Ambex YM-10 Oddities

[kjhibbs]

We have been roasting for a while on our YM-10 for awhile and all has been good on our curves. We are using Cropster to monitor both exhaust and bean mass temps. About a month back we finally got our machine hard plumbed to propane and off of bottles and shortly after started having some issues.

For a given roast we will heat up our charge temp, drop the beans, at the turn we will crank up temp and things will go smoothly until around the 7 minute mark or so and the exhaust temperature will start dropping out. I have attached an example of this. From that point I have to constantly adjust airflow to try and keep the exhaust rise close to my profile. When things were "normal" whatever trajectory the exhaust temp was set on would continue until adjustments were made.

Thinking it was the switch to the plumbed propane line we switched back to tanks and the issue was the same. Any ideas or direction would be super appreciated.

 

[Musicphan]

What is the bean temp when this occurs?

 

[kjhibbs]

Right around 300 degrees.

 

[kjhibbs]

Here is another example with the bean mass curve in blue.

 

[museocoffeeco]

where is your exhaust temp probe located? after the motor in the first section of chimney? what airflow adjustments are you making?