On my Smoky Lake WJ bottler, I have it set up with a site tube for the water level. I ran a 1/4" T coming out of the drain fitting and put a 1/4 MPT x 5/16 barb fitting pointing up, then a close nipple and a ball valve to drain the water jacket. On the barb I put a piece of 5/16 maple tubing. Near the top I used some super sticky tape which holds it from tipping. The site tube helps me know the water level. I fill it until the water reaches the top of the tape. Then when it is heated it is up about 1/4" above the tape and is still about 1/2" below overflow.
Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.