RT-1070 New 1070 temp getting higher then back itself down

[NickSno]

Hey all - just completed the burn-in and first cook on my 1070. Literally out of the box 2 days. Question for the group, when preheating the smoker, whether setting it to 250 or 400 Fahrenheit, it is typically getting above the preset temperature by 15 to 20° and then backing itself down to the desired preset temperature. Is this normal?

 

[Gonefishin]

Yes, your home oven does the same.

 

[SmokeOCD]

Swings get smaller over time. Quit staring at the temps.

 

[C. Keeper]

Not to mention, staring isn't polite

 

[NickSno]

Thanks all, appreciate it.

 

[Ruslan124]

Hey all - just completed the burn-in and first cook on my 1070. Literally out of the box 2 days. Question for the group, when preheating the smoker, whether setting it to 250 or 400 Fahrenheit, it is typically getting above the preset temperature by 15 to 20° and then backing itself down to the desired preset temperature. Is this normal?

What do you have set as the minimum fee rate? You could experiment with turning it down.

 

[SmokeOCD]

What do you have set as the minimum fee rate? You could experiment with turning it down.

Nope. That's mostly for preventing flameouts on Lo. Give the grill a few cooks before you goof around with settings. Do thighs, pork shoulder, burgers, hotdogs - cheap things that won't matter or make you cry if they're a little overdone. It should get better on it's own.

 

[Ruslan124]

A response I posted on a similar thread today. Note that it relates to wide and repetitive temp swings. If you climb high on initial start and it settles down after that, it is normal.

I had identical issues after upgrading my rt680 to the 3 RPM Auger motor.

The symptoms of wide temperature swings are directly related to minimum feed rate. If you set it too high, the auger dumps too many pellets into the pot and causes a large rise in Temps (as much as 100 degrees above for me) because it has lots of fuel in the pot. Only when the pellets have been mostly burnt does the temperature fall. Typically it will fall below the set temp (20 to 30 degrees for me) before more pellets are dumped and the cycle is repeated.

It appears that because it drops by 30 ish degrees it dumps even more pellets Because the gap to the set temp is reasonably large. I.e. per suport, the controller will use the minimum feed rate to make small temp increases. It uses a larger rate when closing a larger gap. Watch what happens when you set max temp to see what i mean. Listen to the fan on the auger to get a sense of how long the auger is running each time it kicks in.

The secret is to find the lowest setting for the Auger that does not result in a burn out. Once you find it you will only need to change it if the temperature outside has a large swing.

I had it set at 10 and it still didn't help, Today I spoke with support and found out it was possible to set 5 (I couldn't go lower than 10 in the app). Once set at 5 it performed flawlessly.

This setting however is also related to the speed of the auger, obviosly 3 rpm dumps more pellets every minute the auger turns than the 1.6 rpm originally installed. The higher the rpm the lower the minimum feed rate you need.

Again this information came from support.

Results, initial set temp is reached within plus 2 or 3 degrees. Temp drops when cooking are less than 10 degrees before adjusting back to set point.

P.S. I thought I heard support say there was an internall setting related to the auger 3 RPM. It would make sense but I am not 100% sure

 

[Ruslan124]

Nope. That's mostly for preventing flameouts on Lo. Give the grill a few cooks before you goof around with settings. Do thighs, pork shoulder, burgers, hotdogs - cheap things that won't matter or make you cry if they're a little overdone. It should get better on it's own.

I respectfully disagree. The auger turns at a fixed speed. The only way the temperature can be controlled is by turning on and off the auger.. The time it is on depends on the gap between actual and set temps.

The algorithm in the controller determines how that is done. If you set the minimum feed rate high for example 50, this is the minimum rate at which pellets are fed into the auger. You get way more pellets fed than if it is set at 10. Consequently if it is set too high, minor temp control is difficult and it can and will overshoot by a large amount.

Once the pellets are in the pot they can't be turned down, they have to burn (obviously). Once the temp starts falling after the pellets in the pot are burnt through and you reach set temp,(actually likely a few degrees below, you only want a few pellets to maintain the temp. A minimum feed rate if fifty results in way too many pellets and a huge climb in temp. This is the second reason you want your minimum feed rate as low as possible.

Listen to the auger and you will hear that it varies the time it is turning depending on the difference between actual and set times. Put it on max and it turns continuously. Put it on less than max and it will stay on a long time until it gets closer to set temp when it will turn on and off more frequently. It is the only way the controller can control the temp in small increments.

It is true a smaller rate allows a lower temperature. When set on low it uses the minimum feed rate only and it only feeds a few pellets at a time assuming feed rate is at a low number. It also has to be at a setting that balances low temp with the chance of a flameout.

 

[Gonefishin]

Sounds like you need set it high enough to prevent flameouts while maintaining a decent low temp, and low enough to minimize over runs.

 

[SmokeOCD]

I can see how minimum feed rate could be used for the small bumps, say to keep the grill cranking along when it falls below set temp. @Ruslan124 makes a logical argument, I admit I don’t know enough about the controller to say it is or isn’t so.
The OP is a 1070, I know it gets better a few cooks in, my setting, which is factory, is in my sig.

 

[Greg Jones]

Yes, your home oven does the same.

Not just ovens, but glass top and induction burners do the same thing. I have a $1,500 Control Freak induction burner, and it has slow, medium, and fast warm-up setting so that the user can choose and not burn a delicate sauce because it overshoots the target temp.

 

[okie]

Overshoot when arriving at selected temp and then drifting down to selected temp is common. The amount of overshoot varies depending on setting, weather, and probably other variables but is of no consequence. It you are quick to place the meat on the grates and close the lid, the temp will still drift down. If you fiddle around with the lid open, it will shoot up again, since the PID will sense heat loss and try to compensate. All of no consequence on a long cook as the discrepancy is short lived. On short hot cooks, I just wait for the temp to drift down to set temp and then quickly place the meat on and close lid. A good idea since the additional wait time allows all that metal and grates to also reach the same temp as RTD. (So you get good grill marks!). The only time I have adjusted was after several uses to make sure the control temp was accurate. I have left feed rate at factory setting. My adjusted temp readout is at 7+ which gives me great accuracy when set at 225*-275*.