Using a Blichmann floor burner oustide i the cold.

So this past weekend my buddy and I were using our blichmann burner for the second time. After using it for the strike and sparge water fine, it back fired by the hose. I was wondering what may have caused this. It happened three times before we brought out the old turkey fryer burner. Some more background info: 46 degrees, tank was starting to to freeze up but worked fine for the other burner(I'm guessing lower pressure) and the wind wasn't too crazy. Any help would be greatly appreciated.

Sorry, after the strike and sparge water were fine it back fired shortly before reaching the boil.

Deleted repost.

I don't know what you mean by backfired. Would you explain it another way, please?

I expect he means he saw flames in (and maybe shooting out of) the venturi bell. I run a pair of those Blichmanns and have never experienced that, but I've read of it happening.

Assuming it's not a leak at the crimped-on hose coupling (that's also been reported here at least once)...and given that the floor stand design pretty much precludes insufficient burner-to-pot clearance...and that the burner managed to get through heating up the strike and sparge water without issue... I would guess there wasn't enough gas volume flowing through the burner (perhaps due to that freezing tank) so it back-fired through the venturi.

I can get the same thing to happen when I shut off the gas at the end of a session, but it's just a "pop"...

Cheers!

I'd return it... personally.

day_trippr said:

I expect he means he saw flames in (and maybe shooting out of) the venturi bell. I run a pair of those Blichmanns and have never experienced that, but I've read of it happening.

Assuming it's not a leak at the crimped-on hose coupling (that's also been reported here at least once)...and given that the floor stand design pretty much precludes insufficient burner-to-pot clearance...and that the burner managed to get through heating up the strike and sparge water without issue... I would guess there wasn't enough gas volume flowing through the burner (perhaps due to that freezing tank) so it back-fired through the venturi.

I can get the same thing to happen when I shut off the gas at the end of a session, but it's just a "pop"...

Cheers!

Click to expand...

I don't know what the venturi bell is (and google didn't help) - is that the piece where you control the air/oxygen flow?

I also get a 'pop' when I turn off the gas, but have never paid much attention.

Stick the tank in some warm water and see if it still happens. I have to do this on a cold day to keep the pressure up some times.

Pappers_ said:

I don't know what the venturi bell is (and google didn't help) - is that the piece where you control the air/oxygen flow? [...]

Click to expand...

The piece that controls the air flow is a damper. The damper covers the mouth of the bell-shaped induction manifold. The pressurized gas passing through the flare fitting in the center of the damper pulls air through the damper openings, a phenomenon caused by the venturi effect - which occurs within the "bell".

Not all of the required make-up air for full combustion at the nozzle tips is provided via the induction system - additional air is required at the nozzle tips. If this wasn't the case you'd always have a roaring fire within the manifold (not good).

When the gas flow declines too far the air/fuel ratio within the manifold will approach the level required for combustion, and you'll get the "back fire" effect.

Thus I expect this was yet another case of the contents of the propane tank getting so cold the evaporative pressure dropped too low to maintain the excessively rich air/fuel ratio within the manifold, and it lit up...

Cheers!

Pappers_ said:

I don't know what the venturi bell is (and google didn't help) - is that the piece where you control the air/oxygen flow?

I also get a 'pop' when I turn off the gas, but have never paid much attention.

Click to expand...

Did you notice that the "old turkey frier" saved the day? I love those things. 60,000 btu of reliable, cheap heat.

I appreciate the input guys. I think a pot of warm water with the tank sounds like a good idea. It didn't really start happening until the tank started frosting.

I've seen when the tank gets low and frost is developing on the tank. I believe it's being cause by a drop in pressure.

I wonder if a fermentation warmer on the tank would alleviate the problem on cold days? Has anyone tried that?