Drop flue pan operation/cleaning

[Pete S]

We're considering taking the plunge and getting into a drop flue pan. We're "flat panners" so when I think about cleaning those dropped flues, as well all the "lost sap" that must be retained in them.

1.) What is done with the dropped flue pan when "you're done" with getting all the partially cooked sap out? I am going to assume it is simply collateral damage and simply dumped.

2.) I know how dirty our flat pan gets. How does one clean down into the flues. (syrup side and sooty side) I think a power washer may be needed, but then you'd probably need a brush as well.

Thanks

[n8hutch]

This is the down side to a drop flue. If you had a raised flue you could Isolate the front pan from the back pan, drain the flue pan & finish the sweet in your front pan while boiling water in your back pan. if you don't have a way to do that with your drop flue , you could always drain the whole rig & finish on what you used last year. If operated properly most times your flue pan raised or dropped won't get nearly as dirty as your syrup pan. People who run concentrate/ an R/O will tend to have more buildup than a guy running 2-3% sap.

[Schiefe4]

1) If you have access to RO water you could always push the sweet. I've done it before with regular water from the well. Well water probably adds a little something to the finished product so that last bit was saved for "friends and family" not for resale.

2) A vinegar soak and scrub always seem to work fine for the inside of the pans. Larger brush for front pan and smaller flue brush for flue pan. The outside of the pans I like to use a different type of flue brush each day before firing. Keeps the flues somewhat clean. At the end of the season I use EASY-OFF heavy duty oven clean and power-wash. Or if you know a dairy guy they have some nice stuff to clean stainless as well.

Here is a link for some of the different style brushes:
http://www.sugarbushsupplies.com/2014_Catalog/evaporatorparts.pdf

[Sugarmaker]

These folks nailed it:)
We chase the final syrup with water to the front pan and just keep boiling the syrup will mostly stay ahead of the water and the waste is less.
Yep brush to fit the inside of the flues and a brush with handle to fit the fire side of the flues to remove soot as needed.
Good luck with your dropped flues. I have been boiling on them for 30 years.
Regards,
Chris

[lpakiz]

I found a round, stiff-bristled brush in the dairy supply section. It's maybe an inch in diameter. I cut the handle off and chuck the twisted wire stem in the cordless drill. I use the "sour sap" method, and let it set about a month. Then drain the vinegar out and hose it down, scrubbing with the drill as needed.

[vtmapleman]

My brother-in-law has a drop flue 6x16...He has a plug to put into the front pan feed line, drains all the sweet from from the back pan into 50 gallon barrells, fill the back pan with water and feeds the front pan with 5 gallons of sap at a time...works for him.

[Big_Eddy]

We're considering taking the plunge and getting into a drop flue pan. We're "flat panners" so when I think about cleaning those dropped flues, as well all the "lost sap" that must be retained in them.

1.) What is done with the dropped flue pan when "you're done" with getting all the partially cooked sap out? I am going to assume it is simply collateral damage and simply dumped
2.) I know how dirty our flat pan gets. How does one clean down into the flues. (syrup side and sooty side) I think a power washer may be needed, but then you'd probably need a brush as well.

Thanks
See this thread for a similar discussion Logistics-of-emptying-flue-pan-after-every-boil-for-weekend-warrior (http://mapletrader.com/community/showthread.php?24066-Logistics-of-emptying-flue-pan-after-every-boil-for-weekend-warrior)
I lose no sap during the season. When needed, I isolate the flue pan, siphon the sweet out of the flue pan into pails, then add it to the syrup pan to finish off.

The Flue pan doesn't get very dirty inside - most of the nitre forms in the syrup pan. I clean my flue pan at the end of each season only, using a vinegar wash and a green scrubby if needed. The outside gets a good scrubbing with the pressure washer after the season. A brush between the flues during the season will remove soot and improve heat transfer. My evaporation rate drops from boil to boil as soot builds up, so a brushing every boil or 2 is recommended. Some use a stiff brush on a broom handle to get in between the flues.

[maple flats]

Even with a raised flue, I do the same as most above. When the final sap from the head tank is gone, I drain the flue pan into a barrel. Then I pump the head tank full of potable water, close the valve between the flue pan and the syrup pan and boil again. I keep transfering concentrate from the barrel to the syrup pan at about 2 qts at a time. As the syrup pan boils down enough (with the barrel empty) to get to about 1" deep, I let the fire go out. When out, I draw the near syrup into my draw off tank, and pump it to my finisher.
The only difference on a drop flue will be if it does not have a low (near the bottom of the flues) drain, you will either siphon the last bit, or just flood the pan with water and abandon what little is in the flues. Most newer drop flue pans have a drain that ties the flues together and drains out the side.

[VT_K9]

About 4 years ago we looked at replacing our tin rear raised flue pan with a new stainless steel pan. While looking at our options we found that we could get a new evaporator with drop flues for just a little more than a rear pan. After boiling on the pan we find that we have to siphon the flues out. The rear pan does not get that dirty due to the heavy boiling action. I try to run the brush between the flues prior starting the fire every day. As mentioned before this helps keep heat transfer as high as possible.

At the end of the year we have used vinegar and last year we let some permeate sit (we did cycle it through with a low volume pump) in the pan for a couple weeks. Both seemed to work well with very little scrubbing.

Good Luck,

Mike