Slow heating resulting in < 1 degrees Celsius per second heating slope. #264
Description
Hello,
I have recently acquired a 110V version of Puhui T-962A reflow oven directly from puhui in China for my side projects.
I replaced all the mask tape with kapton taps and completed the cold junction mod and flashed the latest open-source firmware.
(So we can confirm that the 2025 version is still compatible with this open-source firmware.)
However, I am having some problems that I would like to seek some suggestions.
With min fan speed set to 8, using the Ramp test profile, I observed my oven heats about 1-1.5 degrees Celsius per second before 200 degrees.
After that it only heats at about 0.5-0.6 degrees Celsius per second. Thus, it never hits the 245 degrees Celsius target.
(The heating curve is shown in the following photo.)
Even If I adjusted the min fan speed to 0 and start at 90 degrees Celsius, it only barely reaches 245 degrees Celsius at 240s mark in the profile.
(The heating curve is shown in the following photo.)
This makes the oven unfeasible for reflowing because It would cook the chips before melting the solder.
I confirmed the 4 IR tubes were glowing red and the Lamp light was always on during the heating process.
I think it has a bad thermal isolation or under-powered heating element, but seeing others have dissembled pictures not different from mine while having successful results confused me.
I am kinda lost at this point and would like to ask that whether someone else has a similar problem and have a working solution for it?
Any suggestion are welcome.