New Pit Boss blue egg smoker - need to get adapter to mount Micro Damper

[RKHanso]

I put some more insulation around the top vent to seal it up a bit more around the large opening in the lid. But, those stock adjustable vent holes are not super-tight, even when they're closed. It would be nice to be able to improve those seals (which I understand do get better once grease/gunk builds up on them) - or buy an improved top vent - maybe something like THIS.

I suspect that the plate I made to mount the RD3 (the same one seen in the second post of this thread - made out of aluminum) is leaking. I've taped the edges of it up with some foil duct tape in hopes of sealing that better.

 

[Steve_M]

I didn't have any HM probs with the vent on my kamado joe, but I did replace it with the smokeware vent for the simple fact that it stays in position when lifting the lid and lowering the lid.

 

[RKHanso]

I didn't have any HM probs with the vent on my kamado joe, but I did replace it with the smokeware vent for the simple fact that it stays in position when lifting the lid and lowering the lid.

Steve_M - What blower are you using with your Kamado Joe? What size is it? What are your PID settings and other related settings for when the blower comes on, at what speed, etc?
My Costco Pit Boss is about 21" wide. I would guess our settings might be the same if we have similar sized kamados.

I saw on the PID tuning web page that someone with a BGE had these settings:
1. Large BGE
B: 0
P: 2.5
I: 0.0035
D: 6

Min fan: 10%
Max fan 40%
servo: on/off


but the exhaust vent was open way more on his than I have on mine.......so.....I opened up my exhaust (from being nearly completely closed off) and will see if it runs better.

 

[RKHanso]

It's looking a little better.
I have the top exhaust vent open to the .5 mark -- half way between closed and #1

and the graph and PID settings:

 

[RKHanso]

Here's a graph of the entire test below.

It looks like I ran out of fuel about 9pm since it couldn't get up to 425F - but for sure ran out at midnight.

Any tweaks I can do - or different settings or vent positions that will improve temps?

It seems I have a hard time maintaining steady low temps about 225F.

 

[Matt Fine]

Sorry I have been away a bit. I use a RD3 with a Pit Boss with very good results so let me get my setting for you.

 

[Matt Fine]

OK, logged in to my HM...

First, the servo and fan settings. I have the servo open the damper from full closed to full open between 0%-90% PID output. From 90% to 100%, the damper stays full open and the fan comes on. Fan minimum is 5% up to 50% max in run mode and 100% at startup.

I can't upload a pic at the moment but the settings look like this:

Fan output = Voltage on above = 90% min 5% max 50% startup max 100%
Servo pulse duration xxx us - yyyy us, fully open at 90%

The xxx and YYY will be whatever you need for your servo and damper to be full open and full closed.

For PID, I have been messing around with them lately, but my current settings which work well enough for a start are P= 10, I= 0.0035, and D = 1.5

I run the top vent just a bit more open than your photo, but if all else is working, it is not that sensitive to small changes in the top damper. Figer each slit about 1/16"-1/8" open for low temps, more as you go higher in set point.

 

[RKHanso]

thanks for that info Matt.
I made a turkey on my grill yesterday and the temps did end up being pretty steady. I forgot to get a screenshot before powering it off and didn't save the cook in the logs.

My settings are:

Yours are quite a bit different. Maybe there's a lot of fudge-factor available in these settings? The Heatermeter was designed TOO good?

I'll try your settings next time and compare the results.

 

[Matt Fine]

There are definitely many setting combos that will work. I do see a couple things I think you should change and a couple you should consider changing.

On your fan settings, you have the min set to 0 but many blowers will not like very low settings. I would suggest setting the min to 5%. You also have the startup max lower than the operating max. I would switch the two of those so that it is a max of 50% when running but you have 100% on startup to get up to temp quicker for your hotter cooks.

The things you might want to consider changing are when the servo is full open and when the fan kicks on. You currently have the fan coming on at only 12% when the servo is barely open. Why make the fan try to pull air through a small opening, and also, why use the fan at all there when the servo can open a lot more? I would suggest upping the “on above” setting from 12% to at least 75%. I have been using 90% which has been working well. The Pit Boss doesn’t usually need any fan for small adjustments, just when you are changing set points, need to recover, or for high heat settings.

Along those lines, I would set the servo “fully open at” number to whatever your fan “on above” number is. That way, as the HM is calling for more heat, it will open the servo more and more, and once the servo is fully open, if it wants more air flow, it will start to ramp up the fan. Your fan won’t run nearly as often, and when it does it won’t have work as hard to fight a partially closed damper.

Your PID setting will probably work OK. I increased the P on mine because when it was lower the temp would get close to target but never quite hit it. You can play around with those or checkout the guide to PID tuning that is on the GitHub or somewhere like that.

 

[Michael Werner]

I’d be very curious if others are getting better results with lump(and you are using lump in your pit boss, aren’t you?) in a kamado. I just wouldn’t expect a dead flat temp curve out of a natural material with the incredible size variations of lump. I’d be happy as a clam with your last graph.

 

[Matt Fine]

I’d be very curious if others are getting better results with lump(and you are using lump in your pit boss, aren’t you?) in a kamado. I just wouldn’t expect a dead flat temp curve out of a natural material with the incredible size variations of lump. I’d be happy as a clam with your last graph.

I get very consistent burns with lump. The fire is air limited so the shape variation doesn’t have much impact except when running wide open.

 

[Gary V]

RK,
here are my setting for a tightly sealed ceramic grill. I currently use an Adapt A Damper. These should work with some fine tuning for the RD3. The Micro-Damper will not control well on my grill with these settings. I have to make changes mainly to the fan side of things since a blower is a pressure type device and a fan is a cfm type of device.

P = 2.8
I = 0.0035
D = 6
Fan Output = Voltage
On Above = 0%
% min = 0
% max = 30
% startup max = 65

Next item is make sure your thermocouple is not clipped to the grill grates. On my grill, I drop the thermocouple down through one of the dome damper slots and dangle it as close to the center of the dome as I can. I still have a top damper open around a 1/8" depending on the temp I am controlling too. Make sure you have no air leaks. Air leaks are bad. Close the grill with a dollar bill between the gaskets and pull. Must have drag. If not you have a leak. Check all around the grill. Make sure you do not leaks around your inlet damper. Most grills will have a seal of RTV between the inlet damper assembly and ceramic shell. If no seal or it is damaged, fix.

 

[RKHanso]

Started a couple pork butts from Costco.

I ran the pit temp probe though the top vent and then closed it as far as I could. Even then, that's open too far and the temps have a hard time dropping, so I put some foil tape over 4 of the openings to close it off even more. It's been more stable after that.

Active grill going HERE

Current settings:

 

[Gary V]

since your using a ceramic grill, the pid numbers for most of the ceramic grills out there will have close, if not the same numbers, for any ceramic grill. The P value should be somewhere around 2.5. I, should be somewhere around .0035. Anything higher will make the oscillation from the high gain you currently have set, to happen faster and the swing can be larger. D should be around 5-6. Unfortunately I did not have the best control with the microdamper so I went with the adapt-a-damper which has worked well for me. Tightly sealed ceramic grills work better with blower based dampers. I recently have built a Tom Kole offset damper and the barrel damper on the first page of his sticky post . These work well and I have been currently using the first design, the barrel damper, because the physical design and flow characteristics really match the flow needs for my Primo Jr. With any off the dampers, I keep my pit probe in the center of the dome around the same level as the mechanical probe and the dome vent slightly cracked. One other thing is I use ceramic plates when I cook using my primo jr. This keeps the temp fluctuations from the direct flame from effecting the control. Nice steady temps.

 

[John_Matthews]

So, just seeing this - I've got the PitBoss in black from a couple of years ago - essentially the same grill.

I'm using the HM with a MicroDamper, very successfully. My attach is similar to everybody else: construct a metal piece to cover the door opening with a home in it. Then I've soldered on a copper pipe->threaded adapter and then use a PVC threaded that is glued to the MicroDamper. I leave the plate/copper on the grill and then have a PVC threaded cap to screw on to close up the opening if needed.

I saw somewhere in the above, the pit probe was coming in through the top - I don't do that...... just let the pit probe cable get sandwiched between the egg halves. It'll seal up OK.

In terms of settings, I've tried various and it's pretty tolerant. My current are:
- P=1.5, I=0.0035, D=6
- Servo fully open at 50%
- Fan = Pulse on at 50%, min 10%, max 100%, startup 100%

You will only need the top open at about 0.5, possibly a bit less. If you want to get started faster, open all the way (but remember to close it).

Today is a smaller brisket...... well controlled.

EDIT: The MD is really damn good for low control. I too have struggled to get the MD to get to high temps (600+). It can do it but only if it's new lump and the firebox is full. Usually, I'm topping out at about the 400 degrees level under usual (old lump, firebox not full) circumstances. I printed and made a bigger blower but have yet to test if that can get me to the higher temps a little more easily.

Cheers,

John