Blichmann Natural Gas Burner issue

Converted my blichmann to NG and now I can't get a decent boil. Check out this video this is a BIAB batch that has been on full gas for over 60 min and it won't get a rolling boil. With propane it was hard to keep from boiling over now I can't get a decent one


[ame]http://youtu.be/zo7FX_XTXfg[/ame]

Nobody has any insight in this? Any way I can fix this?

I use blichmann burners with natural gas all the time and have had no problem getting a vigorous boil with > 10 gallons. It looks like perhaps you don't have enough gas flow: I get bigger jets of flame that are less impacted by airflow. Is your gas on all the way, both from your supply and the needle valve on the burner? If so, perhaps your gas supply is not big enough.

There are also different grades of natural gas. It's possible your area has a low BTU NG supply.

Gameface said:

There are also different grades of natural gas. It's possible your area has a low BTU NG supply.

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I run my grill off NG also and it seems fine..guess I will have to call the village and ask them what the output is right?

adman said:

I use blichmann burners with natural gas all the time and have had no problem getting a vigorous boil with > 10 gallons. It looks like perhaps you don't have enough gas flow: I get bigger jets of flame that are less impacted by airflow. Is your gas on all the way, both from your supply and the needle valve on the burner? If so, perhaps your gas supply is not big enough.

Click to expand...

Yes both the supply and needle valve were turned up during that video. It is running off a quick disconnect with 30 feet of stainless braided gas line..can that be the problem? I really don't have a shorter line to test

Also its 3/8" line...can that be the issue?

DogFace_Brewing said:

Also its 3/8" line...can that be the issue?

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Sorry to resurrect this. I was just looking for threads on how to adjust my flame but felt I might have some good input here.

I don't know a ton about natural gas, but I do know that things like tube diameter and length of the run have a major affect on the possible BTU's you can achieve.

The top chart in this PDF is pretty useful: http://goo.gl/7345eV

It lists the BTU in thousands of BTU/hr for certain diameter pipe (I assume OD since Natural Gas usually sizes pipes by OD). The chart makes some assumptions about the gravity of gas and stuff. So for instance 30ft of 1/2" piping could supply up to 61,000 BTU. You have a 3/8" supply hose which is tiny. I'd guess that'd give you something around 20-30,000 BTU...but I don't know how long your supply line is leading up to that.

20-30,000 seems about right. A stovetop is about 10-15,000 BTU and that barely brings 5 or 6 gallons up to a boil. You're above 7.

By comparison, my piping is 3/4" black pipe for more than half the run, then it goes down to 5/8" copper for the other half. I have a 60" - 5/8" OD supply hose going to my burner. I have a 1/2" Male-thread to 3/8" Flare valve on the end of the supply (which by the way, you really should get one if you haven't already...the needle valve doesn't actually stop the flow of gas), and I join that to the 3/8" needle valve that Blichmann supplies.

Did you change the orifice in burner? I know that with some conversions you have to change that part out. However.. I have no idea whether the orifice is larger or smaller than for LPG. But, from >> THIS << article.. looks like it's larger.. and THAT may well explain your problem..

HopSong said:

Did you change the orifice in burner? I know that with some conversions you have to change that part out. However.. I have no idea whether the orifice is larger or smaller than for LPG. But, from >> THIS << article.. looks like it's larger.. and THAT may well explain your problem..

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Looks like he has the NG conversion kit (I see the needle valve in the vid). Maybe the LHBS he got it from tossed in the wrong orafice though. Might be worth comparing to the LP one to see if it's bigger or smaller. The NG one should be larger since the pressure is less.

A needle valve is just that. Simply a valve. This is a secondary valve that throttles the gas at the burner. However.. it does nothing to supply the proper mixture and volume at the burner. He needs some info on where to purchase or how much to enlarge the orifice on his current burner.

My suggestion would be to go >> HERE<< It is a slightly different discussion.. but, has a lot of pertinent information.

HopSong said:

A needle valve is just that. Simply a valve. This is a secondary valve that throttles the gas at the burner. However.. it does nothing to supply the proper mixture and volume at the burner. He needs some info on where to purchase or how much to enlarge the orifice on his current burner.

My suggestion would be to go >> HERE<< It is a slightly different discussion.. but, has a lot of pertinent information.

Click to expand...

Right, sorry I wasn't really referring to the needle valve as an orifice. I meant that Blichmann sells a kit with the proper orifice and a needle valve. It looks like he has the needle valve from the kit, so I assume he has the proper orifice as well since it's included in the kit. I was trying to say that maybe the supplier included the wrong orifice in his NG conversion kit.

Here's the kit I'm referring to for the Blichmann Burner NG conversion kit.

http://www.midwestsupplies.com/blichmann-natural-gas-conversion-for-toptier-floor-burner.html