Quest M3 heating elements (alternative sources)

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
MarkG
Posts: 19
Joined: 17 years ago

#1: Post by MarkG »

Both elements on my Quest M3(2014) have died 3 days ago. I started to have suspicion about them a year ago and even got in contact with Molly but unfortunately decided to postpone buying spare ones. I wrote to Molly right away but since then - crickets, no reply and I'm starting to panic.
Does anyone can suggest any alternative sources for those elements and what exactly I should look like. Measurements I can take but what wattage is needed?

Nunas
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Joined: 9 years ago

#2: Post by Nunas »

That's a shame; I've had two Quests and both have been totally trouble free. I can't help you with a definite source, but have you tried Coffee Shrub? They claim to have been involved in the choice of heaters.
We did have trouble with the initial heating elements sent with the machines, but we worked with the manufacturer so now the heating elements have a higher electrical rating (up to 130v).
As for the electrical size, the heaters take nearly all the current. They are in parallel. So, if you look on the nomenclature plate of your roaster for the power (I don't remember what mine was, probably about 1100 Watts), divide by two, and you'll be about right. Or, if you remember how high the current meter went before the elements went out (probably about 9 Amps; 120*9=1080), each one would be about 540 Watts.

However, something is fishy here. You might want to have a close look at your electrical supply. It would be a shame to replace the heaters only to have them blow again. Usually, only one element dies at a time, and even that is relatively rare, except for a few of the original M3. For two to go out at once makes me suspect that your power utility is/was providing too high a voltage. Unless, of course, you were using a variable autotransformer (Variac) which was set too high. Another possibility is that you let it warm up way too hot. The Quests don't have any safety thermostats in them and will simply get hotter and hotter if left unattended, especially with low or no fan.

If you find a source, please post it here for future reference. When I finally get around to reediting the Quest Handbook, I'll include the source.

MarkG (original poster)
Posts: 19
Joined: 17 years ago

#3: Post by MarkG (original poster) »

Update on my quest for Quest M3 heating elements:
It was my bad. Molly replied the next day but for some reason her reply went to my spam box, which is bizarre. I would not expect the response from the recipient to go to the spam but that's what happened and I have found out it only four days latter. Before that I have contacted Coffee Shrub, as I was truly desperate, but they also pointed me to Molly for spare parts.
Well, sorry for the false alarm.

Nunas
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#4: Post by Nunas replying to MarkG »

I'm happy to hear that Molly is still her responsive self. Once before, I remember we had a post on H-B about her being non-responsive; but I've never found that to be the case. BTW, have you determined what caused the original elements to die? You wouldn't want to go to all the trouble and expense of putting in new ones only to have them blow, too.

MarkG (original poster)
Posts: 19
Joined: 17 years ago

#5: Post by MarkG (original poster) »

Nunas wrote: BTW, have you determined what caused the original elements to die?
No I didn't. Actually it happened gradually. A year ago I noticed that my drum started to make scratching noise. When I examined the internals I noticed that the drum was warped and was scraping on heating elements. I was able to bend them a little out of the way just to stop the scratching. But I also noticed that the elements themselve were not as smooth as they used to be. I suspect that I have overheated roaster during preheating at one time. Later I've noticed that when I set heating to maximum amperage, it did not go to 10 amp as before and few weeks ago it was even worse. The day the elements failed I noticed that the amperage dropped to 5 amp in the middle of the roast. To save the roast a reduced the air to almost 0 and after few minutes the amperage dropped to 0. The roaster was dead but I was able to coast to the second crack and, ironically, with its last breath it produced the best roast I ever had on it. Even graph did not show the usual dip in temperature at first crack. It was perfect in all senses. The perfect death. Sigh...

Nunas
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#6: Post by Nunas »

MarkG wrote:No I didn't. Actually it happened gradually. A year ago I noticed that my drum started to make scratching noise. When I examined the internals I noticed that the drum was warped and was scraping on heating elements. <snip>
Thanks for the info. I'll include a warning about overheating in the next amendment of the Quest Handbook.

MarkG (original poster)
Posts: 19
Joined: 17 years ago

#7: Post by MarkG (original poster) »

Finally decided to check the voltage in my house. It's 122.3V which tells me that I'd better keep my amperage below 9A to be under 1100W. Well as they say nothing in life comes so easy and cost us so much as experience.

Nunas
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#8: Post by Nunas replying to MarkG »

The United States and Canada use a supply voltage of 120 volts ± 6%. So, your mains voltage is well within normal. Years ago, it was nominally 110, then for a time 117. Now it's nominally 120. But, in reality, it can fluctuate significantly and still be considered normal. My mains run about the same as yours, and I whack my heaters full on much of the time. I don't think the voltage was the problem, unless, of course, you had a sustained period of overvoltage a while back (unlikely). Also, when you run your Quest, the voltage will sag from the no-load voltage you probably measured.

The most likely explanation is overheating, probably during warm-up. On my M6, I spliced a solid state relay into the heater line and hooked it up to a PID. The PID reads the temperature from a probe between the drum and the case (IE MET). I set the PID such that MET can't go beyond 350 C. I've had it set as high as 450, just to see what happens (nothing bad). But, for the batch sizes I run, a warm up to 350 C until the roaster is stable is enough. Somewhere, here on H-B, I posted how to do this. It would apply equally well to an M3.

Edit: Simple PID for Quest Roasters