Heatermeter Fan Issue..


 
W

WilburBurns

New member
OK, it's been a while since I had messed with my heatermeter, mainly because I was pretty frustrated and could not get it working or even monitoring temps correctly. That being said, today I had some time at home with an empty stove and decided to do some testing.

So, what I determined is I still have a few problems. Not a surprise, because I was having trouble the last time I tried to use it on my Egg.

I have a meat probe that is only "Close" to correct some of the time, other times, it's hundreds of degrees off. Bottom line, I'm saying that's just a bad probe. I've had a lot of bad probes, and this is getting frustrating though to keep replacing them.

Next problem is the Fan. I'm using a roto style damper with a fan. When testing this afternoon, no matter what I did, the fan would not come on. The damper would open and close appropriately, but the fan would not come on. Finally, I ran out of time, shut off the oven, and had to go out for a while.

Fast forward to about 10 minutes ago. I open the Kitchen door, and hear an odd noise. I had left the heatermeter plugged in and just left earlier. Therefore, the damper is open completely, and the fan is running full speed. Again Odd, because I could not even force it to come on earlier.

So, obviously, time to test some more. I set the Pit "Set Temp" to 160 degrees and turn on the oven to 200 degrees and just watch.

As the Oven temp rises, the damper closes as expected. The temps rise to 160 and keep climbing to 215 according to the heatermeter, but here's the problem. The fan is still running. It hasn't shut off yet.

So, what is wrong? I just don't get it.

Here are my PID output parameters
Proportional 2.5
Integral 0.0035
Derivative 6

Fan Output - Voltage
On above 10%
Min 40%
Max 90%
Startup Max 90%
Invert output - unchecked

Servo Pulse duration 850 - 1750
fully open at 100%
invert output - unchecked

A/C input noise filter - OFF

This is really frustrating me and it's grilling season, I really want to connect this to the egg and let her maintain temps, no matter what temp I need, but right now, I have zero confidence in how it will work.

Cliff
 
I am not an expert with the PID settings, and I'm sure others will chime in, but I would try changing the MIN setting from 40 to 0.
 
To eliminate frustration I suggest you adjust your fan settings a bit, at least until you have everything locked down and working properly.
Set your fan to
Pulse Mode
On Above 0%
Min 0%
Max 100%
Startup Max 100%

Set like this you should see your fan and servo ramp from 0-100% together directly as the HM output goes from 0-100%. Use your HM button to set Manual Fan mode, then use the button to sweep from 0-100% output. Does it follow, if so change the fan to Voltage Mode and do the same. Does it follow? If so everything seems to be working.
If not, then you have hardware issues. Check your CAT5 cable, connection at the fan, soldering around the MOSFET and surrounding components... but hopefully it will work properly

I would suggest you start with these settings, but drop the MAX setting down to match whatever works well with your grill and target temperature.
 
RalphTrimble said:
To eliminate frustration I suggest you adjust your fan settings a bit, at least until you have everything locked down and working properly.
Set your fan to
Pulse Mode
On Above 0%
Min 0%
Max 100%
Startup Max 100%

Set like this you should see your fan and servo ramp from 0-100% together directly as the HM output goes from 0-100%. Use your HM button to set Manual Fan mode, then use the button to sweep from 0-100% output. Does it follow, if so change the fan to Voltage Mode and do the same. Does it follow? If so everything seems to be working.
If not, then you have hardware issues. Check your CAT5 cable, connection at the fan, soldering around the MOSFET and surrounding components... but hopefully it will work properly

I would suggest you start with these settings, but drop the MAX setting down to match whatever works well with your grill and target temperature.
Click to expand...

OK, I tried this, but the fan still does not shut off and the damper is closed completely. I even tried resetting the heatermeter by pulling power and letting it reset, and by doing a full reboot from the menu.

For a bit more info, I'm running 4.3 and an early version of the firmware. No idea if that may be causing problem.

http://pehome.pewebhost.com:8081 will allow you to see the current probes, what you don't see is the fan running even though output is a 0%

Cliff
 
Are you using a thermocouple for pit probe "0"? If you are, make sure that you selected probe "0" in the config program to be thermocouple. If you are using a MicroDamper, make sure the connections in the plug and on the receptacle in the housing are not shorting. When I assembled my MicroDamper I had to bend the receptacle solder lugs toward the housing so I created plently of clearance between wires and servo. After that everything worked.
 
OK, now that you've verified that it's not software settings confusing you it's time to look at your hardware.
First thing you need to do is make sure things are wired correctly. Best way is (with power off) check continuity from the blower wires to the solder joints on the CAT5 jack marked BLOW and GND, and from the servo red to +5, orange to servo, brown to gnd. It's fairly common for a new build to have issues with the blower, but rare to hear someone say the servo is misbehaving as well, so I would look at your wiring first.
If all those connections check out the next thing would be to post some closeup pics of the board so forum members can take a look and perhaps spot your issue.
 
RalphTrimble said:
OK, now that you've verified that it's not software settings confusing you it's time to look at your hardware.
First thing you need to do is make sure things are wired correctly. Best way is (with power off) check continuity from the blower wires to the solder joints on the CAT5 jack marked BLOW and GND, and from the servo red to +5, orange to servo, brown to gnd. It's fairly common for a new build to have issues with the blower, but rare to hear someone say the servo is misbehaving as well, so I would look at your wiring first.
If all those connections check out the next thing would be to post some closeup pics of the board so forum members can take a look and perhaps spot your issue.
Click to expand...

I'm checking this now. That being said, I'm having a hard time believing it's not a software of control issue. The fan is obviously getting voltage on the line, otherwise, it would not turn on at all.

Cliff
 
If you want to confirm that it's not software, try this.

With the HM board disconnected from the RasPi, remove the ATMEGA 328P chip from the socket and then plug in the HM. If the fan still blows, it's a hardware problem.
 
Steve_M said:
If you want to confirm that it's not software, try this.

With the HM board disconnected from the RasPi, remove the ATMEGA 328P chip from the socket and then plug in the HM. If the fan still blows, it's a hardware problem.
Click to expand...

OK, this was an easy test. With everything in pieces, and only plugging power into the HM board, without the atmega chip, the fan comes on and stays on.

I'm attaching pics of my board.

IMG_2643.JPG


IMG_2644.JPG


IMG_2645.JPG


IMG_2646.JPG


Cliff
 
Cliff, Not sure if you tried mounting project in the box before you tested everything, you might want to check Q1 to see if the leads are shorted, broken, etc. When I finished prelim testing I went ahead and mounted into case. I had fan issues and Q1 was one of the problems. The heatermeter main board has very little clearance between the case tab and Q1. I damaged my FET and had to get a new one. Once repair was complete and boards tested I installed back in case very carefully once testing was finished. Another thing you might want to do is lay some electrical tape on top of the Ethernet and usb jacks of the Pi so incase boards make contact to jacks things do not fry.
 
Gary V said:
Cliff, Not sure if you tried mounting project in the box before you tested everything, you might want to check Q1 to see if the leads are shorted, broken, etc. When I finished prelim testing I went ahead and mounted into case. I had fan issues and Q1 was one of the problems. The heatermeter main board has very little clearance between the case tab and Q1. I damaged my FET and had to get a new one. Once repair was complete and boards tested I installed back in case very carefully once testing was finished. Another thing you might want to do is lay some electrical tape on top of the Ethernet and usb jacks of the Pi so incase boards make contact to jacks things do not fry.
Click to expand...

Good catch on the Q1 as it does appear as though it was bent out of shape, and one of the prongs broken. I'll get that fixed/replaced and try again.

Cliff
 
Cliff,
Glad I could help.
I noticed a couple things from your pictures. on the first picture there is a 2.2kohm resister mounted lengthwise on the board and its located by the diode mounted next to the power regulator in the upper right side. One the bottom the solder connection look like the solder needs to be reheated. Also you mentioned temp probes reading. I see that the 10k, blue body resistors precision resistors, for probes 3,2,and 1 look like they might need reheating as well. Cannot see any other things that come to mind. To help with solder joint checking I clean my boards with sudsy ammonia and a toothbrush. Then rinse with water. Then I give them a good drying with my compressor. make sure the ATMEGA 328P is removed before cleaning. Now when you look at the solder connections you have a fighting chance of seeing problems.
good luck.
 
WilburBurns said:
I'm checking this now. That being said, I'm having a hard time believing it's not a software of control issue. The fan is obviously getting voltage on the line, otherwise, it would not turn on at all.

Cliff
Click to expand...

Hard to believe it's not a hardware issue IMHO, there are so many hardware issues that could cause the fan to blow all the time. You could have the fan connected to the +5V wire instead of the Blow wire, fan will run continuously. You could have a short on Q1 or Q3 (solder bridge etc), fan would blow all the time etc etc. On the other hand, it is not impossible it could be a software issue, but that is extremely rare (like an incomplete flash of the ATMega), hardware issues on a new build are quite common though, particularly in the blower circuit.
 
Below are a couple images that might be helpful to troubleshoot the blower circuit.

HM_Blower_Notes_V4.3.jpg


HM_Blower_Notes.jpg


The top image is your v4.3 board, solder side, the green lines represent the connections made by traces that are on the other side of the board. As you can see, the blower circuit goes from the ATMega Pin5 to the center pin of Q1, then from the left pin of Q1 to the right pin of Q3. You can measure voltages as noted to see if your transistors are biased properly. You can verify the logic is working in the ATMega by removing it and installing so Pin5 is propped out of the socket, then measure voltage on the isolated Pin5, look for 0v when the HM is at 0% and 3.3v when the HM is at 100%. If you see Pin5 go from 0v to 3.3v you do not have a software issue, look further at the hardware.

The bottom image shows the complete blower circuit on a V4.2 board, including more notes about the feedback circuit etc. I didn't take the time to add those notes to the V4.3 image, but the components and circuit is the same, you'd have to locate them yourself to troubleshoot.
 
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