San Fran SF6 Owners! Advice needed.

[wmark]

Was the machine originally used with natural gas or propane ?

Propane gas valves/orifaces are smaller in diameter than natural gas as it burns hotter. If originally set up for natural gas, you may have to switch out (two) of the valves. Really easy to do but need to be done by as gas guy

 

[CoffeeTec]

I thought he had mentioned fairly confidently that it was set up for propane?

But for future exploration, the propane burner orifice is drilled to #69 and the natural gas #60.

Also there is a metered connection where the gas line connects to the base of the burner manifold.

If you are running propane that connector/ orifice is usually black (KR14), and for natural gas it is silver (A26 I believe?). Both come in the pilot assembly kit.

And I am fairly certain the universal Honeywell pilot assembly is Q348U1009. SFR just bends the bracket to make them fit.

 

[Mr.GreenBean]

I am going to cross reference these connector numbers just to be sure it was set up correctly. I'm 90% sure everything checked out for propane, but it won't hurt to double check.

It's unfortunate that the support team at SF didn't walk through this with as much detail as you both have, and is possibly the reason the guy I purchased this from did not transition to the SF25 opting for another brand. I can't hold the company accountable for things the 2 previous owners should have done with this roaster, but it is my hope that Aan Fran will step up to help me make sure their roaster lives up to its potential.

Thanks again.

 

[topher]

This was posted in 09.
http://www.coffeeforums.com/forum/coffee-roasters/7090-pot-marks-beans.html

 

[Mr.GreenBean]

This was posted in 09.
http://www.coffeeforums.com/forum/coffee-roasters/7090-pot-marks-beans.html

Hey Topher! As you can see, I am still at it since we spoke several months ago. Again, thank you for taking the time to do that.

Interesting. Slowing my roast time. Slow the roast without cooking the beans through. I will have to do some more digging on this. I am conditioned to hear 1st crack between 9-10 min. It's the same as telling an alpha runner to pace the first half of a road race. It will take fighting my instincts.

 

[CoffeeTec]

I am going to cross reference these connector numbers just to be sure it was set up correctly. I'm 90% sure everything checked out for propane, but it won't hurt to double check.

It's unfortunate that the support team at SF didn't walk through this with as much detail as you both have, and is possibly the reason the guy I purchased this from did not transition to the SF25 opting for another brand. I can't hold the company accountable for things the 2 previous owners should have done with this roaster, but it is my hope that Aan Fran will step up to help me make sure their roaster lives up to its potential.

Thanks again.

If you are the third owner and are mechanically confident, you might consider dropping the burner manifold and then cleaning all of the burners.

That usually involves disconnecting the gas line (compression nut) and igniter/sensor wire from the pilot assembly, and then removing 4 bolts that hold the burner manifold to the frame.

Be careful when loosening and tightening the burners because they are brass can can snap at the threads if you don't maintain a vertical axis (rotation) while performing the maintenance.

When you have the burners out soak them in an espresso cleaner, rinse, then blow with compressed air. This is a great time to check your orifice in the base of the burner with a #69 drill bit for propane.

When reinstalling the burners you need to use hi-temp pipe dope (yellow) made for gas. Rectorseal is a good choice and they may offer it in a small tube. You don't need much.

Also take care that when you apply the dope to the burner threads so you don't fill up the orifice. No gas through hole = No flame from burner.

Blow out the manifold with the burners removed too.

SFR would be tickled that you think they have a support "team". After the sale service seems to be waning fast.

 

[Mr.GreenBean]

If you are the third owner and are mechanically confident, you might consider dropping the burner manifold and then cleaning all of the burners.

That usually involves disconnecting the gas line (compression nut) and igniter/sensor wire from the pilot assembly, and then removing 4 bolts that hold the burner manifold to the frame.

Be careful when loosening and tightening the burners because they are brass can can snap at the threads if you don't maintain a vertical axis (rotation) while performing the maintenance.

When you have the burners out soak them in an espresso cleaner, rinse, then blow with compressed air. This is a great time to check your orifice in the base of the burner with a #69 drill bit for propane.

When reinstalling the burners you need to use hi-temp pipe dope (yellow) made for gas. Rectorseal is a good choice and they may offer it in a small tube. You don't need much.

Also take care that when you apply the dope to the burner threads so you don't fill up the orifice. No gas through hole = No flame from burner.

Blow out the manifold with the burners removed too.

SFR would be tickled that you think they have a support "team". After the sale service seems to be waning fast.

Hey Coffee Tec,

I did that. The heads were pretty clean, but I gave them a soak and used the drill bit. I should have mentioned this. My awesome gas guy even disconnected some of the gas connections on the eoaster and blew compressed air through to make sure there was no blockage. I guess giving him a pourover every time he stopped by went a long way.

It was actually San Fran who walked me through the head cleaning process on the phone. They are going to sell me the part with schematics for my welding guy.

I can't lean on SF too hard since they didn't sell me this roaster directly. I just wish they had some sample profiles I could study to zero in on my own signature. They shared one Brazilian profile with me, but that was a full 6# hit hard with heat dropping a 406f. And I still think that their 4800ft altitude does not heat as quickly as my sea level does (17.5%O2 vs my 20.9% coupled with a few more lbs of air pressure needed at their altitude to reach similar temps.)

That or I am slowly slipping into a form of roaster insanity that I was not aware existed.

 

[CoffeeTec]

Altitude can make a difference, but not all supplied gas is the same either. The BTU content of gas can be formulated differently to compensate for things like altitude.


On second thought, don't worry about gas, regions, formulation, caloric, btu, altitude, as I feel this is taking you down a path you don't need to travel.

You currently have a healthy blue flame which is great, and you're going to be installing an air-flow control damper on the x-over pipe.

That modification is going to change things for the better but learning it's position during roast will be yet another experience.

I am curious what your current routine is warming up the roaster, from the time you turn it on until you charge a hopper of greens? Gas levels and elapse time?

 

[Mr.GreenBean]

Altitude can make a difference, but not all supplied gas is the same either. The BTU content of gas can be formulated differently to compensate for things like altitude.


On second thought, don't worry about gas, regions, formulation, caloric, btu, altitude, as I feel this is taking you down a path you don't need to travel.

You currently have a healthy blue flame which is great, and you're going to be installing an air-flow control damper on the x-over pipe.

That modification is going to change things for the better but learning it's position during roast will be yet another experience.

I am curious what your current routine is warming up the roaster, from the time you turn it on until you charge a hopper of greens? Gas levels and elapse time?

I'll use my Brazil as a example(both 5 & 6# batches)...

Warm the roaster up for a good hour prior to roast. A lower flame allowing the e tire roaster to warm up. I drop at 400 as my typical start (have experimented with 410 and 390, and ROR still climbs at similar rates.)

I have toyed with charging slowly at medium gas and increasing the gas at the drop, have toyed with climbing at a rapid rate with higher gas at the drop, and with dropping at different gas levels ranging between 8WC - 11WC.

If I start out below 8WC, the ROR is too flat, when I hit hard (10-11) through drying I have a ROR that I think is either creating scorching or an endothermic increase resulting in either the oils surfacing too quickly creating the "potholes" or popping the surface causing chips that are these holes.

My continued trial and error leads me to believe that I am increasing the temperature too rapidly.

What I have not tried is charging to 400, dropping at a medium gas until the temp turn, then hitting hard through the drying phase. Only, I don't think this will change much since the turn temp is not a true gague of the actual bean temp.

Any variation from the start creates a strange roast cycle where the 1st crack is not very robust. The only way I can get that robust 1st crack in the 9:30-10:30 timeframe is when I go full gas from dropping... thus, too rapid a ROR.

I just connected Artisan this morning and have been logging minutes and notes on log sheets. Only thing I have not been logging to this point is the Env Temp.

Let me see if I can post a pic of this profile which was 9.5-10WC through drying, then about a 3 sec increase per degree after by playing with gas from 3 through 6WC to maintain ROR.

 

[Mr.GreenBean]

Nope. Pic thing won't work. Headed home to meet kids off the bus. Will try from laptop

 

[Mr.GreenBean]

Nope again... Converted the photo. Saved it at a lower res. nothing... can't post a picture for some reason from phone or laptop.

 

[CoffeeTec]

Nope again... Converted the photo. Saved it at a lower res. nothing... can't post a picture for some reason from phone or laptop.

No problem with the picture. That's awesome that you let your roaster warm up for an hour. Unless you're just curious, I wouldn't worry too much about logging and roasting issues until you get the air-flow control installed. It's going to change everything and you are going to want to log the position of the damper throughout the roast too. Does Artisan allow you to customize or add events/triggers during a roast?

This is sort of 2-fold in that it explains the use of the air-flow control during warm-up, but it also describes how to warm up the roaster... they go hand in hand.

If you were NOT warming up your roaster over time that could shed some additional light on roast anomalies. Trying to get up to roasting speed too fast is also a good way to seize the drum against the face plate. The drum sets above the burners and expands quicker than the surrounding steel of the roaster. And people do find themselves in a situation where they try to play catch up, and will throttle the gas all the way back up to 10-11" in an attempt to "recover" the roast... or.... Say they normally only roast one batch of coffee per day but have never let their roaster warm up properly. When the day comes that they have to do back to back roast they will be pulling their hair out trying to figure out why the first and second roast differ so much with the same bean.

Also, do not overload your roaster. It is designed so that "X" lbs of beans tumble nicely at "X" rpm within "X" diameter drum. Imagine you're in a big hurry to get your roasting done. And you're so eager today that you decide to squeeze 7 lbs of beans into your SF6. You charge the beans into your super heated drum and the first thing you notice is the bean action through the sight glass looks a little sluggish? What do you think could potentially be happening to the beans that are laying against the super hot drum instead of tumbling evenly? You'd be surprised how many people will try to use a 1lb roaster for production and basically choke the poor thing to death.

This is basically how you would warm up your roaster with air-flow control...

- Turn on the roaster and when the pilot ignites, throttle your gas to full until the manifold is purged and all of your burners have lit.
- Lower the gas pressure down to 1.5 to 2.0" and CLOSE your new air-flow control to approximately 80% closed (almost completely vertical).
- This begins the important warm up phase and ideally your roaster should be hovering around 390 to 400 degrees (red bean temp) over the last 10 minutes of a 30 to 40 minute total warm-up period. Does that make sense?
- To stabilize the temp during warmup make subtle changes using both the air-flow and gas controls. The warm-up period ensures that the core of the roaster is heated evenly and the roaster is retaining heat as a thermal mass.
- Don't rush. If you can still lay a hand on the outer metal skin around the drum consider letting it warm up longer. If you go over your intended charge temp, NO WORRIES, make a minor tweak and let the temperature come down gradually.

Let's roast... I am totally slammed with projects but will try and post an example of air-flow position during a roast asap.

And since you've been set up for about a month, how are you venting your SF6???

Initial straight pipe run off the roaster with minimal curves at exhaust end? Yes?

How long is the total run of the exhaust?

 

[Mr.GreenBean]

You are pretty spot on in all of your guesses. I am straight up through the roof with no angles, and the exhaust totals around 10'.

I just had a HUGE breakthrough. Roasted 2 batches in a row of 5.5# and kept that air flow forward through the cooling tray until first crack. Gas only at 9, so no tipping and that 1st crack occurred at 9:17!

I was concerned having the cooling tray forward so long, but when I dropped the first batch, I did the lighter test by the trowel hole, and there was still air pulling through. Just not to the point of sucking the flame out (was concerned no flow would create a chafe fire).

Now this is not the end solution by any means, but it tells me to have that damper installed asap.

Don't know why I waited a month to hook up Artisan. I felt it would keep me from growing to know my roaster, and in turn it kept me so busy logging data to where I ignored the roast process.

I am headed to the New York Coffee festival this Sat morning before I hit a wedding in the city that night. If you by any chance will be attending, let me know. I'd love to thank you in person!

 

[CoffeeTec]

Ah, so the air damper on the cooling tray should always be closed unless you are cooling beans. Open or closed.

The SF6 is not considered a continuous roaster so if you are cooling beans in the tray (air directed through cooling tray) then you should not be charging another batch.

Typically just moments prior to reaching your desired end of roast time or temp you would engage the cooling tray sweep, move the lever forward to redirect the air through the cooling tray, drop beans.

To expedite the time between roast some people discharge the beans from the cooling tray and cool them elsewhere by fan.

As I mentioned, when you get the air-flow control installed on the x-over pipe things are going to change dramatically.

And regardless of first crack times and such, how is your coffee in the cup?

 

[Mr.GreenBean]

My medium roasts are nice with a few origins. Have yet to roast a decent batch of Colombian. Should be an easy bea to roast but either roast them bitter or flat. Getting the part soon I hope. My part is "in the production schedule" so I sould be getting a invoice soon. Not even sure what that means.