Bull Temp drops off for no reason during a cook?!?

[Kws148]

I have a 700 and I was doing a cook this evening and after I turned the temp up from 400 to 475 the temp just started dropping. Anyone have any experience or idea why this would occur? I’m using dry recteq brand pellets and the temp outside was about 34°F. I don’t understand why it would just start dropping temp when I increase the set point. Pellet hopper was filled before the cook started. Also is it normal for it to take an hour to reach 400 in 34°F with slight wind?

 

[Newb]

- Look for bridging of the pellets. If the hopper looks full, but the pellets can’t drop into the auger, then that could be a problem.
- Is the temp probe loose or bent and touching the side wall of the cook chamber?
I’m sure others will have some ideas too.

 

[Kws148]

- Look for bridging of the pellets. If the hopper looks full, but the pellets can’t drop into the auger, then that could be a problem.
- Is the temp probe loose or bent and touching the side wall of the cook chamber?
I’m sure others will have some ideas too.

Temp probe isn’t bent but,I could try stirring up the pellets in the hopper to break up any bridging that might have developed. Thanks.

 

[sdynak]

How old if your Bull and has it been used a lot to compare past performance? An hour for 400 is not good even with wind and 34 degrees. Something is not right.. you can also remove the diffuser and watch what i happening such as the auger feeding pellets.. At 400 I would expect pretty consistent dropping of pellets. I would call Recteq if the above does not work out or if something does not come out from watching the burn.

 

[Kws148]

How old if your Bull and has it been used a lot to compare past performance? An hour for 400 is not good even with wind and 34 degrees. Something is not right.. you can also remove the diffuser and watch what i happening such as the auger feeding pellets.. At 400 I would expect pretty consistent dropping of pellets. I would call Recteq if the above does not work out or if something does not come out from watching the burn.

Thanks for the input. My bull is maybe 7-8 months old. I’ve only used it say 8 times so far. I was attempting to do chicken thighs 0-400 method then turn the heat up and sear the chicken thighs on my sear plates. I’ll pull the diffuser tomorrow and see if I notice anything out of the ordinary. I don’t have much experience with pellet grills but I thought an hour was a long time to reach 400. I may end up calling customer service tomorrow and see what they have to say.

 

[sdynak]

Yeah make sure all is clear and the fan is strong and pellets dumping. Might be something obvious and if not give them a ring. Sure they will get you hooked up like new.

 

[Jim6820]

You have received good advice above. While I don‘t have a 700, I’d have to say that your experience is not normal. My smaller RT-340 will get well above 400 degrees in freezing temps with a stiff breeze blowing. It will consume a bunch of pellets doing so, but it will do it.

A couple of additional questions. First, how do you store your pellets? And, has your hopper had pellets in it for a while without being used. Is it possible that the pellets have absorbed moisture and are not burning properly?

And, how long has it been since you cleaned the ash out of the fire pot and belly of the beast? Too much ash in and around the fire pot will suffocate the fire.

As has been said, once you’ve checked the obvious possibilities, give Recteq a call. One of their reps will walk you through some diagnostics and almost certainly identify the issue.

Good luck.

 

[Kws148]

Update…
I pulled everything out of the grill and cleaned out the burn pot. This has been the first cleaning of the burn pot so I was thinking this may have been the culprit. I ran the grill without the diffuser so I could see what was happening. Everything seems to be operating fine. I’ve attached the temp graph so you guys can see what I’m talking about. The temp starts climbing and then out of the blue just starts dropping. I opened the lid 3 different times to see what was going on and all looked normal, fan running, auger turning and pellet’s emptying into the burn pot. At one point the temp went from 400 down to 360. I opened the lid to see if the fire was out and the auger was turning and pellets dropping into the burn pot with I never fire in the pot. Then a little later the temp swung in the other direction to 414°. At this point I’m thinking the temp probe may be at fault. I put everything back together and I’m trying another test run with my 2 probes inside the grill also. It’s 41° outside with no wind so that shouldn’t be a problem with the temp swings I wouldn’t think.

My pellets are stored in my garage on some shelving. They were bought back in July I want to say. Maybe that’s part of the problem also. They are all dry but who knows how much moisture they could have picked up from sitting for that long a time.

More to come….

 

[sdynak]

Update…
I pulled everything out of the grill and cleaned out the burn pot. This has been the first cleaning of the burn pot so I was thinking this may have been the culprit. I ran the grill without the diffuser so I could see what was happening. Everything seems to be operating fine. I’ve attached the temp graph so you guys can see what I’m talking about. The temp starts climbing and then out of the blue just starts dropping. I opened the lid 3 different times to see what was going on and all looked normal, fan running, auger turning and pellet’s emptying into the burn pot. At one point the temp went from 400 down to 360. I opened the lid to see if the fire was out and the auger was turning and pellets dropping into the burn pot with I never fire in the pot. Then a little later the temp swung in the other direction to 414°. At this point I’m thinking the temp probe may be at fault. I put everything back together and I’m trying another test run with my 2 probes inside the grill also. It’s 41° outside with no wind so that shouldn’t be a problem with the temp swings I wouldn’t think.

My pellets are stored in my garage on some shelving. They were bought back in July I want to say. Maybe that’s part of the problem also. They are all dry but who knows how much moisture they could have picked up from sitting for that long a time.

More to come….

I think you are on to something.. double check the RTD wires and make sure nothing is pinched and all is connected well at the controller. I'd say from those swings it is likely too quick to be true and likely you are finding your issue with the RTD. The probes are a good idea to compare.

 

[Kws148]

So now I’m really confused . I turned the grill back on and set it to 400 and it took 46 minutes to reach temp. The grill was just on so it was already 82 inside the grill. The probes I just put in so you will see the temps are lower then the actual grill temp at the start. But now I have no idea which temperature is correct. I’m getting 3 very different readings. The temp maintained 400 after it hit it but it took awhile. Then I raised the temp up to full and it only ever got to 437. I’d say something is not right. I’m going to make a call with customer service. I checked the RTD wires for the main temp probe installed in the grill and other than a little ash on the wires they look fine. Once the grill cools down I’ll give it a more thorough going over. What do you guys make of this??

 

[sdynak]

Wow.. kinda all over the place. Hard to say unless you have something you can trust like a separate temp sensor all together. At this point just see what they say. No doubt you have an issue. At least you have a good idea on the nuts and bolts of the operating.

Maybe someone else will have a view until Recteq and provide guidance. Only thought I have aside from wasting time is another known good temp measuring source without swapping parts.

 

[Kws148]

Well I moved my sear plates to the center of the grill and ran another test and the results were more in line with what I was experiencing before. The probes were for the most part consistent with the grill RTD. Once I turned it up past 400 to full the temp climbed to 467 before falling off to 437 within the next 20 minutes. It still took 40 minutes to get to 400 and the grill was still warm 118° from the last test. I’m not sure what to make of it other than possibly pellets, but that doesn’t explain the temp drop with my cook last night and todays test. I had the other probes in to verify temps that the grill was indeed cooling down.

 

[Jim6820]

This is precisely why I have an independent heat measuring device; it eliminates the variable of the Recteq probes being inaccurate. My choice was a ThermoWorks Signal 4-channel unit. It comes with a probe/clip combo designed to measure grill temp, along with three meat probes. There are certainly other choices, but an independent test capability is essential in my view.

My best guess is that you have a failing control board. You’ve done enough diagnosis and testing to convince me of that. A call to Recteq is in order.

 

[Waterboy]

I’d suggest you remove the sear plates completely then see what you get. You absolutely don’t want them on the left side of the grill as they will totally mess up the RTD readings. Go with stock grates only and see how the grill works. If things work right then add sear plates to the right side of the grill.

 

[MorllEySwenseL]

Friend, I had such problems, but a familiar master helped me

 

[Simarti28]

This happened to me before. My pellets were the problem (recteq brand). I bought them from Amazon so who knows how old they were. They didn’t look or feel wet. Called recteq and they said to try a fresh bag of pellets. Problem solved.

 

[floridaambient]

This happened to me before. My pellets were the problem (recteq brand). I bought them from Amazon so who knows how old they were. They didn’t look or feel wet. Called recteq and they said to try a fresh bag of pellets. Problem solved.

Wet or even damp pellets will make the burn pot form a puck in the bottom. This can cover the air holes and also the igniter and your brisket will hate you. The fire pot is your life, keep it clean!

 

[kstone113]

Reading everything above, I would vacuum out all the pellets you can and put a new bag of pellets in and see how it goes.....sometimes it can be pellets even though they seem fine looking at them.

 

[Kws148]

I appreciate everyone’s help. I called customer service and over the course of a few days of emails and phone calls we got to the bottom of it. Ultimately what we found was that my RTD was positioned to close to the side of the grill. Mine was 1/2” from the side and they had me move it so that it was 3/4” from the side. Fired up the grill for an hour and I was able to achieve and maintain 540°. This was in 29° weather with questionable pellets. The pellets were rectec ultimate blend that were purchased from Amazon as a gift from my mother-in-law. So who knows how old they actually are. My sear plates were originally on the left side which was causing my temps to drop randomly. Something else I learned was that an RTD can only fail at its max or min temp reading. When they fail they fail, they don’t start to drift in temp like I originally thought. Hopefully this can help someone else out who ends up having these kinds of issues.

 

[Jim6820]

Thanks for following through with the update. This information will surely be helpful to other folks down the line. Glad you got to the bottom of the problem.