Please help! I have no idea what I did wrong. I setup everything just so and boom my ESP is dead. On USB the PC sees it, but won't flash and got REAL hot.
Here is an ascii schematic.. it took 30 minutes to do, so don't complain it's convuluted..... sigh..
So I hooked up C wire first, then when I attached the RH, the FAN went on... I was startled when this unexpectly happened, as Fan should go on when RH --- > G, NOT RH ----> C, besides, there isn't a short on the board between it's blue and red lines. I was very upset I burned a precious ESP32 and began measuring resistances of the board... nothing significant to report. I also, sans the LLC and ESP32, tried hooking back up to RH and C... the fan still kicked on, and when I disconnected the wire, I got quite a spark. I was trying to see if High voltages were getting past the L7805 for some reason, but I acutally read a 0.0V on the ouput of it. After several tries or RH & C, the thing must of blown a fuse. So I'm out a ESP32 AND the damned AC. Shit.
AND the ascii art I prepared is scewed up becuase characters are spaced differently on the final post vs preparation.
[ L 7805 ]
HVAC RH (red) _______ ~ I G O
| / \ +| | |
| _ - \ / | |
| | ~ | |
| ||| |
| | |
| | |
| | |
| | 16v / | ____________________
| | 200uf | | _______ vin
HVAC C (blue) __)|_ | ( ||HV| |LV 3.3v |
| | ____________ A | | A ___ 13 | E
| | | _______ B | LLC | B ___ 14 | S
| | | | __ C | | C 15 | P
|)_____ | | | | |
| | | | | | ||
| | ~ + | |
| | HVAC G (Fan)________ ~[ SSR A ] | |
| | - | |
| |_______________________| | |
| | + |
| | HVAC W (Heat)______ ~ [ SSR B ] |
| | ~ - |
|)| | |
| | | +
| | HVAC Y (Cool)) ~ [ SSR C ]
| | | ~ -
| |_______________________________|)|
|___________________________________________|
The ascii art I prepared is screwed up because characters are spaced differently on the final post vs preparation.
Well, I admire the effort you put into it but ultimately it makes no sense at all to me. Please get a writing stick and some papyrus and draw a schematic, then photograph it and post that.
Powering the ESP should be with and only with a 5V regulator. What did you hook to the 3.3V side of the ESP? I found that the 3.3V side of the ESP, produced by the 5V ESP regulator, can 2 or 3 3.3V modules but using the ESP's 3.3V to run some HCVAC system.
Try drawing your schematic on paper, take a picture of the drawing and post the image.
Untill I find my phone I'll describe... cuase my damn HVAC system is dead. F'n FUSE is intact, too. Lotta good that did. It gets power, the little LED goes on, but thermostat connections are dead. I'm thinking something must of shorted, with the ESP being male terminated and everything. I wire tied it to this circuit.
The Red HVAC Rh wire goes to one ~ leg of the Bridge rectifier and to ~ common of 3 SSRs. The Blue C wire goes to the other ~ leg, which is also connected to ground. (Is this a mistake?)
The + from bridge goes directly to the Input of L7805. The L7805 has it's ground to ground. The Output is to the ESP, Capacitor +. The ESP powers the 3 SSRs with a LLC as the LLC doesn't seem to like 3.3v.
I don't understand why BOTH the ESP and my HVAC blew. It seems to reason one would go, not both.
Until I find my phone I'll describe
That's up to you of course, but you are asking for help and to get help people need to understand what you have and what you did, and I for one can't understand your description so cannot help. Maybe others can.
I'm sorry to you. Had wife call phone. Now I have pictures. I'll attach them... first attachment done.
Second pic done. Schematic. Very roughly drawn.
Now here is bottom, again with traces highlighted and wires marked.
Second pic done. Schematic. Very roughly drawn.
Rough yes, but still a lot better.
You have a bridge rectifier on the left, you appear to have shorted out the -Ve output to the right hand AC input, that alone will cause a great deal of problems.
Where does the AC input come from? It might be on there but I can't make sense of it.
What voltage is the AC?
You need a capacitor on the input to the 7805 as well as on the output.
I don't understand at all the connections to the SSRA (SSRA? Solid State Relay A?)
By your own admission, the drawing is rough, so spend a bit of time making one that's neat. A ruler would help, as would a pencil and rubber.
With traces highlighted and wires marked.
You don't need to highlight traces, you need to draw neatly. If it's neat it doesn't need highlighting, if it needs highlighting it's not fit for us to see.
The ESP 3.3V connections to the HVAC, does the HVAC operate on 3.3V? Does the HVAC send voltages to the ESP32 GPIO pins greater than 3.3V?
Idahowalker:
The ESP 3.3V connections to the HVAC, does the HVAC operate on 3.3V? Does the HVAC send voltages to the ESP32 GPIO pins greater than 3.3V?
No. It ops on 28VAC on the RH wire, which when connected to G W or Y it turns that system on. The SSR is solid state relay. It is operated by 5vdc from the logic level shifter, that gets it's input from the. ESP.
PerryBebbington:
Rough yes, but still a lot better.
You have a bridge rectifier on the left, you appear to have shorted out the -Ve output to the right hand AC input, that alone will cause a great deal of problems.
Where does the AC input come from? It might be on there but I can't make sense of it.
What voltage is the AC?
You need a capacitor on the input to the 7805 as well as on the output.
I don't understand at all the connections to the SSRA (SSRA? Solid State Relay A?)
By your own admission, the drawing is rough, so spend a bit of time making one that's neat. A ruler would help, as would a pencil and rubber.
AC is present on HVAC RH line. 28Vac
Ok, so how do I obtain a ground? Just keep the C wire (earth) on other ac leg?
What size caps do you recommend for I and O of 7805?
SSR is hooked up as: AC1 = RH, AC2 = G, - = Gnd, + = ESP OUTPUT via LLC.
Ok, so how do I obtain a ground? Just keep the C wire (earth) on other ac leg?
If you want to ground the DC side then the AC side cannot be grounded, it MUST be floating. If you want to use AC through a bride rectifier to power the control system then you ground the DC side and control the AC side through a device that isolates the control side from the AC side. A relay will do this as will a SSR that specifically states in the specification that it provides isolation. If the source of the AC is not floating and cannot be made to float then you need a different source of power, or you need to keep the DC side floating, which brings its own problems.
It ops on 28VAC
28VAC after a bridge rectifier will be around 40VDC. A quick look at the specification for a 7805 shows a maximum input voltage of 30V. You now have 2 things that will damage components, the short on the rectifier and the high input voltage to the 7805.
SSR is hooked up as: AC1 = RH, AC2 = G, - = Gnd, + = ESP OUTPUT via LLC.
I refer you to my previous comments about providing a schematic.
TomGeorge:
Hi,
OPs schematic.
Tom... 
Thanks TG. I can see a bridge rectifier with diodes, and no output capacitor on the output of the bridge rectifier.
One of the diodes of the bridge rectifier appear to be short-circuited too.
I never saw anything near 40VDC... but i had shorted the ~ and - of bridge. I guess there is no easy way to power the module off the HVAC system. Ground is a problem clearly, and so is voltage.... I'll just run over a USB charger... that is currently what is being done. It looks messier and can be unplugged too easily but it did work. My schematic had flaws which we discussed, I don't have much investment in redoining them with a scematic program or with rulers, etc as my HVAC system has come back to life. I only wish my ESP32 did. Don't have a lot of money, those things are precious.
I'm not using the SSRs too... going back to traditional relay modules. The SSRs are only good at switching AC loads at 75V to 220V or so. I asked on the amazon site which I bought them, one person misinterpreted ?, one said they would switch 24V (I lowballed V in ?), the other said it wouldn't.... hmm... I may take a chance. 4x relay module is huge, what's stupid is it's only switching yet another relay on the HVAC board - the one that actually switches the furnace fan on and sends signal to ignition module... yet ANOTHER relay for the AC... lol.
Thanks much for your time.
Southpark:
Thanks TG. I can see a bridge rectifier with diodes, and no output capacitor on the output of the bridge rectifier.
One of the diodes of the bridge rectifier appear to be short-circuited too.
I did by mistake short the bridge.
There IS a capacitor.
Point is mute. Too complex trying to power one - darn.
mattlogue:
There IS a capacitor.
I see! That capacitor was left out --- doesn't appear in your original drawing, right?
