Freezing flues

[lyford]

Cooking on the 2x4 drop flue as I type this. Gonna get down to around 20 degrees tonite and 10 degrees tomorrow nite. Pans are not sweet yet, can I leave eveything outside with out worry or should I roll it back into the garage.

[motowbrowne]

Cooking on the 2x4 drop flue as I type this. Gonna get down to around 20 degrees tonite and 10 degrees tomorrow nite. Pans are not sweet yet, can I leave eveything outside with out worry or should I roll it back into the garage.

If it's as easy as rolling it into the garage, that's what I'd do. Another option would be to plug in a lightbulb in the firebox. That should put off enough heat to prevent it from freezing.

[Maple Man 85]

Play it safe and roll it back in, freezing liquid expands and there's chance you may damage the pan. Otherwise I've heard of people putting a light (or anything that generates heat) in the fire box because its easier than draining the pan(s).

[ecolbeck]

Does anyone out there have actual experience with freezing causing damage to a pan? As the water turns to ice and expands it has plenty of space to move. Even in the flues the ice can push upwards.
In addition, the presence of sugar in solution depresses the freezing point.

[BAP]

In 45+ years of sugaring, I have never seen nor heard of a flue being damaged from freezing. Not to say it couldn't happen, but if the sap has been boiled at all, there should be enough sugar in the pan to keep it from freezing rock hard.

[lyford]

Well I played it safe, and evaporator is in the garage. I am also interested to hear if anybody has had any experience damaging a flue by letting it freeze.

[Michael Greer]

Ice expands at 10,000 lbs. per sq. inch, so if you trap it, something will break. A sweetened pan may not freeze...just like the glycol in your radiator...but it might if it gets cold enough. It would be an expensive experiment.

[Brian]

Yes it has happend,there have been other discussions about this years ago. I think some one had there drain tube break. I belive sweeted pans are good to 0 'F

[Maple Man 85]

Did some research yesterday thanks to mother nature... I shut down around noon yesterday after boiling 100 gallons on a 3x4 flat pan 20 acres back in the woods in a non-insulated sugarhouse. The temperature was 3 degrees this morning and what I had in the pan would have made a nice maple brandy slush but it was not frozen solid.

[lyford]

Well that's good to know, thanks for the info.

[mudr]

I just put my heat lamp that I use for baby chicks in my firebox. Pan was fully sweetened at shut down, and I do not have plugs to prevent mixing. So, all the pans are now a mid-level of sweetened. It's already frozen over on top, I hope this helps to prevent any problems. Might light a quick fire sometime midday tomorrow to fully thaw, then put the heat lamp back in once all the coals are gone.

[bowtie]

I have not checked my pans since Wednesday, but I doubt it will be an issue, I left a lot of sweet in and let it back flow into flue pan.If the liquid/ice has a place to expand it should not split anything. That said it could expand enough I guess to split welds on the flues but I doubt it.

[MapleMark753]

Ice expands at 10,000 lbs. per sq. inch, so if you trap it, something will break. A sweetened pan may not freeze...just like the glycol in your radiator...but it might if it gets cold enough. It would be an expensive experiment.

I have not had flues freeze or had damage from that. I HAVE had two valves burst from freezing, one a 3/4 inch and one a one inch. Both were on the evaporator, and both were left closed for just a few hours (overnight) by me. Didn't like that.

[Jmsmithy]

Being in the Adirondacks it gets cold. Real cold. I never leave anything in my pans when I know it's getting cold that night. I know what I paid for those pans and would hate to buy them again. Not worth the little bit extra time it takes to empty imho ...

[Buddy 58]

Depends on how cold it gets for me . But with it getting down to around 0 to night I lit a small fire in the evap yesterday , and let the whole thing empty out . AS said before ( $ )

[SeanD]

Just curious how long after the fire is out you wait to drain the pans. I'm always afraid the residual heat from even a small fire will warp an empty pan. So, I usually do one or the other - fire or drain, (or stick a lamp in there like I have now).

[maplefarmer]

I put a small [milk house ] they call it heater in the firebox, and shut the door, has a temp. knob on it so it won't be on all the time like a light bulb would be.

[maple flats]

I've never worried at 5 F or above, but the forecast called for -5 F last night. In the past, when below +5 I used a 100 watt bulb but last night I tried another way and it worked fine. I use a 500,000 BTU weed burner torch to light my fire when starting the evaporator, last night I used it (fueled off a bulk propane tank) and I turned it as low as I though would remain lit. I went to check this morning and it was good, the auto draw showed 52 F when I turned it on and the flue pan felt about the same temperature. When I did that I closed the door with the head of the torch just inside the firebox. The flame was shooting out about 4-5" from the torch head. I also checked the fuel gauge on the 50 gal bulk tank, it read the same as last night so it did not burn enough propane to make the gauge move. I did later have a thought cross my mind, what if the torch goes out but there is still a little propane going into the evaporator and that get ignited when I turn on the sugarhouse lights. Thinking that, I did not turn the light on til after I saw the torch was still going. I'm thinking in the future I might rig a small heater with just a pilot light on and adjust the pilot light a little higher than normal but leave the valve on pilot only. I think that would also work well and be safer too. I feel safer with the dependability of propane that if on electric and a drunk runs over a pole and I'm without electric for a few hours. I do have solar and part of the system is on battery back up, but I'm already using that to heat the RO room as back up and those 7 yr. batteries are now 9 years old.

[Dave Puhl]

I also had a 1'' ball valve bust the housing during the off season can't remember if it was open or closed but the small amount of water between the ball and housing is what cracked it..it might have been open?

[325abn]

I drain my flue pan when it's getting really cold like now, if my syrup is really sweet and close to syrup I will just let it be.

[Buddy 58]

Just a small fire , just enough to thaw things out . let the fire burn out , start draining , doors and draft open drawing in cool air . Been doing this for years . I run a 3x10 grim lighting , another thing I do after every boiling day is all fire and ash is cleaned out - evap is cooled down before I leave the sugar house , I have two farms , sugar operation is not on the one where I live . By not letting the grates sit in hot ash and coals I have never had grates warp . And when I leave I worry about nothing .

[Wanabe1972]

I pull the float out of the box and run a clip on light down almost to the SAP and one in the firebox. It never got above 18 yesturday and was 0 last night. When it got home from work at 7 am my house water was frozen. After fixing the house I checked the evaporator and it had a layer of icey slush on top but I stuck my finger into perfectly thawed flues.

[abbott]

After two nights around zero and a cold day in between, my flue pan (40"x7') was all iced up, but I found no leaks when I thawed it this morning. In hindsight maybe a lamp in there overnight would have been good - I have no electricity down at the sap house, which is a half mile from the road. Sometimes I drain (or at least mostly drain) the flue pan for weather like this and bring the sweet up to my house in 5 gallon. But maybe this head cold was affecting my judgement.