View Full Version : Mismatched system
01-04-2006, 08:20 PM
I got ahold of someones screw up today. I have a walk in cooler with a heatcraft evaporator and condenser. The problem is the evaporator is designed for R-22 and the condenser is R-404a. The pressures are running low and wont come up when I add freon, but it does seem to be cooling ok. I wouldnt doubt it if the freon is mixed, and I will recover and start over if the two parts of the unit will actually work together. What I need to know is if the condensing unit is sized right to work with the r22 evap. The compressor already has POE oil, so I dont see a problem there. To be honest, I dont really have a clue how to tell the sizing on refrigeration equipment.
Here's the numbers:
Condenser, Heatcraft M: MOH010x62 S: T96H00592, designed for R404a
Compressor, Copeland M: RS70C1E-PFV-231 S: 96G42903
Evaporator, Heatcraft M: LSC052AJ S: D96B 11359, designed for 12,22,502, TXV is R22
Any help would be appreciated. I want to get this thing right so it doesnt come back to bite me later.
01-04-2006, 10:26 PM
If the incoming air temp to the condenser is <70F then the headmaster should be bypassing some hot gas. Watch the head pressure as you block the incoming airflow to see if it rises. If the sightglass is full and the pressure goes up, you have a bad headmaster. Check out the heatcraft website for info on your equipment. The condenser is rated @ 7130btu @ 110f ambient (average summer temp in Lubbock hee hee) and the evap 5200btu @ 25f. Heatcraft calls the MOH010X62 an extended medium temp. You need a 404a txv in the evap and 404a gas.
01-04-2006, 10:45 PM
Dang. The part about the headmaster is for a different thread. That's what happens when you try to type and watch football at the same time! Hook 'em horns!
01-04-2006, 10:51 PM
Your question should be directed to your local supply house.
01-05-2006, 02:47 AM
Nice to know Hussmann has branch near you-
or is there another co. that installs r22 setup evaps on EVERYTHING?
Starving coil- get rid of the txv-don't just r/r powerhead.
Check w manuf to see how coil shipped - if it has dist tubes and orifice are they sized for 22 or 404A?
I can't trust magic marker/ tags on stuff anymore
(yep got my heart broken once that way....).....
S-cube. How the heck you do anything during that game?
Great game, even for this SC guy. Congrats to V Young as the new no 1 draftpick. doubt the nfl can top this game...
Originally posted by s-cube
If the incoming air temp to the condenser is <70F then the headmaster should be bypassing some hot gas. Watch the head pressure as you block the incoming airflow to see if it rises. If the sightglass is full and the pressure goes up, you have a bad headmaster.
WHATTTTTT? What do you think is supposed to happen to the head pressure when the condenser inlet airflow is blocked??
I am not familiar with that HeatCraft model evaporator. But the ADT and LET models use a different orafice for different flavor refrigerant. Make sure the correct orafice is installed when changing the valve.
01-05-2006, 09:14 AM
No distribution tubes, just one line (1/2 or 5/8) straight from the txv to the coil.
01-05-2006, 12:08 PM
"pressures are running low"
what does that mean, what pressures do you have ?
if R22 should be in 30's
if R404A should be in 40's
by low, is it 5 lbs, 20 lbs or what
RS70 compressor ratings
+20 R-22 7090 btuh
+20 R404A 6720 btuh
01-05-2006, 12:52 PM
Heatcraft shows the capacity for the MOH010X62S at +20 Deg F SST and 95 Deg F ambient as 8640 BTUH. That LSC052AJ evaporator is rated at 520 BTUH/Deg F TD which would work out to a 16.6 Deg TD.......too high in my book.
The "S" in the MOH010X62S model number indicates this was originally fitted with a Beacon II controller. That R22 TEV you have tells me that somebody ripped out the Beacon II setup and installed the wrong valve on an undersized evaporator.
I'd go with a new Bohn ADT090AJ coil and a QE3X4 valve with a #3 cartridge, a KT43SZ element and new R404A juice.
With that combination you should be running suction pressures in the high 50s to low 60s. With what you got you'll be way down in the 40s somewhere with a big loss in capacity to boot. :(
01-05-2006, 05:32 PM
Thanks. I changed the txv this morning along with a new drier, good vacuum and new 404. I was able to get the superheat where it needs to be and it seems to be working ok.
I'm pretty sure the evaporator has been changed. There was another set of holes towards the door and the lineset didnt come down in the back near the evap.
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