ref'd van txv

[thinktwice]

Hi,
im repairing a ref'd container van(mitsubishi, quite old). I cannot get the right temperature, it only arrives at -16C/3.2F ( 8psiLS/200psiHS ) . I suspect txv is not working properly. The design data is 15,300btu @ 0 F & 100F ambient temp., no data on the txv, can anyone help on this?! :)

The reason why I open the system is, the supply voltage phasing reversed, the condenser fan turns on reverse direction, condenser high pressure and relief valve discharge all the refrigerant (R134a)

[Brian_UK]

We need some system readings to be able to comment fairly.

Also, what is the container insulation like?

[Magoo]

Possibly if rotation was changed, [ hopefully a multi-directional oil pump in compressor ] that valve damage has occurred and compressor is not operating to specification. High discharge pressure/temperature. Check compressor head temperature, versus the SDT.

[thinktwice]

thanks for the reply...

brian: its polyeurethane insulated. at 3.2F low side pressure is 8psi and high side pressure of 200psi, when I get suction pipe temperature is 92F, super heat really high.

magoo: ill check if the compressor oil pemp is multi directional, and also head pressure also

[bruisermac]

why do you think the txv is the problem? if u blew out the charge cause of high pressure due to the condenser fan is running backwards then isnt that ur problem? im not sure i understand your question.

is it a CPE10 MHI unit? those had 3 condenser fans which will draw air from below the coil. if its newer like a CPE14,15 it will have a single condenser fan.

to change rotation of the fans switch 2 legs on the contactor if the phase selection contactors are no good.

on the CPE10 the txv pulls apart and you can clean it out if crap gets in there...

[bruisermac]

what does ur sightglass look like? bubbles?

[thinktwice]

brueisermac:

thanks for the reply, sorry for the delay reply co'z I gather all the details even the history of that ref'd van. I found out that the TXV installed is already replaced by another TXV, since the original gas used was R12 and they retrofit the system into R134a system, it only have one fan, no bubbles inside liquid sight glass. the funny thing I discover when I strip some of the paint is, this container van was originaly "THERMO KING" CFTI M 32 model. It take too long to cool down and it only reaches -16C considering the unit is running overnight.

[bruisermac]

i think you should check the quality and charge of refrigerant that you have. did you fix the leak at the pressure relief valve? you may still have a funky situation. check the drier for temp difference across it. it should feel warm. also are the fans working properly? the condenser fan rotates counter clockwise while you are standing in front of the unit.
you may have a faulty throttling valve as its designed to maintain a preset suction pressure...but i cant remember the settings off hand.

i would check the txv inlet strainer cause u never know what the last guy did to it...good luck and keep us posted.

[JOEYMORAN]

encountered same problem way back.unit was tk-cf11.i did all the procedure you did but failed.until we replaced the container box itself,then bingo.i used to work on leased container van in our country bfore

[thinktwice]

What a long checking, thanks for all your reply guys, i really appretiate it,
BRUISERMAC: i check all the necessary parameters that you mention and I think its normal, thanks for the checklist bro.
After all the queris and testing I done, I observe the unit overnight and discover what gives me the touble. ITS THE BOX IT SELF! You cant really noticed this trouble during sunny days but at night, bingo it appeared.
And JOEYMORAN was right, thanks bro.

Additional info, as gathered, insulation of this container van is only efficient up to max of 10years (or less depending on the climate condition where it is located) after it, insulation is fully saturated by water.

[bruisermac]

sweet glad u figured it out...thanks fo rthe update on the repair. its great to know if the info paid off and in this case it did...joey knows his sh!t

[thinktwice]

yup.....thanks again guys!