Fieldpiece HVAC Guide HG1 Field Manual Download Page 11

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2.3 Superheat OUTPUT FORM

Figure 10. Superheat Test OUTPUT FORM.

Press OUTPUT for the Superheat OUTPUT FORM.

Target SH

(Superheat): Indicates what the superheat

should be as calculated from outdoor dry bulb and

indoor wet bulb

Actual SH

(Superheat): Shows the superheat calculated

from the measured suction line temperature and suc-

tion line pressure.

Vapor Sat:

This is the saturation temperature of the re-

frigerant in the evaporator coil. This is the temperature

a refrigerant will boil at a given pressure. It is one of

the temperatures from which superheat is calculated.

The

Actual SH

(superheat) should be within ±5°F of

the Target SH to ensure optimum performance. If the

ac-

tual SH

is outside this range, modifications to the charge

or adjustments to the restrictor (TXV) are necessary.

Adding refrigerant lowers your Actual SH. Recover-

ing refrigerant increases your Actual SH. The amount of

refrigerant necessary to add or recover will vary based on

the size of the system and the difference between the Ac-

tual and Target SH.

Because everything within the system is interdepen-

dent, one adjustment can affect other parts of the system.

For example, increasing airflow increases the superheat,

which may require adding refrigerant. After modifica-

tions, allow 15 minutes to stabilize and then retest.

Superheat and Subcooling FAQ

Q: How do superheat/subcooling tools work?

Superheat tools measure suction line pressure and

suction line temperature, and calculate the actual su-

perheat. Subcooling tools measure the liquid line pres-

sure and liquid line temperature and calculate actual

subcooling. The refrigerant charts for calculations are

incorporated into the software of the HVAC Guide

analyzer.

Q: When should I take my actual and target

superheat/subcooling?

Superheat and subcooling readings must be taken

when the system is in a steady state. Typically a resi-

dential system will be in a steady state after 10-15 min

utes. Turn the system on and set the thermostat low to

ensure that the system doesn’t turn off during your

testing. Once the system’s temperatures and pressures

are not fluctuating, the system is in a steady state.

Wet bulb temperature, outdoor dry bulb, suction line

pressure and suction line temperature must be taken

within a short time period to ensure valid results.

Conditions that affect your target superheat and tar-

get subcooling can change by the minute.

Q: What do I do with my ACTUAL superheat

or ACTUAL subcooling measurements?

Compare actual readings against the target superheat/

subcooling. As a general rule, if superheat is too high,

add refrigerant. If too low, remove refrigerant. If sub-

cooling is too low, remove refrigerant. If subcooling is

too high, add refrigerant. Consult the manufacturer’s

specifications before adding or recovering refrigerant

as further diagnostic tests may be needed

Continued on page 27

Diagnostic text and sections of manual

with more information about this test.

If Target SH and Actual SH are more than

5°F apart, as in this example, you need to

make adjustments to the system.

Boiling point is used to calculate Superheat.

Summary of Contents for HVAC Guide HG1

Page 1: ...IELDPIECE COM WWW FIELDPIECE COM WWW FIELDPIECE COM WWW FIELDPIECE COM WWW FIELDPIECE COM WWW FIELDPIECE Field Manual Models HG1 HG2 v 38 ...

Page 2: ...d furnace or water heater will cause your customers to call you and complain about the temperature being too cold or the hot water not be ing hot enough Use the Combustion test built into the HVAC Guide analyzer to determine if you have the right air fuel mixture by analyzing the combustion products You can then make adjustments to ensure the equip ment works as it should The CheckMe test model HG...

Page 3: ...nect accessory heads here Input Jacks Turns on the backlight for 30 sec Backlight Button Displays INPUT FORMS and OUTPUT FORMS Dot Matrix LCD Display Navigate within FORMS and screens Arrow Buttons Rotates to select test Switch Position Dial After POWER OFF clears unscrew the two screws to replace the 6AA batteries Battery Cover Recalls previous tests within each switch position Previous tests can...

Page 4: ... C system has the proper airflow per tonnage the actual evaporator exit temperature must be within 3 F of the target evaporator exit tempera ture as outlined in CA title 24 Superheat For a fixed restrictor air conditioning sys tem the HVAC Guide analyzer uses the indoor wet bulb and outside dry bulb to calculate a target su perheat and uses the suction line temperature and pressure to calculate ac...

Page 5: ...ing the RIGHT arrow and then character by character use the UP DOWN arrows and the RIGHT arrow to type in the value When finished press ENTER Read the OUTPUT FORM Figure 2 OUTPUT FORM for the Superheat test To display the OUTPUT FORM fill in the INPUT FORM correctly and press the OUTPUT button or scroll down If the INPUT FORM is missing inputs the appropriate lines on the OUTPUT FORM will be blank...

Page 6: ...WWW FIELDPIECE COM WWW FIELDPIECE COM WWW FIELDPIECE COM WWW FIELDPIECE COM WWW FIELDPIECE What Accessory Heads Do I Need Refer to the chart below to find the recommended accessory head and thermocouple for each measure ment Automatically input measurements with Field piece accessory heads for maximum accuracy and speed or manually input from Fieldpiece standalone instruments or non Fieldpiece tes...

Page 7: ...e gives you an indication of the proper indoor airflow This test can be easily per formed simultaneously with superheat or subcooling tests If actual evaporator exit temperature is more than 3 F above or below the Target Evaporator Exit Tempera ture an airflow problem may exist Ensure that filters are clear dampers are adjusted properly and the fan speed is set correctly if it can be varied The Ta...

Page 8: ...st big enough for the probes Seal any holes before leaving the jobsite Out of Evap Supply DB dry bulb temp leaving the evaporator Measure in the center of the supply plenum Punch a small hole in the supply plenum and insert a calibrated dry bulb thermocouple such as the ATA1 or ATB1 Make sure the thermocouple is in the center of the plenum cross section Seal the hole when finished Can be measured ...

Page 9: ...ing superheat is the best way to obtain proper refrigerant charge for a fixed restrictor metering device system If the air conditioner is in good working order and the airflow is adjusted properly comparing the actual and target superheat will tell you if refrigerant needs to be added or recovered Ensure the pressure never ex ceeds the manufacturer s maximum overload pressure guidelines On a fixed...

Page 10: ...turn grill since temperatures change by the time the air reaches the indoor coil Wet the wet bulb sensor ATWB1 and insert it after 15 minutes of continu ous running Clip downstream of the filter if the filter is just before the air handler Clip on the side facing the evaporator and take the measurements If the filter is not before the evaporator make small holes in the return plenum just big enoug...

Page 11: ...odifica tions allow 15 minutes to stabilize and then retest Superheat and Subcooling FAQ Q How do superheat subcooling tools work A Superheat tools measure suction line pressure and suction line temperature and calculate the actual su perheat Subcooling tools measure the liquid line pres sure and liquid line temperature and calculate actual subcooling The refrigerant charts for calculations are in...

Page 12: ...cing efficiency Subcooling is the best way to obtain proper refriger ant charge for a TXV EXV system If the air conditioner is in good working order and the airflow is adjusted properly comparing the actual and target subcooling will tell you if refrigerant needs to be added or recovered ensure the pressure never exceeds the manufacturer s maximum overload pressure guide lines In a properly workin...

Page 13: ...onnect the ASX14 to the liquid line service port Set the acces sory head to measure pressure and ensure the read ing stabilizes before locking in the reading Enter data manually if you want to get pressure from your gauges The analysis is only as good as the measure ments The Fieldpiece ASX14 has better resolution than most gauge sets LL Temp liquid line temperature Measure near the same location ...

Page 14: ...3 F apart as in this example you need to make adjustments to the system Boiling point is used to calculate Subcooling Diagnostic text and sections of manual with more information about this test Superheat and Subcooling FAQ Part 2 continued from page 21 Q What if myACTUALS are far different from my TARGETS but the system seems to be running properly A Many poor performing systems have actual super...

Page 15: ...effective ness of the combustion by analysis of combustion prod ucts and temperature The Combustion Test will only tell you about com bustion and does not take into account any losses from poor insulation or cycling and standby losses It does not measure any losses in the distribution system such as uninsulated hydronic piping air duct leakage or in sulation levels Properly tuned gas combustion eq...

Page 16: ... start of the flue Flue Temp Connect the ATR1 temperature probe to the AOX2 Set the AOX2 on TEMP and measure the temperature of the combustion products in the flue stack 18 inches from the start of the flue CO Connect the ACM3 and take a sample of the com bustion products in the flue stack in the same location as the O2 measurement within 18 from the start of the flue Primary Temp Measure the temp...

Page 17: ...rners Oxygen O2 6 9 Stack Temperature 400 600 F CondensingOil Oxygen O2 3 7 Stack Temperature 90 140 F 4 From Carbon Monoxide a Clear and Present Danger Third Edition Dwyer Leatherman Manclark Kimball Rasmussen ESCO Press 2003 Erik Rasmussen Erik Rasmussen has been an expert in the com bustion analysis field for over 20 years Rasmussen has helped Fieldpiece in providing many of the tables and much...

Page 18: ...than looking at individual aspects of the air conditioner The CheckMe position has diagnoses that will help you pinpoint problems with the system Besides provid ing better diagnoses it also checks the test numbers and warns you if there is a likely testing error In these cases you will want to retake some measurements CheckMe in the HG2 will analyze with almost any amount of data The more informat...

Page 19: ...wet bulb temperature is the sta bilized reading If the sensor starts to dry out the reading will rise and the wrong temperature will be recorded If the filter is not directly upstream of the air handler make small holes in the return plenum just big enough for the probes Seal any holes before leaving the jobsite Supply DB dry bulb leaving the indoor coil Mea sure in the center of the supply plenum...

Page 20: ...mation please visit www energyconservatory com TrueFlow Default NO If NO skip ahead to the Customer ID Answering YES unlocks the inputs for this section Nom Ton Nominal tonnage of the A C system Grid Size Default 14 inches Other selection 20 inches Choose the grid size you are using 7 TrueFlow is the registered trademark ofThe Energy Conservatory Sup Plen Pres TrueFlow system operating pressure wi...

Page 21: ...nputs are simply for bookkeeping and are not used for any diagnosis or performance calculations By turning these to Yes you will see them on the INPUT FORM when this grant is selected List of inputs Indoor Model No number Furnace Model No number ID VOLTS voltage of indoor unit ID Full Ld Amps full load running amperage of indoor unit Sup Plen Press supply plenum pres sure static Ret Plen Press ret...

Page 22: ...d due to incorrect refrigerant charge Higher than expected airflow is rare but does occur occasionally Measuring the airflow directly would identify if high airflow is the cause of the low temperature split 5 407 High airflow possibly reduce airflow The indoor coil airflow was directly measured using the TrueFlow grid and is higher than expected Con sider reducing the airflow particularly if the u...

Page 23: ...refrigerant Since the test conditions are hot outside dry inside or both the exact target super heat cannot be determined Because the actual super heat is greater than 6 F the unit is undercharged Add refrigerant until the superheat is 6 F 5 508 Charge unknown raise indoor tempera ture to obtain a target superheat 5 F and retest Since the test conditions are hot outside dry inside or both the exac...

Page 24: ...cturer or dis tributor and verify the size is appropriate for the air conditioner 5 602 Probable oversized metering orifice consult manufacturer s specifications The metering orifice lets too much refrigerant through Check that the orifice is sized properly Find the metering device part number and obtain the orifice size from the manufacturer or distributor and verify the size is appropriate for t...

Page 25: ...pacity Check the refrigerant charge repair if needed and retest 5 903 Low capacity check compressor amps and coil saturation temperatures Full diag nosis of this situation requires a complete set of data including compressor amps high and low side pres sures and liquid and suction line temperatures 5 10 Heat Pump in Heating Test the refrigerant charge for a heat pump in the sum mer in the cooling ...

Page 26: ...data or any grants you have created You can also check your version of firmware to see if you are up to date and your memory status to see how much memory you have left You can also communicate with the PC and transfer data to and from with the Com with PC option See page 56 for more details Figure 22 Screenshot of Memory MEM switch Units On every INPUT FORM there is a Units line The default is En...

Page 27: ...when in an INPUT FORM to save test data Test data is saved along with Customer ID and a time stamp You will be prompted to input a Customer ID before saving Figure 25 Saving data for Superheat analysis Recalling SavedTests While in the desired test press the RECALL but ton to access previously saved test data Highlight the Customer ID from the list and press ENTER and then highlight the date and t...

Page 28: ...nstall PC Software for your operating system Follow the on screen in structions 3 Exit out of the installation screen Overview Communicating with a PC 1 Make sure the HVAC Guide analyzer is off Plug the IR2 USB cable into the bottom of the HVAC Guide analyzer 2 Plug the USB end of the IR2 USB cable into a USB port of your PC 3 Turn the dial to MEM on the HVAC Guide ana lyzer 4 Scroll down to Com w...

Page 29: ...WW FIELDPIECE Transferring Tests from the HVAC Guide Analyzer to a PC 1 Press the Transfer arrow pointing to the right 2 Highlight the files you wish to transfer to the desti nation folder on your PC and press the Transfer to PC button to transfer 3 If you want to change where the files are saved to press the Browse Desination button Browse your PC for a folder in which you would like to save the ...

Page 30: ...OM WWW FIELDPIECE COM WWW FIELDPIECE COM WWW FIELDPIECE Transferring Tests From a PC to the HVAC GuideAnalyzer 1 Press the Transfer arrow pointing left 2 Click to highlight any files you wish to transfer to the HVAC Guide analyzer and press Transfer to send 3 If you want to change where the files are located on your PC press the Browse button Browse the PC for a folder containing files for transfe...

Page 31: ...wed by the test type and the time stamp in the following format xxxxxxxxxxwwYYMMDDhhmmss xls Where x s rep resent the Customer ID and ww represents the abrevia tion of the test performed ET Target Evaporator Exit Temperature SH Superheat SC Subcooling CA Combustion Analysis CM CheckMe Once you have opened the file you can print it from your PC Figure 28 Test Data on PC Editing Jobsite Information ...

Page 32: ...er while starting the program Figure 32 COM Port Setup Reconnect the HVAC Guide analyzer select Com with PC press ENTER and press AUTO Detect to re establish the connection with the HVAC Guide analyzer You can look in the Windows Hardware Wizard to see if the HVAC Guide analyzer is communicating properly with the PC and to troubleshoot the driver if it is not Keep Your HVAC Guide Updated The lates...

Page 33: ...d to subcooling After the restrictor refrigerant enters the evaporator at a low temperature and pressure and boils evaporates into a gas by absorbing heat from the indoor air The re frigerant stays at the same temperature and pressure un til all the refrigerant evaporates into a gas After the re frigerant becomes a gas it will become superheated and the temperature will change The superheat measur...

Page 34: ...e rise to match the appliance manufac turers specifications will increase the efficiency and help to maximize the performance and life expectancy of the equipment It is also safer because the equipment will produce minimal CO as a byproduct A properly tuned atmospheric natural gas or pro pane fired appliance will have approximately 6 to 9 O2 in the flue gases Fuel oil appliances with flame retenti...

Page 35: ...eared from the display before removing batteries Battery AA x 6 Operating environment 0 C 32 F to 50 C 122 F at 70 R H Storage temperature 20 C 4 F to 60 C 140 F to 80 R H with battery removed from meter Dimensions 210mm 8 27in H x 80mm 3 15in W x 30mm 1 18in D Weight approx 400g 0 88lb including battery Accessory Head InputVoltage DC Ranges 400mVDC 4VDC DC Accuracy 0 5 rdg 2dgts AC Range 400mVAC ...

Page 36: ...king with Fieldpiece Instruments to create a better tool for the diagnosis of air conditioning systems in the real world Proctor s research exposed the need for tuning air conditioners and prompted the California Energy Commission to add the procedures to Califor nia s Title 24 Building Standards John Proctor is a professional engineer 1965 gradu ate of MIT and wrote most of the residential coolin...

Page 37: ...72 WWW FIELDPIECE COM WWW FIELDPIECE COM WWW FIELDPIECE COM WWW FIELDPIECE COM WWW FIELDPIECE COM WWW FI ...

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