Hottop Drum Seize/Jam

[CyclingCraig]

Hi all

I was doing my 4th roast in my Hottop 8828B last night.

About 8 minutes into the roast, I started to hear a loud metal on metal scrapping and within 10 seconds the drum locked up and stopped turning

I quickly tried loosing the gold knob a little, maybe a tap or two to see if that would get it going, but nothing... I panicked and pressed the eject button and let the machine go thru most of it's cooling cycle, but the drum NOT turning?

I waited for it to cool, removed the drum and checked for jammed beans and stuff, didn't really find much, but I did see where it was rubbing. It was rubbing on the "Bearing Plate"? I put everything back together, made sure the drum was set in all the way and then just "snugged" the 4 screws holding the bearing plate to the unit, and tried again?

All seemed ok this time? Got a nice roast out of her

1) do you think I hurt the motor from the time the drum was jammed?
2) Now I am paranoid that something is wrong with my "baby", Should I just not worry and forget about it and call it a fluke?
3) Do others ever have Drum Seizing problems?

I am going to try another roast tomorrow and see how that goes?

[Randy G.]

Hi all

...........About 8 minutes into the roast, I started to hear a loud metal on metal scrapping and within 10 seconds the drum locked up and stopped turning ..............

1) do you think I hurt the motor from the time the drum was jammed?

No. The motor and gear case, especially in later models, is quite robust.

2) Now I am paranoid that something is wrong with my "baby", Should I just not worry and forget about it and call it a fluke?

My guess is that there was a little rock in there that jammed the drum.

3) Do others ever have Drum Seizing problems?

My did twice- once from a rock and once from a thermocouple probe inserted too far into the bean leading chute. Those are difficult to remove when bent into a boomerang shape.

Burnish the scrape to smooth it out a bit and check the machine without beans to be sure it is turning smoothly when fully warmed up. Also be sure that the drum mounts fully into the motor shaft, and all should be OK.

[CyclingCraig]

Thanks Randy

I am just so paranoid about hurting my new machine.. I LOVE roasting my own coffee. I will do a test run tonight with no beans to get the unit up to temps.

Any suggestions if it is still rubbing the (Bearing-less bearing plate? Is there any adjustment there?

Actaully just placed my first order with SweetMarias.. 2#'s Monkey, 2#'s Liquid Amber and 2# of a Kenya Nyeri for french press at work

Thanks again

[Randy G.]

Here are a few tips off the top of my head- some apply more to the older machines, but it will supply some piece of mind:\

- With the roaster UNPLUGGED, remove the front cover and the bean loading chute cover. Place a finger through the bean chute so you can feel the interface of the drum and the back wall. Slowly rotate the drum by hand from the front of the machine and feel if the drum is running true. The drums of the newer machines have a support arm welded back there 9the old ones did not), but it is still worth checking.

- As you are doing that test, watch the front of the drum to see if it is fairly perpendicular to its shaft and square to the front of the machine.

CAUTION: with both of the above tests, be careful with fingers (and toes, as the case may be) when turning the drum!

- There are times when the front bearing does not push hard enough to keep the drum away from the front of the machine., This can be adjusted by removing the bearing plate, removing the drum, and replacing he bearing plate with the drum out of the machine. You can now bend the bearing plate's arm a bit towards the back of the machine. Don't go crazy- a couple of millimeters when the bearing plate is at rest is sufficient.

- Look into the motor's slotted shaft at the back of the roasting chamber to be sure that there am no foreign materials in there which might prevent the drum from fully seating into the motor.

- Check the end of the drum's shaft where it seats in the front bearing and the dimple in the bearing itself to be sure these are clean and smooth.

- Be sure that the bearing plate mounts flat against the front of the machine when the screws are tightened (DO NOT OVERTIGHTEN THE SCREWS).

These roasters seem to be very tough from my experience. If there is a problem, Michael at Hottop is quite accommodating and helpful if there is repair needed. Parts are easy to replace, and most are relatively affordable. Check the repair procedures at the Hottop USA website if there are any questions.

[Niko]

If there is a problem, Michael at Hottop is quite accommodating and helpful if there is repair needed.

I agree!
My brand new 8828P arrived with a bad safety switch. The unit wouldn't even roast out of the box so imagine the horror of a bad out of the box experience. Michael took care of the problem ASAP and sent another unit.

[Randy G.]

I agree!
My brand new 8828P arrived with a bad safety switch. The unit wouldn't even roast out of the box so imagine the horror of a bad out of the box experience. Michael took care of the problem ASAP and sent another unit.

As a point of note, if the part in question is the one that is activated by the chaff tray, there are times when the chaff tray does not press against the arm of the microswitch. One solution is to bend the tray to make it just a little it wider. I have had that happen a couple of times.

[mrgnomer]

I got my Hottop programmable with the drum shaft knocked out of the hole on the front glass cover and the front glass cover so out of line the brass screw wasn't going in straight. Thanks UPS

Anyway, I didn't know anything was wrong (first Hottop for me) until I started roasting and the drum wouldn't turn. After warm up I knew something was wrong. The drum motor was stalled all through the warm up stage.

I shut her down, lined everything back up, and no problem. Motor seems no worse for wear. Over 60 roasts later she's still going fine. Yes, the Hottop's can take some abuse.

[CyclingCraig]

THanks guys for the support

I ran a batch last night and all seemed fine, I just have to be careful to put that glass cover (Not the bearing plate) on properly, I "THINK" it might have been misaligned last time and gold knob too tight?

Last night it "seemed" ok.. may do another roast tonight or over the weekend.

[mrgnomer]

THanks guys for the support

I ran a batch last night and all seemed fine, I just have to be careful to put that glass cover (Not the bearing plate) on properly, I "THINK" it might have been misaligned last time and gold knob too tight?

Last night it "seemed" ok.. may do another roast tonight or over the weekend.

Too tight would be a temptation, I think. Screw it in until it seats but don't tighten too much, I'd say, or you might put more pressure on the shaft than you need to and the drum may not spin as freely. Misaligning and cross theading the screw would be difficult unless the plate or shaft weren't on straight for some reason.

[Randy G.]

Too tight would be a temptation, I think. Screw it in until it seats but don't tighten too much, I'd say, or you might put more pressure on the shaft than you need to and the drum may not spin as freely. Misaligning and cross threading the screw would be difficult unless the plate or shaft weren't on straight for some reason.

The LOOSER the gold screw is, the MORE pressure the bearing plate puts on the drum's shaft. Tightening the gold screw PULLS on the bearing plate, allowing the drum to more further forward-- towards the glass window, thus allowing it to rub on the front of the machine and make noise.

[mrgnomer]

The LOOSER the gold screw is, the MORE pressure the bearing plate puts on the drum's shaft. Tightening the gold screw PULLS on the bearing plate, allowing the drum to more further forward-- towards the glass window, thus allowing it to rub on the front of the machine and make noise.

Thanks for the clarification.

[Cosmo]

Craig, as another 8828B owner, with one roast under my belt, I can't say how glad I am that there seems to be no problem with the roaster. When I saw your thread title, I had a bad feeling for a moment there.
Mike

[Randy G.]

Craig, as another 8828B owner, with one roast under my belt, I can't say how glad I am that there seems to be no problem with the roaster. When I saw your thread title, I had a bad feeling for a moment there.
Mike

Don't be (too) paranoid, folks. Michael at Hottop USA is great to deal with whether it is a warranty problem or not. he is an engineer and can usually diagnose any problem through E-Mail or over the phone. Parts are readily available, and the entire repair procedure covering virtually every part of the roaster is available on the Hottop USA website. You can become more familiar with the machine by looking through the procedures. A couple of screwdrivers and a needle nose pliers can disassemble nearly the entire roaster.

[CyclingCraig]

Craig, as another 8828B owner, with one roast under my belt, I can't say how glad I am that there seems to be no problem with the roaster. When I saw your thread title, I had a bad feeling for a moment there.
Mike

Cosmo,
Yeah DON'T worry, mine is acting JUST perfect now, I think it might have been operator error

Anyway, I have a question for you? what was the total roast times for you? Mine seem REAL short compared to others?
Check out my other post on this thread: (3rd one from the top.)
http://www.home-barista.com/forum...ised-t4291-20.html

On your first roast, did you heater power change by itself at all, or did it stay at 100% the whole time?

[Cosmo]

Craig, on my first roast in the hottop, I used a mixture of Mexican Oaxaca (75%) and Nicaraguan from Sweet Marias. I just used the auto program and loaded 225 grams of coffee when the beeper started at 166 degrees. From there itwas about 7 minutes to first crack, which started when my machine said the temp was 390 degress. about a minute later, I heard what I thought were the first snaps of second crack, and I dumped the beans. I'm not 100 % sure, but I think the power cycled through the roast. I need to figure out how to strecth the time from first to second, but this was the first roast and I was happy. Will roast some more this weekend and may hve more info then.
Mike

[CyclingCraig]

Hey Cosmo

Thanks for the updates.. I am going to roast some more over the weekend as well.

My current profile has me turning the heater to 50% at the 6 minute mark(Counting up from the time the beans are put in)
Keep it there for 2 1/2 minutes, then back up to 100% until 1st crack, which begins at about 11 minutes into the roast(Again counting up). As soon as first crack starts I turn header to 40% and leave it there for the rest of the roast. First crack last about 60 to 90 seconds. there is about a 45s to 60s pause between end of 1st and start of 2nd. I eject a couple of snaps into second crack. ? Seems to work for me

Keep me updated as to your progress and what you find

[Cosmo]

Craig, I just roasted another batch. Sumatran Lintong, 250 grams. The coffee looked a little funky, pre roast. Lots of broken beans, and some discoloration on some of the beans. I picked out the worst offenders, then started on auto, but this time I messed with the parameters a bit. I pushed the time up to the max, and about 4 minutes into the roast I turned the fan on to 50%. Then I cut the heat down to around 40%, and then off completely for a minute or two. The weird thing was although I was able to stretch the time to first crack to 9 minutes, the temp readout at the begining of first was only 377. About a minute into first I cranked up the fan to max, and shut off the heat. I still started second crack about a minute later, let it go for about 30 seconds and dropped the beans into the cooling tray. I don't know how this one turned out. I'm gonna let it rest for a couple of days before I try the coffee.
Mike