ESTechnical Reflow Oven Controller Upgrade T962A

Reflow Controller hardware v4

Instructions for fitting ESTechnical Reflow Oven Controller to T962A

Thank you for your purchase of ESTechnical products. If you have any questions or comments please let us know, we are always keen to hear feedback about our products.

Optional parts

NB: The USB connection and external thermocouple connector referred to in the operating instructions are optional and not included with this kit.

Please see Reflow Oven Accessories Package for more information. The items included in this package are also available separately, see Components and Consumables .


IMPORTANT – mains electrical wiring is involved in the installation of this controller, but no mains voltages are connected directly to the controller. If you are in any doubt please consult a qualified electrician.
Installation procedure

Auto Reset Jumper

The ESTechnical reflow controller v4 PCB and onwards has a jumper for enabling or disabling the auto-reset behaviour of the MCU. With the jumper connecting the two pins it is possible to easily upload new firmware to the controller via USB to serial connection from a computer. With the jumper open, the MCU will not automatically reset when the serial port is opened by a computer - this is more convenient in normal operation and we suggest that you operate the controller with the jumper open.

Auto reset jumper, disable auto reset by disconnecting the jumper
  1. Unplug the power cable from the reflow oven.

  2. Remove the drawer from the unit (pull forwards until it stops, then carefully undo the clips (gently move the plastic levers) that keep the drawer in the runners, then slide the drawer out from the runners. Set the drawer aside.

    Drawer runner clip
  3. Remove the screws that are under the front edge of the lid, there are two or three screws in the drawer opening, keep these safe.

    Front screws
  4. Turn the unit around so you are looking at the back, remove the screws that hold the lid on the case, keep these safe.

    Rear Screws
  5. Being very careful not to pull on any cables, carefully lift the back of the lid slightly, then gently slide the lid forwards until it unhooks from the lower part of the oven. Lift the lid off the oven, turn over and place it next to the bottom half of the oven.

  6. Gently pick off the hot glue that's covering the connectors on the control board. A small pair of pointed pliers is helpful here, only try to remove a small amount at a time.

    Remove all the glue from screws and connectors
  7. Disconnect all the cables that attach to the control board. Do not pull on cables, pull the connectors apart gently and without twisting.

    All connections unplugged
  8. Completely remove the control board and display and set aside – these items are no longer needed.

    Original controller and display removed
  9. You should have the following cables unplugged - at this point, take a moment to familiarise yourself with the wiring that is present. You need to be able to identify each of these cables in order to proceed with the installation.

    • Low voltage AC power cable from the small transformer, has a plug that fits onto two pins.

    • Small signal cable to the heater SSR, fitted with two pin JST connector.

    • Mains cable that was used to supply the power for the oven cooling fan to the ESTechnical Reflow Oven Controller, this has a three pin connector with only two terminals populated.

    • One cable that goes into the back of the oven, this is the oven cooling fan cable and has a two pin connector fitted.

    • 2x thermocouples with colour coded crimp ferrules to indicate polarity.

    • Keypad ribbon cable.

    • One cable that goes to the two panel LEDs, this has a 4 pole JST connector.

    • One cable that goes to the small DC cooling fan, with a 2 pole JST connector.

  10. Set aside the lid part of the oven for now.

  11. Carefully un-crimp the tubes that hold the thermocouples using a pair of pliers. Gently pull out the thermocouple.

    Thermocouple mounting tubes
  12. Inspect the thermocouples and if necessary untwist the wires so that the wires only touch when meeting the bead, the wires should not be twisted together leading to the tip. A small pair of pliers is needed – be careful the thermocouple is fragile. This reduces the mass of the thermocouple junction and improves the response time to temperature changes.

    Thermocouple tip prepared for refitting
  13. Re-mount one thermocouple in the front mounting tube and position the tip 10-15mm above the surface of the drawer (45-50mm above the inside of the oven with the drawer removed).

    Set the thermocouple height
  14. Gently crimp the tube with strong pliers to hold the thermocouple in place – do not crush the thermocouple wires. The other thermocouple is not needed - keep this as a spare.

    Refitted thermocouple
  15. Grind/file/sandpaper away the powder coated covering until you reach bare metal around one screw hole on the rear of the lid. This provides an earth connection to the back panel. The matching area on the rear panel of the oven also needs to be prepared in the same way so good metal on metal contact will be achieved when the oven is reassembled.

    Prepare a bare metal area around a screw hole for good earth continuity in the case
  16. Screw the supplied stand-off posts into the four screw posts at the corners of the display window inside the lid.

    Stand off posts mounted at the corners of the display area
  17. Carefully remove the protective film that covers the LCD on the ESTechnical controller. Try not to touch the display, install the controller immediately.

  18. Place the ESTechnical Reflow Oven Controller on the mounting posts for the display, making sure you have oriented it correctly. The Keypad ribbon cable should curl round and line up with the keypad connector on the controller.

    Controller mounting orientation
  19. Screw down the ESTechnical Reflow Oven Controller using the provided M3 6mm bolts – do not over tighten these screws.

  20. Plug in the thin ribbon cable for the keypad, the connector is labeled 'Keypad'.

    Keypad connection
  21. Identify the cable that connects to the panel LEDs, plug this onto the pins labeled 'LEDs' on the ESTechnical Reflow Oven Controller.

    LEDs connection
  22. Find the cable for the small cooling fan, plug this into CONN5, being careful to observe the polarity marked on the board. In some ovens, the fan polarity is not clearly marked, damage will not occur if it is connected in reverse, but the fan will not run. You may need to come back and reverse this connection.

    DC Cooling fan connection
  23. The installation of the controller in the lid is now completed, set aside the lid for now.

  24. It is necessary to improve the earth connection to the case of the oven, since the original manufacturer powder coats the panels and does not provide a good earthing connection. Unscrew the bolt securing the earth cable to the panel, remove the earth connection and refit the bolt.

    Original earth connection
  25. Being careful not to damage the cables, drill a 3.5mm or 4mm hole near the mains inlet.

  26. Sandpaper or grind away the coating around the newly drilled screw hole on the inside surface of the back panel. Be sure to expose the metal surface properly for a good earth connection.

    Earth bolt location and lid screw hole prepared on the inside of the panel
  27. Also prepare the area around the screw hole which matches up with the screw hole on the lid, prepared earlier. This ensures the lid and the back panel are well connected to the electrical earth.

  28. Using the supplied M3x8 bolt and self locking nut, bolt the earth connection from the inlet to the newly prepared earthing area.

    New earth connection
  29. Confirm that there is a low resistance connection between the earth pin of the power inlet and the metal case. Test between a screw head on the rear panel (but not the newly fitted earth bolt) and the earth pin of the power inlet. The resistance measured here must be less than 1 Ohm. Using a multimeter with a low Ohms range, the typical reading is about 0.15 Ohms. If the resistance is too high, confirm the correct function of the meter and if necessary improve the contact between the earth connection and the metal panel.

    Test the earth connection resistance is lower than 1 Ohm.
  30. Disconnect and unbolt the heater SSR. The small signal cable can be discarded, a replacement is provided.

    Remove the original heater SSR
  31. It is necessary to drill two extra holes so that the two new SSRs mount together as shown. Mark where you will drill first with a fine marker pen or pencil and double check the position of the marks by offering up the SSRs to their new mounting sites.

    Mark the locations of the SSR bolt holes
  32. Once you are satisfied that the location of the pen marks are correct, gently make a center punch mark on each mark; caution is required as the oven contains quartz heater elements.

  33. Before drilling, move all the cables out of the path of the drill.

  34. Pilot drill the SSR bolt holes with a small drill, eg 2-3mm.

  35. Drill the two SSR bolt holes to the final size needed, 4.5-5mm.

  36. Be careful to remove all drilling swarf and to clean up any sharp edges on the holes you drill (a counter-sink or larger drill bit turned by hand in the hole is good for cleaning the edges).

  37. Do not allow any small bits of metal to remain inside the oven housing!

  38. The masking tape in the T962A should be removed. If the tape is difficult to remove, heating with a hair dryer helps soften the tape adhesive and makes it easier to remove.

    Why is masking tape in here anyway?
    All masking tape removed
  39. Apply kapton tape (not supplied) to replace the masking tape.

    Replace the masking tape with kapton tape
  40. Pass the main fan cable under the 9v transformer and tuck the cable out of the way.

    Pass the fan cable under the transformer
  41. Mount both SSRs into the case firmly and ensure they are oriented with the low voltage control terminals in the center of the oven with the larger power terminals towards the edges, this will make the wiring easier later. Bolts for mounting the extra SSR are included.

    Solid State Relay (SSR) mounting positions
  42. Connect the wire coming from the heater to terminal 2 ~ on the heater SSR. This wire already has a fork crimp terminal fitted.

    Heater SSR connections
  43. Connect the remaining fork crimp terminal (which connects together a group of three wires) to the heater SSR terminal labeled 1 ~. See photo above.

  44. Identify the cable that goes to the exhaust fan at the back of the oven. Cut the two wires at the base of the plug.

    Fan cable (coiled)
  45. Choose one of the wires from the fan (either wire is OK), shorten this wire to an appropriate length to connect to the fan SSR terminal labeled 2 ~. Strip the insulation from the wire for about 5mm from the end, twist together the strands and then crimp on one red fork crimp (supplied).

    Fan wire shortened to connect to SSR
  46. Connect the fork crimp to the fan SSR terminal labeled 2 ~, the remaining fan wire can be seen in the foreground.

    Fan wire connected to lower terminal of SSR
  47. Identify the cable that previously supplied mains power to the fan driver on the original controller board. You can follow this cable back to the mains switch mounted on the back panel of the oven. Cut off the connector, remove the high temperature sleeve and save this as it will be reused.

    Mains cable (coiled)
  48. Separate the two halves of this two core cable by pulling the two halves away from each other. Take care not to damage the insulation or pull on the wires too hard.

  49. Identify the Neutral wire, this can be followed back into the group of wires connected to the heater SSR terminal 1 ~. Pass this wire through the high temperature sleeve that covers the supply wires to the 9v transformer.

    Feed neutral wire through sleeve (the end is shown coiled)
  50. Connect the Neutral wire (using the other red fork crimp) into the SSR terminal labeled 1 ~. You can shorten this cable to suit the new location.

    Fan SSR neutral connection
  51. Place both the heat shrink sleeve (provided) and the high temperature sleeve (provided) over the remaining wire to the fan.

    Fit both sleeves (provided) onto the fan wire
  52. This wire needs to be connected to the remaining live wire, this can be followed back to the switch terminals. These wires should be joined by first twisting together then soldering to form an overlap of at least 6mm.

    Fan wire connection - this needs to be soldered
  53. Shrink the heat shrink sleeve over the join with a hot air gun. Although the inside of the lid does not get very hot, it is advisable to cover the heat-shrink sleeving with the high temperature sleeve for extra thermal protection.

    Sleeved connection
  54. Connect the two supplied 50cm signal cables to the two input terminals of the SSRs.

    SSR signal connections
  55. Slide these cables through the heat-resistant sleeve that was recovered from an earlier step.

    Sleeved SSR signal connections
  56. At this stage the finished mains wiring should look like the following photo.

    Finished SSR installation
  57. Identify the output cable from the small mains transformer and cut off the plug.

  58. Strip about 5mm of the insulation off the end of the cable, twist together the strands of the wire.

    Prepared ends of the cable from the 9v transformer
  59. Optionally fit bootlace ferrules to the ends of the wires (not supplied and optional).

    Optionally fit bootlace ferrules (not supplied)
  60. At this point you should have the cables prepared as shown, these are the 9v AC power to the controller, SSR signal cables and main oven thermocouple cable.

    These cables connect to the controller
  61. Place the lid of the oven alongside the lower part of the oven. Connect the 9v AC to the power connector on the ESTechnical Reflow Controller. The two wires can go into the connector either way round as this is low voltage transformer isolated AC.

    Controller power connection
  62. Identify the thermocouple cable. The thermocouple mounted in the front of the oven drawer needs to be connected to the controller thermocouple input A. Make sure you observe the polarity of the thermocouple, it has one lead marked red (this is positive, marked + on the board) and the other is blue/black (-).

    Oven thermocouple connection (ignore the green cable in input B)
  63. Plug in the signal cable that goes to the Heater SSR, this fits to the two pins labeled 'Heater SSR' on the ESTechnical Reflow Oven Controller PCB. Observe the polarity marked on the controller board and SSR.

    SSR signal connections
  64. Plug the cable that goes to the Fan SSR onto the connector on the ESTechnical Reflow Oven Controller labeled Fan SSR. Observe the polarity.

  65. Carefully inspect the wiring of the oven, there should be no loose strands of wire sticking out from connectors, if there are any, redo the connection being careful to correctly insert all the strands into the screw terminal before tightening the screw. There should also be no plugs that are not plugged in and no remaining cables – if there are, go back and check.

  66. Confirm that there is no short-circuit in the mains wiring by measuring the resistance between the live and neutral terminals of the power connector. The main power switch must be in the on position for this test. This should measure around 500 Ohms, the approximate resistance of the primary winding of the 9v transformer.

    Test for mains short circuit (power switch must be in On position)
  67. Check there is no accidental connection between the mains wiring and the ESTechnical Reflow Controller. There are two options for this test depending on the meter(s) you have available:

    1. Using an insulation resistance tester: Measure the resistance (using an insulation resistance test mode set to 250v) between one of the 9v AC power connections and the mains wiring neutral connection. This should measure as open-circuit or a very high resistance, e.g. greater than 500MOhm. If this test shows a resistance of less than 500MOhm, check all connections are made as per the instructions and confirm the isolation between the primary and secondary windings of the 9v transformer with an insulation resistance tester set to a 250v test range.

    2. Using a standard multi-meter: Set the meter to the highest resistance measuring range eg 10MOhm. Measure the resistance between one of the 9v AC power connections and the mains wiring neutral connection. This should measure as open-circuit. This test is less thorough than the above option, but should alert you to any issues with this part of the installation.

      Insulation resistance test
  68. Return the power switch to the Off position.

  69. Inspect all wiring again before reassembly!

  70. Being very careful not to pull on or trap any of the cables, reassemble the oven by carefully placing the lid on (slightly forwards of where it needs to end up) and then slide it towards the rear of the oven.

  71. Fit the screws at the front of the oven in the drawer opening.

  72. Fit the screws on the rear panel of the oven.

  73. Refit the drawer to the runners taking care to accurately line up the rails with the ball bearings. Push the drawer until it closes. It may need opening and closing 2 or 3 times to feel smooth after reassembly.

  74. Now the oven is ready for testing. Plug in the power and switch on the oven, the display should illuminate and the ESTechnical Reflow Oven Controller will display the splash screen followed by main item of the menu. (If the display does not illuminate, switch off the power immediately and go back and check connections.)

  75. Check the small cooling fan is running, if not, go back and check the connection.

  76. Choose Cycle Start (navigate the menu with the < and > keys ) and press OK to start a reflow cycle. The main fan should begin to gently idle and the heaters should begin to heat up. Press the 'S' key to stop the cycle. The ESTechnical Reflow Controller will go into cool-down mode. The fan will stop when the oven returns to near room temperature. The cooling down display can be interrupted without interrupting the cooling of the oven to access the menu, just press the 'S' key again. If the fan does not start or the temperature does not begin to rise, switch off the oven immediately to prevent any possible damage and go back to checking all connections. See troubleshooting for suggestions.

  77. Proceed to the operating instructions.


ESTechnical accept no responsibility or liability for personal injury or damage to property – it is the user's responsibility to correctly carry out installation and confirm the correct operation of the oven once installed.
Reflow Controller Installation Troubleshooting
Issue Cause Solution
Controller does not power on when oven is switched on Incorrect connection of low voltage AC supply to controller Check connection of low voltage AC power supply to the ESTechnical Reflow Controller.
Mains power is not supplied to the 9V transformer Check the primary winding of the 9V transformer is connected between the switched live feed of the oven and the neutral terminal
Fan or heater does not work during a reflow cycle Incorrect connection of signal cable between Reflow Controller and SSR Check the polarity of the connection and correct if necessary, the polarity is marked on the controller and the SSR terminals
Incorrect mains power or SSR connections Check the connections between the mains power, SSRs and loads (heater and fan) are made as per the instructions
DC cooling fan does not start Incorrect connection of the DC cooling fan to the ESTechnical Reflow Controller Check (and possibly reverse) the connection on the controller to the DC cooling fan, the wiring colours used by the original oven manufacturer are inconsistent and can be misleading
LED indicators do not light during a reflow cycle Incorrect polarity connection of the LEDs to the ESTechnical Reflow Controller Check (and possibly reverse) the connection on the controller to the LEDs, the wiring colours used by the original oven manufacturer are inconsistent and can be misleading
When a reflow cycle is started the temperature reported on the display drops instead of rising Thermocouple connection is reversed Correct the reversed thermocouple connection
Controller displays “Thermocouple input open circuit” Incorrect connection of the thermocouple to input A of the ESTechnical Reflow Controller, or broken thermocouple Disconnect the thermocouple from input A and measure the resistance of the thermocouple, it should measure less than 10 ohms. If the thermocouple is open circuit, replace the thermocouple.
Controller displays “Temperature following error during heating” Thermocouple is incorrectly placed Confirm the placement of the thermocouple is as per the installation instructions and adjust if necessary
There is no PCB in the oven drawer The temperature following error can occur when the oven drawer is empty and a cycle is run, test with a PCB below the oven thermocouple
The Fan Idle Speed is set too high Ensure the Fan Idle Speed is set to the correct value as suggested in the installation instructions
The Ramp up Rate is set too high for the PCB(s) currently in the oven Reduce the Ramp up Rate setting slightly and test again

ESTechnical Reflow Oven Controller Operating Instructions


ESTechnical accept no responsibility or liability for personal injury or damage to property – it is the user's responsibility to correctly carry out installation and confirm the correct operation of the oven once installed.
Initial Set Up
  • Place the Reflow Oven on a hard, level, heat resistant surface
  • Attach the power cable to the reflow oven and plug in to a power outlet
  • Ensure none of the grilles on any panel are covered
Overview of Operation
Initial Set Up for new PCB designs
  • Prepare one or more test PCBs with a thermocouple attached
  • Load the default profile settings
  • Perform a test reflow cycle and observe the board temperature
  • Adjust the cycle settings in small increments and repeat the test cycle (with oven and PCB starting from near ambient temperature for every test) until the profile meets the needs of the solder paste and components used on your PCB(s)
  • Save these profile settings and make a note of the profile number in your project documentation for the PCB
Production of PCBs

Once you have set up a reflow profile for your PCB design:

  • Prepare PCBs with solder paste and components
  • Select the correct profile for the board design
  • Place PCB(s) in the reflow oven drawer
  • Run the cycle
  • Remove soldered PCB(s) once the oven has cooled
  • Repeat as needed

Navigate the menu using the keypad keys < & > to move through the menu items, press Ok to select a menu item. Pressing Back will return you to the previous level of the menu.

The menu is organised as follows:

Menu layout

  • Start Cycle
  • Edit Profile
    • Ramp up rate
    • Soak temp
    • Soak time
    • Peak temp
    • Peak time
    • Ramp down rate
  • Load Profile
    • Choose profile number
  • Save Profile
    • Choose profile number
  • Fan Settings
    • Idle speed
    • Save
  • Factory Reset
Reflow Profile Testing

The ESTechnical Reflow Oven Controller is equipped to make setting up reflow profiles easy – it is essential to carry out this testing correctly to ensure correct profile settings are used for your board(s).

Profile testing should be carried out for each design of board to be soldered.

To carry out profile testing, you will require a test PCB, kapton tape and heatsink compound.

Test PCB, kapton tape, heatsink paste and thermocouple

Decide where to place the thermocouple. Where you place the thermocouple on the PCB depends largely on the design. Densely populated areas or areas with large copper fills are a good choice for initial testing. Other areas of the board (for example, the top of tall parts) should also be measured once a suitable reflow profile has been set up to ensure the peak temperature is not exceeding the manufacturer's stated limits.

Small boards with few parts are often easy to profile correctly with no parts present, as the parts comprise a very small amount of the overall mass of the board. More densely populated boards may require further adjustments to the profile to adequately reflow all solder joints. Further testing is advised to ensure safe margins are kept from the maximum temperature specified for the most sensitive parts.

Secure the thermocouple cable with kapton tape while holding the tip in the correct location. Ensure the cable is well stuck down to provide some strain relief to prevent the tip of the thermocouple moving. It can help to strip back some of the outer layer of thermocouple sleeve.

Stick down the thermocouple cable securely with the tip held in the correct location

Apply heat sink paste to the tip of the thermocouple. Only apply a very small amount to ensure good thermal coupling between the PCB and the tip.

Apply heatsink compound to the thermocouple tip

Apply a thin strip of kapton tape over the thermocouple wires, very close to but not touching the tip of the thermocouple. Ensure this is well stuck down and the tip is making good contact with the PCB.

Apply more kapton tape to ensure good contact between the thermocouple tip and the PCB

Place the prepared PCB in the reflow oven, route the thermocouple cable out of the drawer at one side and fully close the drawer. Ensure the PCB is placed underneath the thermocouple mounted in the front of the oven. Plug the thermocouple into the thermocouple socket on the side of the reflow oven.

Run a test cycle and observe the temperature profile of the PCB. Make adjustments as necessary to the profile settings after each test profile, repeat until the profile temperature measured on the board is suitable for your parts and solder paste recommendations. Ensure the maximum temperature for the most sensitive part(s) are not exceeded.

Profile testing can be carried out by carefully watching the temperature reported for the PCB thermocouple, or by logging the data via the USB port and using the ESTechnical reflowViewer software (see below). Alternatively it is possible to use an external thermocouple meter to monitor the PCB temperature. Adjustments should be made to the profile settings based on the observed temperature of the PCB.

Ideal Fan idle speed Adjustment

If the PCB temperature does not closely follow the profile temperature settings, consider carrying out Fan Idle Speed Adjustment procedure.
Data Logging – ReflowViewer Software

ETechnical provide a simple live data graphing application for use with the reflow oven, this aids adjusting profile settings and helps reduce the number test cycles performed for each design. The software allows easy adjustment of the reflow profile settings stored in the oven controller.

For more information, see

Operating Instructions
Starting a reflow cycle

Navigate to Cycle start in the menu and press OK. The controller will perform the cycle using the current cycle settings.

Stopping a cycle

Should you need to abort a reflow cycle, press the S key. The oven will move into the Cool down state. Observe the temperature on the display before attempting to open the drawer or remove boards.

Saving an edited profile

To save a profile navigate to Save Profile and press OK. Choose a profile number to save (by default all 30 profiles are the same, the user can save to any of these profiles) and then press OK. The profile is now saved in the chosen profile number.

Please note that any previous settings in the profile number you save to will be overwritten with the new settings.

Loading a saved reflow profile

Navigate to Load Profile and press OK, using the < and > keys, choose the profile number you wish to load. Press OK, the reflow profile settings will be loaded. When running a reflow cycle, these settings will now be used.

Editing the active profile

Navigate to Edit profile and press OK, then navigate to the parameter you wish to edit. The options are Ramp up rate, Soak temperature, Soak duration, Peak temperature, Peak duration and Ramp down rate. Press OK once you have selected the option to edit, the controller will display the value and allow editing using the < and > keys. Press OK to confirm your changes, or to cancel press Back. Repeat these steps to edit each parameter you wish to adjust.

When running a reflow cycle, the controller will use the settings as per your adjustment.

N.B. This process edits the variables stored in RAM and does not save the changes permanently until you save the profile.
Fan Idle Speed Adjustment Procedure

The oven's cooling fan is used to provide a small amount of air movement inside the oven, this helps the oven evenly heat the PCBs. The speed of the fan is important, too fast and the oven is being actively cooled while trying to heat up, too slow and the PCB will be heated unevenly.

The fan is run at a fixed 'idle speed' during reflow to provide a small amount of air movement in the oven. The fan should idle very slowly, to adjust the idle speed:

  • Navigate to Fan settings in the menu.
  • Press OK, Idle Speed will display on the screen.
  • Press OK to edit. (The default value for the fan idle speed in T962A is 35, for the T962 the default is 15.)
  • Test this idle speed by starting a reflow cycle, the fan should start up easily but not run so fast as to cause the oven to be cooled dramatically during reflow.
  • It is very important this value is set high enough for the fan to start every time the cycle is started (at low values, the fan will not be able to start spinning) but it is equally important not to set this speed too high, otherwise the fan forces too much cool air into the oven and reduces the efficiency of reflow soldering.

If the PCB temperature profile does not follow the programmed profile settings closely:

  • Set the Fan idle speed to a low value and ensure that the fan starts when a reflow cycle is started.
  • Perform a test profile using a PCB with thermocouple and observe the resulting temperature profile of the PCB.
  • Increase the Fan idle speed by 5-10 and repeat the test cycle without changing any profile settings.
  • When the PCB temperature accurately tracks the programmed profile temperature, note the Fan idle speed value and ensure it is saved.
Profile tuning tips

To get the best from your reflow oven, it is advisable to perform a series of tests to determine the settings required to properly reflow each design of board you work with. Boards of different masses will behave differently and may require different soak duration, temperatures etc. to properly reflow all solder joints on the board.

Refer to the data sheets for all the parts you use to determine the allowable reflow profile for the design. Once the peak temperature of the most sensitive part is known, this must not be exceeded anywhere on the board.

The board's temperature lags behind the heat of the heater tubes, the oven controller is not controlling the board temperature directly, but the air temperature inside the oven via the thermocouple mounted above the PCB. However, the surface of the PCB will absorb more energy than the thermocouple directly due to the IR radiation, meaning that it is possible for the PCB temperature to overshoot the air temperature in the oven.

The PCB temperature should always remain below or equal to the profile temperature set using the controller; until cooling begins. If the soak duration is too long or the ramp rate too slow, the board temperature will exceed the soak temperature before the soak stage of the profile is completed. This will cause the temperature of the board to remain above the profile temperature that has been set, resulting in the peak temperature being higher than required.

There is an offset between the air temperature and the board temperature. Often, the peak board temperature is higher than the air temperature measured immediately above the boards. Be aware of this when choosing profile settings as a peak temperature of 220°C can result in a peak board surface temperature of 240-250°C. If the fan speed is set too slow, this offset can be even larger. Performing testing (see Reflow Profile Testing) will allow you to determine the best settings for a given board.

Towards the end of the peak stage of the reflow cycle, the board will reach its own peak temperature. During cooling, the air temperature needs to drop quickly below the melting point of the solder and continue to decrease to adequately cool the board.

Ideal Fan idle speed Adjustment

If the PCB temperature does not closely follow the profile temperature settings, consider carrying out Fan Idle Speed Adjustment procedure.

To work out the best profile settings adjust the following, one at a time, in small increments, in this order:

  • Soak time
  • Soak temperature
  • Peak temperature
  • Ramp up rate (as a last resort for heavy boards)

Repeat the test cycle to confirm the effect of the adjustment. If the PCB temperature overshoots the soak or peak temperature by more than 2°C, abort the reflow cycle and reduce the soak or peak duration appropriately. When the reflow cycle is aborted the oven will immediately begin cooling, wait for it to reach ambient temperature before beginning another test cycle.

Any of these changes alone can be enough to alter the profile to be suitable for your needs, take small steps to avoid large unexpected changes. A small change to the soak duration can have a large effect! The board temperature profile should not completely level off or begin to drop during soak, it should continue to climb slowly toward the desired soak temperature. If the board temperature exceeds the soak temperature before the end of the soak stage, reduce soak duration.

When viewing and adjusting reflow profiles, there are a few crucial points during the cycle to examine:

  • When transitioning from soak to ramping up to the peak temperature, the PCB temperature should have almost equalised with the oven temperature. If the PCB temperature is rising past the programmed soak temperature, the soak duration is too long. If this occurs, the PCB temperature will likely be too high for the remainder of the cycle.
  • At the start of the peak stage of the reflow cycle, the oven and board temperature should be a few degrees below the desired peak temperature, if the board temperature is overshooting the desired peak temperature, either increase the fan idle speed slightly or reduce the soak duration.
  • When cooling down, the air temperature of the oven needs to drop a lot faster than the desired board cooling temperature to ensure the desired board ramp down rate is met. It takes several seconds for the air temperature in the oven to begin to reduce at the start of the cooling phase. Ensure that the duration of the Time Above Liquidous is appropriate for your solder paste and parts.
Care and Maintenance

ESTechnical recommend the following care and maintenance should be carried out at the intervals specified in order to get the best performance and longest useful life-span from your reflow oven.

Before every use
  • Check that the oven has adequate air flow around it and that no grilles are covered.
  • Ensure the drawer is clean and free from dirt, dust or other potential contaminants.
  • Start a reflow cycle with no PCB(s) in the drawer, confirm that the main cooling fan starts to idle gently, abort the reflow cycle.
After every 50-100 reflow cycles
  • Remove the drawer from the oven, clean the drawer and internal surfaces of the oven being careful not to damage the oven thermocouple or heaters. Flux deposits will harm the performance of the reflow oven, remove these with flux thinners or a dedicated reflow oven cleaner such as Electrolube ROC.

Packing list

  • 1x ESTechnical Reflow Oven Controller PCB with LCD display
  • 2x 25A SSR
  • 4x 8mm M3 stand-offs – male to female threads
  • 4x M3 6mm bolts
  • 1x M3 8mm bolt with nyloc nut
  • 2x M4 x 16mm bolts with nuts
  • 2x 50cm two pole signal cable with 2.54mm pitch header connector to bootlace ferrules
  • 1x 50mm 3mm dia. heat shrink sleeve
  • 1x 75mm 6mm dia. high temperature sleeve
  • 1x Installation manual
  • 1x Operation manual

What you will need (not supplied):

  • Screwdrivers
  • Multi-meter (ideally with 250v insulation resistance test mode)
  • Allen keys
  • Wire cutters
  • Wire strippers
  • Crimp pliers
  • Small pliers to help grip the nut when fitting the Solid State Relays (SSRs)
  • Electric drill
  • Various sizes of drill; 2mm and larger suitable for drilling steel
  • Sharp pencil for marking panel
  • Center punch and hammer (for marking where to drill)
  • Metalwork files
  • A container for screws
  • Soldering iron
  • Solder
  • Hot glue gun and glue sticks
  • Hot air gun or other suitable tool for shrinking heat-shrink sleeve

EC Declaration of Conformity

In accordance with EN ISO 17050-1:2004

We, ESTechnical


12 Ormonde Road,
CT20 1PG,
United Kingdom

in accordance with the following Directive(s):

2004/108/EEC The Electromagnetic Compatibility Directive
2011/65/EU ROHS 2

hereby declare that:

ESTechnical Reflow Oven Controller

when installed and operated as per the supplied instructions the equipment named above complies with all applicable Essential Requirements of the Directives.

Signed by: Ed Simmons

Position: Founder

Carried out at:
12 Ormonde Road,
CT20 1PG,
United Kingdom

16th September 2013

reflowcontroller/t962acontrollerupgradev4.txt · Last modified: 2017/05/25 16:15 (external edit)