57
6.2
PRESSURES AT 100⁰F
AMBIENT
The table below shows good pressure readings when measured at set points
35F and 0F and in 100⁰F ambient
temperatures. Higher ambient temperatures can be simulated by covering the condenser coil to produce higher
pressures.
Refrigerant
Type
Suction
Pressure
PSIGG
35 F
Box
Discharge
Pressure
PSIGG
35 F
Box
Suction
Pressure
PSIGG
0 F
Box
Discharge
Pressure
PSIGG
0 F
Box
R-134a
5-12
180-200
0-1
160-175
R-404A
20-27
320-340
12-20
290-310
Example:
You need to measure the superheat and the ambient is only 70 degrees, and the discharge temperature is
stable at 240psig.
Temperature and Pressure are positively related, meaning they rise together.
Since changing the ambient temperature is not an option, increase the pressure on the condenser by
•
Removing condenser cover and/or fan.
•
Use cardboard to restrict airflow through the condenser, until the desired discharge pressure is
reached and is stable.
Section 7 – Parameter Values
7.1 Parameter Issues
The parameter chart can be used for all Zero units with standard Dixell CPUs and Cab Controllers. Determine what your
unit has to follow the chart correctly.
Common Parameter issues
tS – Temperature measurement unit
This parameter must always be set to ‘F’ first before changing temperature parameters if not already. This parameter
will show your temperatures in Farenheit or Celcus.
FuS – Operating modes: CL=cold, C-H=cold/heat, HPU= cold/heat with reverse cycle
Not correctly set to C-H when unit is installed with heat
IS, SS – Min. set point, Max. set point
Minimum and Maximum setpoint are in correctly set
HtP – Input polarity of overload relay
Often not set correctly to allow correct input to overload relay. With this incorrectly set the unit will display a F1t code
when trying to run on electric stand-by.
