Trane RTHD problem

[jose-carvalheir]

I´m having a problem on a rthd trane chiller. This chiller ha had some problems with the electronic expansion valves. It´s got very little working hours,and has ben replaced both exv, first one worked some hours about 100, then happened the same to the second acording to the ploant staff. The second valve was replaced and still the compressor cuts out for low pressure. Since i didn´t replace any of the valves, i reclaimed the refrigerant charge , did vacum on the equipment and charged the amount of refrigerant in the circuit acording to the factory amount. Still did the same thing , The valves say on display that are opening but the refrigerant doesn´t flow to the evaporator. Only goes throu when compressor stops with alarm, saying to low refrigerant tempreture. It then opens 100% filling up the liquid level. then goes to 0%. I restart the machine and the pressure goes down and look at the sightglass and see that the valves don´t open, and liquid level goes down and shuts of compressor. Could anyone help out on this symptom. On this plant there are more 5 unit´s working and all the other are woorking well.

[install monkey]

drier cores choked? liq line solonoid opening fully,inlet gauze on the exv?? have u checked that the head is pulsing open as the display may say opening but is it,was the new valve bodies cooked when brazing into place?

[goshen]

Hi
it would seem you have a blockage somewhere,or a faulty valve ,or a bad cable?bad control card?
try elimenating,i have never had any trouble with these exv's
good luck

[jose-carvalheir]

I didn´t replace these exv. They are not brazed they are screwed in . They are from sporlan. It´s seems to me some kind of blocking . It´s a bit dificult right now to diagnoise it correctly . The guys from Trane also think it´s dificult to burn up this valves, but it´s funny that this equipment was first start by them. At first start it loss comunication with oil line, was replaced buy them.Started working then a couple of days after it stoped with not reconizing the valves .One was replaced started working then loss comunication with liquid level sensor. Replaced . started working then stopped again replaced second valve . Doesn´t work. The biggest problem is it is installed in a Factory in Angola, i came over here because of some chillers from GEA Nonio, to put working and the guys asked if i could put it working. I´ve meauseres cables and everything only thing that i have found wrong is low pressure sensor when pulling down vacum it started reading bably. At normal working pressure it reads 10 psi lower than the manifold i´m using and the gauges on the machine. Maybe a faulty card. Going to try and change the card from another one .Let you know

[jose-carvalheir]

Thanks for your info. Blockage i suspect since i see the valves don´t open in the sight glass. Funny thou they let liquid throu to evaporator after compressor stops in alarm. then they indicate they closed soon as liquid level achives+ 25mm.

[serviceman]

Your question leaves me puzzled! verficado have communication with the TechView? Check the wiring that is not damaged. actalizado have software on the machine. if you can send me or kesterview TechView readings