Diedrich IR2.5 LP gas pressure?

[CG901]

I have been struggling to achieve the roast qualities previously accomplished on my sample roaster with this new Diedrich. I am using LP gas. a large cylinder, and correct regulator, but only getting at best 9.5" WC of pressure. Diedrich's literature says it should be 11", but they told me all is well at 9-10". I am having difficulting turning a medium (3 lbs) roast after first crack over 400F. I am dropping between 13-14 minutes. I know that Infrared burners don't respond as quickly to flame adjustment. I am wondering if the backpressure of my exhaust system is less than optimal. Any suggestions from those who have been there? Thanks

 

[peterjschmidt]

I use an Ambex 2K with LP, so it's not exactly apples to apples, but I get just over 9 on my gas gauge at full throttle, and it's fine.

Are you saying you can't get the roast to climb past 1C, and that 400* is the highest your roast will go? That sounds odd.

 

[CG901]

Peter, thanks for the comment. I typically charge at 440-450 ET and 400 BT which gets a TP around 200, and from there can stay with nicely declining BT ROR most of my profiles until after 1C where I seem to stall every batch. I would like to see the BT rise to approach 420-440. Discounting the differences in TCs, on my sample roaster I was able to cut burners early in 1C and watch the BT continue to rise until drop. Now albeit with a 50% of capacity charge and a much larger machine, it's not happening.
As I mentioned, I am considering air flow to possibly be a factor here. I am running my vent horizontally through the wall for a travel of about 4 ft, then exhausting. I am wondering if this is allowing for more airflow than the machine was designed.
Typically, an elbow, then vertical run of 6-10 ft. of exhaust vent pipe would slow the extraction of exhaust. I have basically no back pressure.

 

[peterjschmidt]

You say you're running batches at 50% of the roaster's capacity? The first thing I thought of until reading that is you have the thing way maxed out, but I guess not.

Is your declining BR ROR too much a decline? What would happen if you didn't slow down quite as much going int 1C? Remember that up to 1C the beans are endothermic, and during 1C they are exothermic, but then after 1C the go endothermic again. It could just be that you've the gas dialed back so far during 1C that you don't realize all of the ROR is due to the beans giving off energy (which isn't good for favorable flavor compounds forming, and the reason we don't like stalls in 1C).

Depending on the desired roast level and type of bean, a general profile for me is; drop at 415, WP9; TP at 170, WP9; 280*/5min WP9; 330* WP7; 350* WP5; 370* WP3; 390* WP5. In that scenario, WP is water pressure, and assume 1C is 375*, and I'm dumping at 410, and 2C would be 420* if I let it go.

 

[CG901]

Peter, thanks for your general profile. I have tried adjusting WP during 1C to maintain BT ROR. I may just be over-developing while trying to achieve a darker appearance and higher drop temps. I am at a loss to explain why I don't have better control, although I have read the IR burners are far less sensitive to changes in WP. I am thinking of adding a cyclone fan rheostat so I can dial back the airflow early in the pre-1C ramp up.
Also will try an earlier drop as I am approaching 14 minutes and that is simply too long a development phase.

 

[Hankua]

I'm not understanding why your only getting 9.5" WC on a propane cylinder. With my 20lb tank and a high pressure regulator I can get 4kPa on my gauge which converts to 16" WC. Although my regulator was imported, they are available from Marshall Excelsior. Welcome to Marshall Excelsior Company

Looks like your LP setup came from a local gas company, I'd call them out and switch out some parts to supply more pressure.

One last question, as the machine can be supplied with NG or LPG jets, the correct version is installed?

 

[CG901]

Hankua, thanks for your comments. I did install the LPG jets from Diedrich and had the regulator adjusted to full pressure, which as, as I recall 13" WC, which should give me more than 9.5".
It is possible the Diedrich gauge is faulty, but when I questioned them, they simply said anything over 9" s/b fine......

 

[Hankua]

I see the idea of air flow being a possible issue. What about removing the exterior cap and putting a 4"-3" transition from HD? Or something else to restrict air for a test?

 

[CG901]

I was interested in whether Peterschmidt's general profile was even close to what I was doing. I can tell you that my machine needs a lot more WP to maintain BT that yours. If I scaled back to WP3 (390F) and during 1C, my BT would drop. I can only guess that your machine is either more efficient, meaning you are getting more BTU from your WP measure than I. It could also be the IR feature of my machine. I've tried a few more roasts today. Getting better but far from my goal.

 

[gearhound]

I have been struggling to achieve the roast qualities previously accomplished on my sample roaster with this new Diedrich. I am using LP gas. a large cylinder, and correct regulator, but only getting at best 9.5" WC of pressure. Diedrich's literature says it should be 11", but they told me all is well at 9-10". I am having difficulting turning a medium (3 lbs) roast after first crack over 400F. I am dropping between 13-14 minutes. I know that Infrared burners don't respond as quickly to flame adjustment. I am wondering if the backpressure of my exhaust system is less than optimal. Any suggestions from those who have been there? Thanks

I got an IR2.5 two months ago and have been experiencing the same exact issues. I spoke with Diedrich tech for weeks and didn't get anything solved...they said I could run it at 13 WC though. I started off with a cheap BBQ regulator and was getting 10-11WC and am now running a cheap "Charbroil" dual-stage BBQ regulator that gets between 9-11WC depending on how I adjust the gas between roasts. I definitely need a better regulator as I'm not getting consistent gas pressure! I'm planning on ordering the Marshall one from Mill City and trying it out at 13WC, but wondering why I couldn't go a bit higher with it? I've played around a lot with the high-low flame Allen-key adjustments on the Dungs gas valve and now feel I simply need more gas going in.

I'm also concerned that the Cyclone is way too powerful as I'm currently just rolling my roaster out onto my driveway and blowing the chaff directly out without venting. Did you ever find a way to limit it's power? Without any restriction I know I'm blowing way too much air out of the drum.

I've been getting really frustrated these past 2 months with it and have actually been thinking about selling it if I can't get it to efficiently roast 4.5lb batches. Here's my last 4.5lb batch #'s: at a 440 charge temp I drop with the gas at 3WC and crank it to full power (10-11WC) a minute in and have to go full power until 1st crack and then back off to 7wc to finish the roast. To hit 1st crack at around 11minutes I have to keep the airflow thru the cooling bin all the way until 380 and then go 50/50 for a minute and then thru the drum for the last 30-60 seconds of the roast.

Have you found any good solutions to get up near a 4.5lb-5lb batch size?

What regulator are you using and how big of a propane tank? I'm currently using a 20lb. BBQ tank.


Thanks for any suggestions.

 

[CG901]

Gearhound - Firstly, I am using the regulator that US Roasters recommended (Fisher R632) which is supposed to put out 11-13" WC. (32.4 mbar) I have it adjusted to the max output. Not sure why I can only max out at 9-9.5" WC on this roaster, but I suspenct it may be the manometer reading wrong. I finally had my DUNGS gas valve completely stop working, so ordered a new one from Diedrich. After replacing the old one, I got off three roasts today. The gas adjustment felt more responsive, and I was able to get my ET to 450F easily, with BT 190-425F during the roast. I still believe I am getting too much airflow, and am planning to install a variac to control the fan speed. On batch size, I am still working with 2-3 lbs until I can resolve my control issues. No need wasting more good beans.
I bought a 40 lb propance tank to be certain I had plently of pressure and wouldn'd have to refill as often.

 

[gearhound]

Gearhound - Firstly, I am using the regulator that US Roasters recommended (Fisher R632) which is supposed to put out 11-13" WC. (32.4 mbar) I have it adjusted to the max output. Not sure why I can only max out at 9-9.5" WC on this roaster, but I suspenct it may be the manometer reading wrong. I finally had my DUNGS gas valve completely stop working, so ordered a new one from Diedrich. After replacing the old one, I got off three roasts today. The gas adjustment felt more responsive, and I was able to get my ET to 450F easily, with BT 190-425F during the roast. I still believe I am getting too much airflow, and am planning to install a variac to control the fan speed. On batch size, I am still working with 2-3 lbs until I can resolve my control issues. No need wasting more good beans.
I bought a 40 lb propance tank to be certain I had plently of pressure and wouldn'd have to refill as often.

Have you adjusted the High & Low flames on the Dungs Valve with an Allen Key? What happened when it broke? Zero gas flow?

I just got the Marshall high-output regulator (12-24WC), but unfortunately the Dungs valve I believe has its own regulator built into it and I'm still only able to get 11WC. I've only done 1 roast so far, but it doesn't seem to "ice" like the cheaper Charbroil regulator did...I can go down to 3 WC and back up to 11WC without it getting stuck at 9WC.

According to Diedrich tech support I should be able to run it at 13WC, but I honestly don't think they really know anything about running on a propane tank.

I think not having venting set up right now is definitely resulting it way too much airflow....is this the Variac you are looking into getting? amazon.com/Variac-Variable-Transformer-300va-Output/dp/B006NGI8VS

Are you running Artisan? What sort of Rate of Rise are you getting in the drying phase?

I'd love to stay in contact and try to sort this out together if you're game? Feel free to shoot me a PM with your email.


Take Care,
Matt

 

[Amhas]

Gearhound - Firstly, I am using the regulator that US Roasters recommended (Fisher R632) which is supposed to put out 11-13" WC. (32.4 mbar) I have it adjusted to the max output. Not sure why I can only max out at 9-9.5" WC on this roaster, but I suspenct it may be the manometer reading wrong. I finally had my DUNGS gas valve completely stop working, so ordered a new one from Diedrich. After replacing the old one, I got off three roasts today. The gas adjustment felt more responsive, and I was able to get my ET to 450F easily, with BT 190-425F during the roast. I still believe I am getting too much airflow, and am planning to install a variac to control the fan speed. On batch size, I am still working with 2-3 lbs until I can resolve my control issues. No need wasting more good beans.
I bought a 40 lb propance tank to be certain I had plently of pressure and wouldn'd have to refill as often.

Hi CG901,

I have an IR1 and I'm running off NG, but when I run my roaster at 50% capacity it doesn't respond like it would at 80 or 90% capacity. Air flow I would use would likely be no more than 50/50 when at only 50% or less capacity. Where as when running at or near capacity I will go to full (roasting drum) open at around 310 - 315 deg F which is usually around 5 minutes 10 seconds to 5 minutes 30 seconds into the roast. That generally gets me to 1C between 8m 30sec and 9m 10sec (depending on the bean and what I'm shooting for), and I drop between 2m 30sec and 2m 45sec which is around 414 deg F (plus or minus a couple degrees). Different machine but just a thought. That all said I very rarely run at 50% as I find it hard to control. When I order samples I order 800 - 900 grams to get a more consistent roast.
I will note that the IR burner doesn't respond immediately, but delayed by 30 seconds or so. I will tell you that I drop at around 380 deg F, with the gas on low (turned all the way down) and then crank it up incrementally after TP (around 1:15 between 175 and 180 deg F) am generally at or very near full throttle by 3 minutes into the roast in order to maintain steady slow ROR and reach 1C around 9 minutes. I don't mention WC here because obviously I'm using NG and you're using LP and I don't know how that will relate. I do have a gauge on my NG line and I'm running around 9 WC.
Love to hear more about the variac as I do find that setting the damper at full in the winter (cooler temps) a bit to much. I have found that I can vary that damper by setting it in between 50/50 and full seems to work reduce the air flow. I do think I'm getting much more consistent results once I managed the air flow better but as outside temps have risen I am finding it much easier to maintain the ROR as well. Beans are different and some like to stall or bounce up (ROR) at 1C, followed by what can be a sudden drop in temp. Each bean and the age of the bean can affect this is what I have found and it has been the largest challenge I have had in controlling my roasts.
Good luck and I look forward to hearing more about what you learn.

 

[gearhound]

Hi CG901,

I have an IR1 and I'm running off NG, but when I run my roaster at 50% capacity it doesn't respond like it would at 80 or 90% capacity. Air flow I would use would likely be no more than 50/50 when at only 50% or less capacity. Where as when running at or near capacity I will go to full (roasting drum) open at around 310 - 315 deg F which is usually around 5 minutes 10 seconds to 5 minutes 30 seconds into the roast. That generally gets me to 1C between 8m 30sec and 9m 10sec (depending on the bean and what I'm shooting for), and I drop between 2m 30sec and 2m 45sec which is around 414 deg F (plus or minus a couple degrees). Different machine but just a thought. That all said I very rarely run at 50% as I find it hard to control. When I order samples I order 800 - 900 grams to get a more consistent roast.
I will note that the IR burner doesn't respond immediately, but delayed by 30 seconds or so. I will tell you that I drop at around 380 deg F, with the gas on low (turned all the way down) and then crank it up incrementally after TP (around 1:15 between 175 and 180 deg F) am generally at or very near full throttle by 3 minutes into the roast in order to maintain steady slow ROR and reach 1C around 9 minutes. I don't mention WC here because obviously I'm using NG and you're using LP and I don't know how that will relate. I do have a gauge on my NG line and I'm running around 9 WC.
Love to hear more about the variac as I do find that setting the damper at full in the winter (cooler temps) a bit to much. I have found that I can vary that damper by setting it in between 50/50 and full seems to work reduce the air flow. I do think I'm getting much more consistent results once I managed the air flow better but as outside temps have risen I am finding it much easier to maintain the ROR as well. Beans are different and some like to stall or bounce up (ROR) at 1C, followed by what can be a sudden drop in temp. Each bean and the age of the bean can affect this is what I have found and it has been the largest challenge I have had in controlling my roasts.
Good luck and I look forward to hearing more about what you learn.

Do you have a profile you could post? How is your roaster vented?

Even running at 11WC the whole time there's no way I could mimic your numbers on a 4.5lb roast dropping at 380 and going thru the drum at 310-315....I don't think the roast would ever finish! Finding it kind of strange that your IR-1 seems to have more power at an 80% capacity than my IR-2.5....I also roast on an old IR-7 at 80% capacity but with NG and it has a ton more power than my 2.5 does. I figured it was the bigger thermal mass of the roaster that resulted in the power difference...but with your IR1 having more power I'm wondering if its more it having bigger IR-burners? Maybe the IR-1 & 2.5 both use the same size burners?

 

[Amhas]

Do you have a profile you could post? How is your roaster vented?

Even running at 11WC the whole time there's no way I could mimic your numbers on a 4.5lb roast dropping at 380 and going thru the drum at 310-315....I don't think the roast would ever finish! Finding it kind of strange that your IR-1 seems to have more power at an 80% capacity than my IR-2.5....I also roast on an old IR-7 at 80% capacity but with NG and it has a ton more power than my 2.5 does. I figured it was the bigger thermal mass of the roaster that resulted in the power difference...but with your IR1 having more power I'm wondering if its more it having bigger IR-burners? Maybe the IR-1 & 2.5 both use the same size burners?

Hi Gearhound,

I'm more than happy to share with you. See below one example. How old is your IR 2.5? I did hear that at one point that they were a bit under powered, but the newer models have more power. That's just rumor, not sure if that's true.
Edit: Oh sorry my roaster is vented straight out the back 24" long pipe out the back wall, with just a 45 deg elbow on the end to keep out the rain.