Masterbuilt 560 won't hold temp?

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jr.s

Fire Starter
Original poster
Dec 4, 2006
46
12
Have had a Masterbuilt 560 for exactly a year today. Noticed recently that it wouldn't heat up beyond 450 or 500. Opened a ticket with Masterbuilt and started jumping thru the hoops to try and get it fixed before the warranty ran out. "Does the fan run?" "Hook the fan directly to the controller.", and so forth and so on, for a couple of weeks. Finally the last thing I tried was some troubleshooting of my own. I bypassed all 3 door switches. It promptly fired up to 612! But once I started grilling, it quickly dropped. By the time I was done, it was down to 350. I left it running while we ate just to see if it would jump back to 600, closed up tight. Wouldn't move off of 350.

To me, everything has been eliminated except the fan is not running fast enough, or the controller is not telling the fan to run faster. What was the solution at Masterbuilt, you ask? "We've ordered you new door switches." You have got to be kidding me. That's not the issue, I think we've proven that.

Am I wrong? Shouldn't it run just fine with the door switches bypassed?

Anybody else see this? And what was the ultimate solution?
 
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Definitely sounds like a switch issue and surprised the bypass didn't work.
I also cut mine loose and have had no issues.
Frien did have his temp probe go bad and it wouldn't come up to temp.
$8 replacement from Amazon and 5 minutes work and he was up and running.

Keith
 
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Sounds like a temp probe issue to me. Is there any way to test the temp probe separately? Like can you turn the unit on but not start it and put the probe in ice water or boiling water to verify the readout?
 
Sounds like a temp probe issue to me. Is there any way to test the temp probe separately? Like can you turn the unit on but not start it and put the probe in ice water or boiling water to verify the readout?
Might be a possibility just 1 screw holding it in place but the cable is short.
I believe the controller only goes down to °140. Might just order one and try it.
I got mine overnight shipping.

K
 
Sounds like a temp probe issue to me. Is there any way to test the temp probe separately? Like can you turn the unit on but not start it and put the probe in ice water or boiling water to verify the readout?
I assume temp probe is the probe that tells the controller when it's at temp? Not the food temp probe?
 
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I assume temp probe is the probe that tells the controller when it's at temp? Not the food temp probe?
Yes, that would be the one. I just don't know where its located or if it can be removed but still connected. I would try to verify in an ice water bath and boiling water (or close to).
 
However, there may be a problem testing that probe.

Its been speculated here, that the controller is calibrated to adjust for a difference in temp from the far left side of the cook chamber and the middle of the lower grate.
 
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It may be hard to get to, but I'd check the connections to the inside temp probe. If there's too much resistance there, the controller will interpret it as a higher temp so the controller may think it's 600F when it's only 350F. Replacing the probe (may be nothing wrong with it) won't help if the corrosion/grease is on the mating parts. Make sure all connections are bright and shiny.
 
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