# Rec Tec RT-700 Bull.  Large temp fluctuations



## vaffanculo403 (Feb 17, 2019)

So my buddy just bought a used RT-700 Bull with a cold smoker box and when we plugged it in today it was acting a little strange.  I set the temp to 225° and everything looked good.  It hit 225° and the fan was cycling.  Next thing I know the temp dropped quickly to roughly 150° and then rose just as quickly back to 225° and it continued to cycle like that.  Given how fast the temp decreased and increased I'm thinking maybe it wasn't actually fluctuating and possibly the controller or the RTD probe is bad.  Has anyone experienced this?  Any thoughts would be appreciated.

Thanks


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## retfr8flyr (Feb 17, 2019)

I would give the Rec Tec guys a call. Even though you are not the original owner, I have heard they are great to work with.


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## CountyCop911 (Apr 10, 2019)

I just bought one and had similar temp problems.


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## SlowmotionQue (Apr 10, 2019)

How long have you had it CountyCop911?

Did it start acting up right away?


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## SlowmotionQue (Apr 10, 2019)

vaffanculo403 said:


> So my buddy just bought a used RT-700 Bull with a cold smoker box and when we plugged it in today it was acting a little strange.  I set the temp to 225° and everything looked good.  It hit 225° and the fan was cycling.  Next thing I know the temp dropped quickly to roughly 150° and then rose just as quickly back to 225° and it continued to cycle like that.  Given how fast the temp decreased and increased I'm thinking maybe it wasn't actually fluctuating and possibly the controller or the RTD probe is bad.  Has anyone experienced this?  Any thoughts would be appreciated.
> 
> Thanks



I’d definitely contact Rec Tec.

In the meantime, I’d check it against a reliable device like a Weber IGrill or Thermoworks Smoke.

That will let you know if the temp probe is bad.

Either way though, I’d contact them.


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## CountyCop911 (Apr 11, 2019)

SlowmotionQue said:


> How long have you had it CountyCop911?
> 
> Did it start acting up right away?



It started on the first use.  I saw it jump from 250 to 305 in the blink of an eye.  Then it went in to some sort of cooldown mode and was fan only for about 15 minutes.  Once it got down to setpoint, the fan would run for 5 seconds, then off for 5 seconds for maybe 30 minutes until I unplugged it for 10 minutes.  Had no idea what was going on and no where in the owners manual does it mention that behavior.  Rec-Tec said the RT-700 will do that and admitted it is never mentioned in their manuals.  Whether the temperature was actually over 300 and not reflected on the Display is still a mystery.


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## txgunlover (Apr 11, 2019)

Fan running on and off every few seconds is normal.


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## SlowmotionQue (Apr 11, 2019)

CountyCop911 said:


> It started on the first use.  I saw it jump from 250 to 305 in the blink of an eye.  Then it went in to some sort of cooldown mode and was fan only for about 15 minutes.  Once it got down to setpoint, the fan would run for 5 seconds, then off for 5 seconds for maybe 30 minutes until I unplugged it for 10 minutes.  Had no idea what was going on and no where in the owners manual does it mention that behavior.  Rec-Tec said the RT-700 will do that and admitted it is never mentioned in their manuals.  Whether the temperature was actually over 300 and not reflected on the Display is still a mystery.



Unplugging it was probably not a good idea.

I do believe though that they tell you in the manual not to unplug it to shut it down.

Temp likely would have leveled out on its own given time. 

I recall you mentioning temp swings of plus or minus 100*. Is my recollection regarding that accurate?

Did you get any error codes?


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## txgunlover (Apr 11, 2019)

The PID controller has to learn, you have to let it run.


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## SlowmotionQue (Apr 11, 2019)

One other thing I might add, if temps get out of control on either my WSM or my KJ, the quickest and most immediate way to eliminate heat inside those is to open the lid and let it escape.

I’m sure that this will work with a pellet grill as well.

But page 12 of the manual says; “never unplug your grill to turn it off...”


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## txgunlover (Apr 11, 2019)

Opening the lid will prevent the PID controller from adapting and you should not do so on a pellet grill in an overrun...  ESPECIALLY the first time running it for a cook.


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## SlowmotionQue (Apr 11, 2019)

txgunlover said:


> Opening the lid will prevent the PID controller from adapting and you should not do so on a pellet grill in an overrun...  ESPECIALLY the first time running it for a cook.



Scratch that idea then. 

I’ve only had to open mine in an attempt to cool things down  during my very initial attempts at using the Smokedaddy Heavy D diffuser a couple of months back, after the wood in it took flame and shot temps up to beyond what the PID controller could keep up with.


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## kstone113 (Oct 3, 2019)

https://www.smokingmeatforums.com/t...-burner-attachment.279194/page-8#post-2004469

Long thread about the Heavy D.  Short version - line the SDHD with foil, put in logs/chunks, poke holes in the foil and this should stabilize your temps.  It has worked numerous times for me and others.


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## kstone113 (Oct 3, 2019)

I apologize, I miss read the thread...someone did mention heavy d so I assumed that was the cause.

This is not normal at all.  If it is going up and down very fast....could be bad controller, bad temp probe....assuming this is very fast.  

Rec Tec CS can help you troubleshoot.  New controller is $199 :(


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