Fieldpiece SMAN2 - 3-Port Digital Manifold - Manual (Page 2)

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What is Superheat and Subcooling?
Why Do I Need to Measure It?
Superheat is the difference between the
actual temperature of the refrigerant (gas) as
it leaves the evaporator and the boiling point
of the refrigerant. After boiling, the refrigerant
continues to heat up. The number of degrees it
“heats up” after boiling is called the superheat.
Under worst case conditions (low load for fixed
orifice systems), the refrigerant in the evaporator
boils off near the end of the evaporator coil. To
make sure liquid doesn’t enter the compressor
under the worst case condition (low load),
the refrigerator or A/C manufacturers publish
charts indicating what the superheat should be
at a given indoor wet bulb measurement and
outdoor air temperature.
Measuring superheat is your best indication
on a fixed orifice system of the proper
refrigerant charge and operating conditions.
If everything else is working properly and the
actual superheat is too high, add refrigerant. If
it’s too low, evacuate refrigerant.
Subcooling is the difference between the
boiling point of the refrigerant in the condenser
and the actual temperature of the refrigerant
as it leaves the condenser. The degrees that the
refrigerant “cools down” below the boiling point
is the subcooling. Under worst case scenario
(low load for TXV) the subcooling will continue
to rise. If the subcooling rises too high, liquid
may be backed into the compressor causing
damage and catastrophic failure. See www.
fieldpiece.com for more technical articles.
Location of Subcooling Test
Location of Superheat Test
Specifications
Display size: 5 inches (diagonal)
Backlight: Blue (On for 1 minute unless turned off manually)
Battery: 6 x AA (Battery life below based on alkaline type)
Battery life (SMAN2): Approx. 500 hours (without backlight)
Battery life (SMAN3): Approx. 135 hours (without backlight)
Low battery indication: is displayed when the battery
voltage drops below the operating level
Auto Shut off: 30 minutes of inactivity when APO is activated
Operating environment: 32°F to 122°F (0°C to 50°C) at <75%
relative humidity
Storage temperature: -4°F to 140°F (-20°C to 60°C), 0 to 80% RH
(with battery removed)
Temperature coefficient: 0.1 x (specified accuracy) per °C (0°C to
18°C, 28°C to 50°C), per 0.6°F (32°F to 64°F, 82°F to 122°F)
Over range: "OL" or "-OL" is displayed
Weight: 3.05 lbs (1.38 kg)
Pressure
Connector Type: Standard 1/4 NPT male flare fitting
Range: 29” HgV to 580 Psig (English), 74 cmHgV to 0 to 4000KPa
(Metric)
Resolution: 0.1 psi/inHg; 1 kPa/cmHg
Accuracy: 29” HgV to 0” HgV: ±0.2” HgV
74 cmHgV to 0 cmHgV: ±1 cmHgV
0 to 200 Psig: ±1 Psi; 0 to 1378 KPa: ±7 KPa; 0 to 1.378MPa:
±0.007MPa; 0 to 13.78 bar ±0.07 bar
200 to 580 Psig: ±0.3%+1 Psi; 1378 to 4000KPa: ±0.3%+7 Kpa;
1.378 to 4.000MPa: ±0.3%+0.007MPa; 13.78 to 40.00bar:
±0.3%+0.07bar
Maximum overload pressure: 800 psig
Units: Psig, kPa, MPa, bar, inHg, and cmHg
Microns for Vacuum (SMAN3 only)
Connector Type: Standard 1/4 NPT male flare fitting
Range: 50 to 9999 microns of mercury
Resolution: 1 micron (50 to 2000 microns), 250 microns (2001 to
5000 microns), 500 microns (5001 to 8000 microns), 1000 microns
(8001 to 9999 microns)
Accuracy: ±10% or ±10 microns, whichever is greater (50 to 1000
microns)
Maximum Overload pressure: 500 psig
Units: Microns of mercury
Temperature
Sensor type: K-Type thermocouple
Range: -95°F to 999.9°F (-70°C to 537.0°C)
Resolution: 0.1°F/°C
Accuracy: ±(1.0°F) -95°F to 199.9°F; ±(0.5°C) -70°C to 93°C
±(2.0°F) 200°F to 999.9°F; ±(1.0°C) 93°C to 537.0°C
Note: All accuracies are after a field calibration.
Refrigerants
The P-T charts of the following refrigerants come pre-programmed
into your SMAN. In your SMAN the refrigerants are listed in order of
most commonly used. Here, they are listed in numerical order for easy
reference.
R11, R113, R114, R12, R123, R1234YF, R124, R125, R13, R134A, R22,
R23, R401A(MP39), R401B, R402A, R402B, R404A, R406A, R407A,
R407C, R407F, R408A, R409A, R410A, R414B (Hotshot), R416A, R417A,
R417C (HOT SHOT 2), R420A, R421A, R421B, R422A, R422B(NU22B),
R422C(Oneshot), R422D, R424A, R427A, R434A(RS-45), R438A(MO99),
R500, R502, R503, R507A, R508B (Suva95)
Maintenance
Clean the exterior with a dry cloth. Do not
use liquid.
Battery Replacement
The battery must be replaced when the
battery life indicator is empty. Turn your
SMAN off and replace with 6 AA batteries.
Cleaning the Sensors (SMAN3)
Over time, the vacuum sensor of the SMAN3
may become contaminated with dirt, oil, and
other contaminents introduced from pulling
vacuums.
1 Never use an object such as a cotton swab to clean the sensor,
you may cause damage to the sensor.
2 Open all knobs/valves, and cap all the ports except for the center
port.
3 Drop enough Isopropyl (rubbing) alcohol into the uncapped
port using an eye dropper or funnel so that it can flush out
contaminents.
4 Cap central port and gently shake your SMAN upside down to
clean sensor.
5 Turn right side up. Open a port to pour out the rubbing alcohol
and open all ports to allow sensors to dry out; usually an hour or
so.
Calibration
Temperature
To calibrate your SMAN temperature
thermocouples, adjust the pot on the front of
the meter labeled T1 Cal or T2 Cal. The best way
to calibrate is to match to a known temperature.
Ice water is very close to 32°F and is readily
available. Accuracies of one degree or better
are easily obtained.
1 Stabilize a large cup of ice water by stirring. Pure, distilled water
will be the most accurate.
2 Press the circular button until your SMAN enters Direct
Temperature (T1 T2) mode.
3 Immerse the temp probe in ice water from T1 and adjust the
T1 Cal pot with a flathead screwdriver and let it stabilize, keep
stirring.
4 Repeat Step 3 for temp probe in T2.
Pressure Zeroing
To calibrate your SMAN pressure sensors to
atmospheric pressure, ensure that your SMAN
is disconnected from any pressure source and
at equilibrium with the ambient pressure.
1 SMAN must be in Superheat/Subcooling, Saturation, or T1 T2
Direct mode.
2 Press the CAL Atmospheric Pressure button and your SMAN will
set the zero point of pressure to the ambient pressure.
Advanced Pressure Calibration
Your SMAN has the ability to perform a linear
adjustment of the pressure sensors based on
refrigerant type, temperature, and pressure.
Calibration setup: For best results, perform both the Temperature
and Pressure Zeroing procedures. See Calibration section for
details. This will ensure pressure readings are zeroed and
thermocouple is properly calibrated to the T1 port of the SMAN.
Calibration to T2 port is not necessary for this calibration.
The refrigerant cylinder should be stored in a stable ambient
environment for at least 24 hours before calibration.
1 Press circular button until your SMAN enters T1 T2 Direct mode.
2 Plug in a K-type thermocouple into T1. (A bead type
thermocouple, like the ATB1, is recommended.)
3 Connect the SMAN to a refrigerant cylinder of a known, single
refrigerant using an EPA approved service hose. Be sure to open
both HIGH and LOW side valves on your manifold and cap the
unused ports. (If caps are not available you can connect both ends
of a refrigerant hose to the two unused caps. Note you will lose
some refrigerant into the hose using this method.)
4 Press the REFRIGERANT button to match the refrigerant of the
cylinder you are using.
5 Attach bead-type thermocouple to the side of the cylinder using
tape. It is recommended to attach in the middle of the cylinder.
Important: Let the temperature of the thermocouple stabilize to
the refrigerant temperature for 1 to 2 minutes or until stable.
6 Open the refrigerant cylinder. The pressure inside cylinder should
now be displayed on both HIGH and LOW side pressure sensors.
7 Press the CAL Test Pressure button. If successful, "Good" will
display for 3 seconds. If failed, "Err" will display for same time.
Your SMAN checks with its built-in P-T charts to compare the
temperature of the refrigerant in the tank to the vapor saturation
temperature based on the refrigerant you selected. If the measured
pressures on your SMAN are within ±3psi of the P-T chart pressure
corresponding to the vapor saturation temperature, the SMAN will
adjust the pressure sensor linearity to match the P-T chart.
Possible causes of failed "Err" pressure calibration:
1. Refrigerant tank was not stored in stable ambient conditions for at
least 24 hours.
2. Thermocouple attached to refrigerant tank was not properly
calibrated to T1 port of SMAN.
3. Thermocouple was plugged into wrong port T2 instead of T1.
4. Incorrect refrigerant was selected on the SMAN.
Limited Warranty
This meter is warranted against defects in
material or workmanship for one year from
date of purchase. Fieldpiece will replace or
repair the defective unit, at its option, subject
to verification of the defect.
This warranty does not apply to defects
resulting from abuse, neglect, accident,
unauthorized repair, alteration, or unreasonable
use of the instrument.
Any implied warranties arising from the sale of
a Fieldpiece product, including but not limited
to implied warranties of merchantability and
fitness for a particular purpose, are limited to
the above. Fieldpiece shall not be liable for loss
of use of the instrument or other incidental or
consequential damages, expenses, or economic
loss, or for any claim of such damage, expenses,
or economic loss.
State laws vary. The above limitations or
exclusions may not apply to you.
Obtaining Service
Call Fieldpiece Instruments for current costs
on our fixed price warranty service. Send
check or money order for the amount quoted.
Send your digital manifold, freight prepaid, to
Fieldpiece Instruments. Send proof of date and
location of purchase for in-warranty service.
The meter will be repaired or replaced, at the
option of Fieldpiece, and returned via least cost
transportation.
For international customers, warranty for
products purchased outside of the U.S. should
be handled through local distributors.
www.fieldpiece.com
© Fieldpiece Instruments, Inc 2013; v32
High Side
Low Side
TXV
Compressor
Direction of
Refrigerant
Flow
Condenser
Evaporator
!
WARNINGS
DO NOT APPLY MORE THAN 800 PSI TO ANY PORT ON THE MANIFOLD.
FOLLOW ALL EQUIPMENT MANUFACTURER'S TESTING PROCEDURES
ABOVE THOSE IN THIS MANUAL IN REGARDS TO PROPERLY
SERVICING THEIR EQUIPMENT.