McQuay WSC 087 High Subcool And High Suction SH

[Liana]

Dear Friends,
Below is the log readings from McQuay WSC087 microtech II:

EXV
95.60
Con EWT
82.48
Con LWT
92.43
Con W D T
9.95
Eva EWT
64.96
Eva LWT
59.92
Eva W D T
5.04
Eva Ref P
43.23
Con Ref P
123.02
%RLA
96.33
Suction SH is 7F
Discharge SH is 21F
CHW Setpoint is 44F
Evap Saturated Temp 48.00
Evap Approach Temp 11.92

Cond Saturated Temp 99.50
Cond Approach Temp 7.07


I hv tried to adjust the Suct SH and the discharge SH by closing Liq. Injector and turning the expansion valve screw bolt adjuster.
But the result still remain the same.
anybody can help me to guide me in adjusting the condition above?
thanks a bunch for your great help.

Miss Liana

[stickerhead]

How did you get a subcooling reading without a liquid line temp on this log?

[freonrick]

a exv does not have a adjuster screw on it.
did you check all sensors for accurate readings?
both evap and cond approach is too high.
you need to get an exp tech on that machine.

[Liana]

Sorry, the Liq L Temp is 82.4

[787 Guy]

I wouldn't do anything until the Lvg. CHW was down to setpoint

[stickerhead]

So your subcooling is 17 degrees? That is a bunch. Did you use your own instrumentation or the micro? I don't trust the micros. If the subcooling is true, it sounds like you are stacking the condenser with liquid. That is the reason for the high SH and high LCW. What type of metering device does it have, piloted TXV to main valve or EXV? R-134a should have around 15 degree discharge SH at full load with liquid injection turned off

[OzziePedro]

Make sure your flow is correct and check your gas charge. It appears to be at full load but not doing much delta T.