Mitsubisi problem in pulling down temperature

[teguh]

Hi All,
Does anybody know what s possible cause of pullingdown error( pulling down in frozen mode )?
It's mitsubisi unit w/ R404a.

I ve checked EOS, transducers, pressure ( D/S ) and refrigerant level. All OK.


Thank you
Teguh

[D.D.KORANNE]

Please specify the problem about system , what refrigerant etc.

[teguh]

Hi D D,
The problem is temp pull down to long time. Need 8 hours to reach minus 20' C. Alarm 903 ( pull down error ) appear when PTI ed.

Refrigerant amount is correct.

Tks

[bruisermac]

is it iced up? i bet its a hot load. what is the commodity inside the container? check the evap fans for proper operation. what is the supply sensor reading? if supply is way colder than return your coil is iced up
open the evap panel and check the coil. run it through a defrost and check the amount of water coming out the drain. make sure the drain holes are not plugged.
reset the defrost timer to 6 hours.

[teguh]

Hi Bruisermac,
It s empty unit. The problem was occured during Pre Trip Inspection.
There are look like normal condition. No ice blocked in evap coil, supply temp 4 'C below returm temp, Box insulation is OK, Refrigerant volume is OK, Disch and suction press are OK during run.

I ever have experience like as above but can be solved by refit evap sensor position.

Thank

[bruisermac]

your coil TD should be greater than 4'c. it should be in the 7-10'c area. u may need to see what position that the EEV is in.heres a tip... u can open it to 100% open by using the controller test mode. when the display reads 100 open disconnect the EEV wire harness. this will keep the valve at full open and may indicate a problem. this way you can eliminate the problem...those EEV are very sensitive and i have replaced alot due to foreign material being trapped in the valve.

[Gary]

"OK" doesn't tell us anything.

If you want help, tell us the temperatures and pressures.

[bruisermac]

glad 2 c ole gary finally making his way to the "red headed step child" part of the industry!! hahaha...i know we all can learn a thing from you dude. i have read many of ur posts in the past and have been impressed.

[Gary]

Nahhh... the red headed stepchild is ammonia... lol

And thank you for the kind words... I try to help out where I can... while I still can.