yellow natural gas flame on my Brutus 10

[billtzk]

I have my Brutus 10 operational in manual bare-bones mode. That is, my burners are assembled and working with manual values. I don't have my pumps and chiller and automatic gas valves and temperature control electronics installed or working yet.

I tested my burners today and they work, but poorly. It took 3.5 hours to boil 13 gallons of water in a keggle. The flame from my 8 inch 20 jet burners seems weak and lackadaisical, flickering about and licking lazily around the 2 inch square steel tubing of the stand frame, and occasionally up the sides of the keg. It's not a concentrated, focused, hot flame like an LP jet burner puts out.

Pressure too low? Not enough oxygen being supplied to the burners? Any ideas on what could be wrong and how to fix it?

I will post some pictures of my stand and burners on photobucket tomorrow.

 

[EvilTOJ]

Sounds like the pressure is too low, or the mix is running too lean. You should be getting a strong, blue flame with it yellow only at the very tips of the flame.

 

[billtzk]

My gas pressure should be set to 7 inches of water column. It smells like it is burning rich, like there's too much fuel for the amount of oxygen. These ring burners don't have a separate venturi like an LP jet burner has, so I'm wondering if it's getting enough oxygen. I have no idea how I'd supply more, if that is what the problem is.

Here are some pictures Natural Gas Brutus 10

 

[Bobby_M]

Let's talk about your gas supply. Starting with the origin from your meter/regulator trace how many feet of x diameter pipe you have before it branches off to the next lower diameter. How many feet of that x diameter do you have before you get to your stand, etc..... It's very possible that you don't have the flow you need to supply that many jets. Been there done that.

 

[sigmund]

I thought a yellow flame was a sign of a rich mixture? Or, are you saying that there isn't enough gas flow to pull in the right amount of air?

 

[Bobby_M]

Right... burners use a venturi effect (no matter where the intake is) to draw in air. If the flow is too low, it doesn't pull enough air in. You essentially flood the area above all the buners with gas and not enough o2 to burn it.

 

[BrewSapiens]

I believe that people had to lower thier burners to 4"-5" below the kettle to get adequate air for the burners to function. Check with some of the other Brutus builders for their input.

 

[Bobby_M]

Well that too, but an inadequate flow is another reason. You can plumb in an inline manometer to check your pressure drop while you're running the burner. If the pressure goes from like 7 w.c. to 2-3, you know you don't have the pipe sized correctly out to your stand. I need to get around to it myself.

 

[billtzk]

Bobby M, my gas line is in the backyard near my meter. The pipe that supplies my stand is the same size as the pipe that exits my meter from the gas company. It's about 1.25 or a tad larger in outside diameter. 1 inch pipe, maybe?

It is connected to the pipe exiting my side of the gas meter roughly two feet underground, directly below the gas meter. It runs 5 feet horizontal, then goes up about 3.5 feet to a lock box where I have a large valve that necks it down to a 3 foot long 1/2 inch yellow flex line (5/8th inch OD). It connects to the 4 foot long 2x2 inch gas manifold built into my stand, which you can see in the picture.

So total length from the gas meter is 2 + 5 + 3.5 = 8.5 feet of 1 inch steel pipe, then on the other side of my shutoff value, it is 3 feet of 1/2 inch yellow flex line that connects to my manifold.

Edit: The stand is the closest appliance to my meter. With one brew stand burner going full blast, my gas range in the house, which is dozens of feet further down the line, shows no perceptible difference in how it burns. It seems to get a full flow of gas.

 

[Bobby_M]

Ok, for sure it's not a supply issue.

Did you do a flame test without the kettle in place? As others have noted, the distance between the burner and kettle matters but if you're not getting a clean flame with no kettle, then there's a problem with something else other than the spacing.

 

[billtzk]

I just tested without the kettle. It's kind of hard to see the flame in the daytime, but at full open valve it seems like a big wild and woolly flame with a fair amount of yellow that whips around in an uncontrolled fashion. Definitely not a clean tight burn. At partial valve it seems about the same, but less intense and still unfocused.

The tips of the burners are 1.75 to 2.25 inches from the bottom of the keggle, so I guess that is too close and I'll need to lower the burner. But since I'm not getting a clean burn on a bare burner, there must be something else wrong.

 

[Bobby_M]

A few other ideas... Are you geting any gas leaking out of the threads on the BOTTOM of the burner tips? If you are, you should see yellow flames billowing out of there. Is there a chance your orifices are LP sized? I don't have any round feeler gauges so it would be hard for me to tell you the size of mine <hold the dick jokes please>

 

[billtzk]

No leaks around the bottom of the jets that I can see. They appear to be well-sealed with some kind of sealer. I don't have round feeler gauges either, but I specifically ordered Natural Gas burners, not LP, and they were marked as such on the box.

I haven't been able to google up solid info on the orifice size for NG. Apparently it is not a fixed size, but depends on a variety of factors including supply line length and diameter, gas pressure, and BTU/hr for the appliance. So for the moment I have to take it on faith that these are really NG burners.

 

[billtzk]

Fixed. I lowered the burners 2.5 inches, and now I can bring about 12 gallons 85 degree water to a rolling boil in 37 minutes at full open valve. A little faster would be nice, but I can handle 37 minutes. That burner is a monster at full throttle. You can't stand right up next to it very comfortably. It puts out some heat to the surroundings.

After coming to a boil, I found I could throttle back to half open valve to keep a good constant gentle rolling wort boil going.

Thank you all for the help.

 

[kladue]

Try raising the keggle above the frame 1"-2" so flame flow up and around keg instead of having to go around frame. bolt 3-4 pieces of 6" long angle iron to the top side of the frame to support keggle above frame and let flame flow up around keg.

 

[billtzk]

kladue you saying I should raise the kegs up above the frame another inch or two in addition to the 2.5 inches that I already dropped the burner? I could easily drop the burners another two inches, but it seems like you are implying that the frame (and maybe the shrouded bottom of the keg?) is a problem for gas flow. Or am I misunderstanding you?

I'm thinking that raising the kegs up above the frame might decrease stability by raising the center of gravity. Bobby M, I think it was, said in another thread somewhere that his stand nearly tipped over a couple of times. That's a lot of fluid and grain weight up there. Also, I can comfortably look into my kegs right now, but I couldn't if I raised them further. I can't chop the legs two inches to compensate without cutting off my storage shelf on the bottom.

 

[kladue]

An alternative would be to use a 1" hole saw and put holes in the keggle skirt to vent the combustion gasses instead of having them having to flow under and around frame.

 

[Bobby_M]

I might do that on my BK to try it out but I'd go with smaller holes like 3/8 or 1/2" at most. Thing is though, my burners run a LOT better now that I plugged up a few burner tips.

(I've never had any tipping problems btw, must have been someone else).

 

[billtzk]

Drilling the skirt sounds like the way to go. I'm going to try it with 5/8ths inch holes since I have a titanium drill bit in that size. I might try plugging some burner tips to try to get a cleaner burn, but it looks 1000% better now just from dropping the burners. How did you plug your tips?

Sorry Bobby, the tipping comment was from korndog in the very long Brutus 10 thread. My stand is so incredibly stable that I can't imagine that being a problem so long as the overall height and the center of gravity remain reasonable, but I haven't had it fully loaded with all kegs filled.

 

[korndog]

Drilling the skirt sounds like the way to go. I'm going to try it with 5/8ths inch holes since I have a titanium drill bit in that size. I might try plugging some burner tips to try to get a cleaner burn, but it looks 1000% better now just from dropping the burners. How did you plug your tips?

Sorry Bobby, the tipping comment was from korndog in the very long Brutus 10 thread. My stand is so incredibly stable that I can't imagine that being a problem so long as the overall height and the center of gravity remain reasonable, but I haven't had it fully loaded with all kegs filled.

Try locking one of your front casters and moving the unit. It will easily tip over. I have small kids and am always thinking about this kind of stuff, so maybe I'm over cautious. I strapped mine down just to be safe.

I don't have keggles, so I can't really comment except to say that 4" from bottom seems like a good distance for burners on my system.

 

[Bobby_M]

I plugged some of the burners with M8-1mm bolts: https://www.homebrewtalk.com/showthread.php?t=52154&highlight=taming+wild+beast

Hmm, it looks like the brutus clones have a high center of gravity when they could have been 10" shorter.

 

[billtzk]

I thought about making mine shorter, but I wanted a shelf on the bottom, so I kept the original height. I'm using 4 inch castors. I may swap them out for 2 or 3 inch and use the 4 inch castors on my welding table that will be my next project.

 

[EdWort]

Try locking one of your front casters and moving the unit. It will easily tip over. I have small kids and am always thinking about this kind of stuff, so maybe I'm over cautious. I strapped mine down just to be safe.

I don't have keggles, so I can't really comment except to say that 4" from bottom seems like a good distance for burners on my system.

Nice bling! Are those 20 gallon or 15?

 

[korndog]

Nice bling! Are those 20 gallon or 15?

Those are 15 Ed.

Thanks!

 

[nicksteck]

do you have a regulator on the gas, you meter is sending the gas out at 6'' - 7'', you need to bump it down to 3.5''

 

[billtzk]

nicksteck, I don't think the appliances in my house would run correctly on 3.5 inch WC. My pressure is currently set to 4 oz of pressure. Some time back in post 17 of the ASCO Red Hat Valves thread I worked out that was roughly 7 inches of WC, and I think that is typical for residential gas delivery. So you are right about my current pressure. But it's hard to see how my jet burners would benefit from a lower pressure than even my gas stove inside my house could run on. The stove in my house is rated for a maximum of 14 inch WC. I was actually thinking of increasing the gas pressure to get a hotter flame on my stove.

 

[Bobby_M]

Is there a secret screw on the meter/regulator that will adjust the pressure?

 

[nicksteck]

all appliances have a biult-in regulater, you deliver 6''-7'' of pressure and then the appliance regulates it down to 3.5'', gas is measured in inches of water column, there is 28'' of water column in a pound. the reason you are running rich is because your sending more gas than what the burner is designed to take. the jet burners have the air shudder built into every burner tip, you cannot send more o2 and more gas than what it is designed for.

trust me, i own an heating repair company and our company has 35 years experiance repairing appliances

 

[kladue]

Get the gas company to turn it up, insurance comapnies take a dim view of mishaps related to homeowner adjusted regulators. With the competively built appliances designed for 4"Wc gas pressure it is not wise to turn the pressure up much higher. Get a high pressure meter set (2 Psi) for an emergency generator, and a secondary regulator for the brew rig which you can play with without endangering the household appliances.

 

[billtzk]

all appliances have a biult-in regulater, you deliver 6''-7'' of pressure and then the appliance regulates it down to 3.5'', gas is measured in inches of water column, there is 28'' of water column in a pound. the reason you are running rich is because your sending more gas than what the burner is designed to take. the jet burners have the air shudder built into every burner tip, you cannot send more o2 and more gas than what it is designed for.

trust me, i own an heating repair company and our company has 35 years experiance repairing appliances

Alright, I'm sold. The recommendation of someone who is in the business can't be beat. I hope you can give me a regulator recommendation too.

As I described in post 9 of this thread, I have a run of 8.5 feet of 1 inch pipe T'd off my gas meter to a shutoff valve inside of a locked box attached to a column on my back porch. It necks down to a 1/2 inch (5/8ths OD) yellow flexible appliance line that connects to my brew stand manifold.

I believe there are regulators that I could put on the hard pipe supply line, and there are also appliance regulators. If possible, I'd prefer put a regulator designed for an appliance on the brew stand at the 1/2 inch manifold input coupling. That would position it after my back porch lock box cutoff, and avoid the trouble of shutting off the gas at the meter again. Is there a regulator of that type you could recommend? Maybe something like a gas stove regulator?