Burn Baby Burn

Posted by Tim Vandergrift on

Propane burners are excellent for heating hot liquor (brewing water) or boiling wort. They vary by model, but run between 30,0000 and 140,000 BTU's. To put this into perspective, your stovetop burners at home run about 7,000 BTU's--and take forever to boil 25 litres of water. A propane unit in tiptop shape can boil 25 litres in under 15 minutes, making your brew day far more efficient.

Of course when you're burning that much propane, that fast, you need to make sure you've got good ventilation and that the burner is in an area where a very hot, open flame isn't going to be a danger. You also need to check your connections and hoses before you fire it up, to make sure everything is safe and free of leaks.

Occasionally a burner won't fire properly, and then it's time to troubleshoot. Always check to make sure your propane tank is full first--simplest fix of all. After that, make sure your regulator is reset properly: many regulators have a safety feature that disables gas flow if the burner valve is opened before the tank gas valve. This protects you from unexpected flare-ups, but the burner won't light until you shut off both valves, disconnect the gas hose from the tank to release the pressure, reconnect everything and open the tank valve before opening the burner valve to light it. 

It's also important to have the right fuel-air ratio. Too much air and you get wispy blue flames that want to blow themselves out. Too much fuel and you get leaping orange flames up to the ceiling. While that looks impressive, the flame is sooty, and much cooler than a good blue flame that's much smaller. 

Last week at Fraser Mills we had a more serious problem. One of the burners we were using for the Verruktes Donnerbrau Festival got knocked, and the needle valve snapped off.

Replacement valves are available but they're $15 USD and just as fragile as the original unit. We can't be sure why the manufacturer chose that particular valve because there's already a shut-off on the gas line, and the second needle-valve is redundant. 

What you can do is disconnect the whole valve like this:

Step one is to toss away the needle valve and the union that connects it to the hose. Step two is to grab a connector that goes from the hose to the burner itself, without any of the delicate little needle valves. Important to this is to get a connector that has the right sized orifice:

 

Not tiny

There are brass (phosphor bronze, actually) connectors that are used for CO2 lines to attach to swivel nuts that look great and fit, but the orifice is far too large.

Tiny

Properly sized orifices seem ridiculously tiny for the kind of gas volume and heat you want to generate, but look what happens when you use the bigger version: 

 

Whee!

Next, wrap that baby in teflon tape. Since these are tapered threads and they're designed to gall up and make a good seal, teflon tape is not considered necessary. But we do it anyway because it's cheap and potential gas leaks give us the heebie-jeebies. 

Insert the valve, tighten it down, connect the hose and it's ready for a test-firing. 

Although not nearly as dramatic as the big-jet flame, it's a lot hotter, and vastly more efficient. Job done, and we're ready to brew again. 

If you have any questions about your burner, or you'd like to look at one of the ones we have here at the store, give us a call. 


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