best way to shut down and fire up evaporator

[Sly41985]

just a quick question wondering how people shut down and fire up their evaporator every time. i am currently using a Leader 2x6 wse model. At the end of the night i draw off some"sweet" and then flood the pans about 2". unfortunately everything mixes between the flue pan and syrup pan because i do not have a shut off between the 2 pans. when i started the evaporator up i add the "sweet" i drew off to syrup section. the thing i noticed about this past shut down was how their was a lot of what looked to be niter in the flue pan. i didnt think this was suppose to happen. so just wondering if i am doing something wrong. Thanks for the help i do appreciate it!

[DrTimPerkins]

Niter in the flue pan is not at all unusual. In your case, I think I would add either a valve or a plug between the flue pan and syrup pan to prevent mixing. This would help maintain your gradient better between boils and allow you to reach draw-off sooner during your next boil. Are you flooding the pans because of residual heat? Is the sap coming to a boil again before cooling off? If not, you risk developing ropey sap/syrup in your pans.

[mol1jb]

This is only my first year with a new used 2x6 but here is what I have been doing. I stop feeding wood and flood the flue pan with sap so it can boil a bit while there is still heat. Then I push the sweet out of the front pan into a draw off container and refrigerate overnight. Once the sweet is out of the front pan I am able to flush with water any niter that has accumulated to have a nice clean front pan. The next morning I drain the water and put back the sweet into the front pan from yesterday. Yes the sweet in the front pan has to form gradient again but that just makes for a few long draw offs early in the day so no worries there. But I am also able to shutoff between the front and back pan so this system works well for me.

[Ghs57]

There is no valve between my flue and syrup sections on my 2x6. I do not draw anything off or flood the pan. My rig takes a few hours to cool down, so I come back and check things then, and shut off the head tank (my float does not always completely shut down the flow from the head tank). Yes I loose the gradient, but in the hour or so it takes to reestablish after a restart is when I gather/split wood for the day, transfer sap from the truck to the holding tank, fill the head tank, etc. For example, yesterday, after the gradient reestablished, I had an almost continuous slow draw-off for around 5 hours.

Since everyone's setup and conditions can vary, I think that over time we find the method that works for us.

[Big_Eddy]

Like Gary - I don't do anything special.

I confirm that the syrup in the front section is not close to draw off density, and stop firing.
I leave my feed line open to the float box and stay close by for at least 30 minutes (4x firing interval) while it cools off a bit.
By that time, my float box has usually caught up and the depth in the pans is about 1/2" deeper than under a full boil, and the pans are simmering and I'm safe to leave.
I'll come back about 1/2 hour -45 mins later to close all the valves, close the ash door, and close the cupola vents.

When I start up, I leave the feed valve closed until I have both pans boiling then I open it up and run full bore. My first draw is usually a bit longer and a bit larger and then it settles to a draw an hour.

[mellondome]

On my 2x6 raised with natgas, I turn off the burners when the head tank empties. Then shut valve between pans and draw half the remainder of the syrup pan off into a bucket. Drain the preheater into the flue pan. Draw the remining front pan into a seperate bucket. Flood the front pan with permeate. Draw the flue pan into my drawoff tub and run it through the filter press. Flood the back pan with permeate. Turn burners back on to bring permeate to a simmer and then shut down till next boil.
On fire up, I pump back pan contents from the previous boil back in the pan. And put the second draw from the front pan back in the front pan. Open the headtank valve. Light the fire. As it starts to simmer in the front pan, i put the remainder of the front pan contents (first saved from front pan ) back in through the drawoff box. And open the valve between the pans.

[WESTMAPLES]

just a quick question wondering how people shut down and fire up their evaporator every time. i am currently using a Leader 2x6 wse model. At the end of the night i draw off some"sweet" and then flood the pans about 2". unfortunately everything mixes between the flue pan and syrup pan because i do not have a shut off between the 2 pans. when i started the evaporator up i add the "sweet" i drew off to syrup section. the thing i noticed about this past shut down was how their was a lot of what looked to be niter in the flue pan. i didnt think this was suppose to happen. so just wondering if i am doing something wrong. Thanks for the help i do appreciate it! ive been running the same evap for 6 yrs now great unit , i do that same draw off some syrup / almost syrup before shutting down mostly in the low between firings. then fire it 2 more times before setting the float for 1 3/4 in deep fire it good 1 last time , close the valve between the pans ( add it 2 years) once the front pan makes it up to 1 3/4 mark , then walk over and shut the head tank off ( if its not almost empty already), and then drop the float arm all the way down so it drains out most everything from the head tank thru to the float box, and still have a good boil front and rear so the float box gets up to temp upon complete shut down. most of the time when i start up the front pan is down to 1 in already from the previous cool down, so i reset float at 1 in, open head tank valve, fire it up hard and at the first sign of a good constant boil in the front pan , i open the valve between the pans and off i go again . i always saw and used the hot start and hot stop method because it made for less heavy soot build up on the bottom of the pans and less bacteria from unboiled /sanitized sap in the flue and float box, if all that makes sense . long short.... its hard to make easy fast start/ stops with no gradient mixing without a valve or stopper between the pans , i lucked out and saw bascoms had a nice used valve setup to fit the leader wse so i made a trade with them for it. i think leader sells a valve kit but it wasn`t cheap, maybe a pan plug would be cheaper, but i have no experience with them .

[VT_K9]

We have been running a Leader WSE 2X6 for the last 10 years. It is a decent unit for what it is. We have not installed a valved between the back and front pan. We use a silicone stopper to keep the contents separate. A fresh start is a fresh start...keep boiling. At shut down we have a mark on the head tank for last fire. We try to have a few gallons of sweet to draw off at the end to aid in resetting the gradient in the front pan the next day. Upon the next start up we are boiling the sweet we drew off to help make it denser. We then bring the arch up to a boil (keeping the stopper in place). When the sweet and front pans are as hot as they are going to get we add the sweet (still keeping the stopper in place). We try to maintain about 1 1/2" in the front pan. Once everything is settled we open the head tank and then remove the front pan stopper. Then in a short bit start drawing syrup off.

Mike

[motowbrowne]

When I start up, I leave the feed valve closed until I have both pans boiling then I open it up and run full bore. My first draw is usually a bit longer and a bit larger and then it settles to a draw an hour.

I do this too, but it's extremely important to make 110% sure that the feed pipe is operational. You don't want to get everything rolling and approaching the optimal depth only to open the valve and realize your line is frozen or something.

[Big_Eddy]

I do this too, but it's extremely important to make 110% sure that the feed pipe is operational. You don't want to get everything rolling and approaching the optimal depth only to open the valve and realize your line is frozen or something.

Good point.

Part of my pre-lighting check is supposed to include filling the emergency pail then pressing down the float and confirming flow.

Gets exciting when you open the main tank valve and nothing comes into the float box. That's about the time I realize the oh **** pail hasn't been filled yet.

[Ghs57]

Good point.

Part of my pre-lighting check is supposed to include filling the emergency pail then pressing down the float and confirming flow.

Gets exciting when you open the main tank valve and nothing comes into the float box. That's about the time I realize the oh **** pail hasn't been filled yet.

I'm always afraid I'll forget to open the head tank, so I do that first before I light the fire. All valves open.

Nothing like reaching for an empty OSB! Or, remembering you left it out by the holding tank! Then your day is about to become much more interesting.

[Sly41985]

Thanks for the info guys i do appreciate it!!!