Niter building

[jimbison]

I have a terrible niter build up in my pans during sugar season some of the basic info on my setup
4x12 Thor evaporator
4x8raised flue 4x4front
1800 taps plus 500 on halves for neighbor
Concentrate to 6 or 8 percent
I can only boil for about 2 hours before having to switch sides because of the niter building is so bad, some days only making about 30 gallons before switching
Any ideas how to get more time before switching or anything I might be doing wrong

[n8hutch]

How Hard is your boil? How many years has this been an issue? Some years the Niter is considerably worse than others. I would think that you should be able to fill a Barrel before you switch. Have you ever burned any niter on? Maybe you are switching a tad early because you're nervous? Can't fault you for that.

[maple flats]

What basis are you using to tell you when the niter is built up?
I also have a Thor (set of pans), each year and even at different times during the season niter will be vastly different. I control mine by using a nylon spatula. With that, I test the bottom of the channels by holding the spatula so the blade of it contacts the bottom of the pan at about 45 degrees, I then pull it across the bottom, if it slides easily, no build up, if it has resistance, there is niter. Once the resistance when being pulled gets to be medium in the draw off channel, I reverse the flow. In my experience niter will first show in the draw off channel. At that reversing the flow helps, but the time it will take to need cleaning will be sooner than it took to build up the first time. If it took 2.5 hrs for the 1st test to need to reverse, it might only be 1.5 or 2 hrs on the opposite flow. I also find that the previous draw off channel will either clean up in use or at least get better.
This has almost always gotten me thru a day's boil, but sometimes I need to shut down mid boil and clean. That happened 1 time in 2019, no times in 2018. I find if you reverse soon enough and sometimes even reverse back again I can finish.
That being said, I concentrate to anywhere from about 7% up to likely 13%. I was boiling (in 2019) on a 3x8 and 750 taps. My pans are 3x3 syrup and 3x5 flue with 10" raised flues, plus I have a pre-heater so the sap hits the cold sap box at between 150-175F, except at the end of a draw off, at which time it might drop to 110-120F.
While the concentrations I gave are a range, most sap enters the cold sap box at 10-12% and about 160F.
Does any of this info help? Ask questions if you need. At times I also take sap on shares from 200 up to 600 extra taps.
Also, some years niter is far worse or totally of different character.

[maplwrks]

Nate and Dave have got it covered. I drain and clean my evaporator every night. (especially the syrup pans) After I drain and filter everything in the syrup pans, I fill the pans with permeate. Sometimes, This alone will eat the nitre off the pans during the over night. I also use a 1/6 hp submersible sump pump that I put right into the syrup pan. On the pump, I have attached a short "gooseneck" of pvc pipe to and allow the pump to run all night while blasting the permeate onto the bottom of the pans. This has proven to be the best way for me to clean my pans , short of purchasing a pan washer. The pump creates a lot of turbulence in the pan, and the pans are nitre free in the morning.

[jimbison]

I check the niter build up with the scoop feeling the bottom of the pan.last year we drained the front pan nightly and washed it with a acid cleaner just using permiate wouldn't do it.i have always had a lot of niter just not that much that I had to shut down and clean it so often I have a chance to take an additional 1000 taps of a neighbor and trying to figure out how to run more before having to shut down.knowing that the bigger producers are making hundreds of gallons before cleaning I thought I could improve the length of my boiling time before cleaning thank you for your wisdom

[maple flats]

jimbison, I suggest you test using a nylon spatula rather than your scoop. The scoop has a hard SS edge and could scratch the bottom. Scratches can also lend an anchor for niter to attach to the bottom.