
Reefermadness

Hi reefermadness

IIRC it was 2001 when TK added LPCO to all TS-series units and ever since we've had code 10 problems when having -20C ...-30C. Also code 93 on Spectrum TS'. Things got a bit better after 1562 software (3 restarts after shutdown applies to code 10 too), but it doesn't fix the basic problem.
As you live in Canada and have very cold ambients too you should have faced this problem in big numbers. I'm not sure though if LPCO is used in NAD?


Regards
Nova

NoNickName
18-03-2006, 05:03 PM
The problem is that when compressor stand still, condensing coils are still condensing, so the liquid migrates from liquid receiver back into the condensers.
A liquid solenoid or check valve just after the coils would be the best choice.

nova
18-03-2006, 06:09 PM
Hi NoNickName (<= :D , nice 'nick')

This problem is most likely caused by the fact that evaporating refrigerant during heat mode in accumulator is not getting any heat at low ambients causing very low suction pressure. When unit shifts to cool, suction pressure can go even lower, which results code 10 and unit shutdown. Having fresh products in compartment means unit runs on continuous mode, not on cycle sentry.


Regards
Nova

reefermadness
18-03-2006, 08:35 PM
To be honest with you, I dont' work on body jobs that much, they aren't really all that common. Since traveling here is in great distances, everything generally travels in 53' trailers. I have a feeling that the micro's here are different. Most of the revisions aren't the same either. I think that i might be out of touch with this subject. Get back to me if you have problems with any NWD's of Carrier Eagles!! Haha. Cheers