Temp sensors

[nwomatt]

So I'm in the process of getting my 2-500 gal lp tanks set. I've got them stacked and welded and have a few minor leaks (welds) to mend. I had a real rough time getting some of the plugs to seal up enough to hold 40 lbs of air. Got it now. Was wondering if I want to monitor top and bottom temps can't I just fix the sensors to the outside of the tanks instead of using wells and going through the same leak issues?

 

[ewdudley]

if I want to monitor top and bottom temps can't I just fix the sensors to the outside of the tanks

Sure, there would just be more time lag, which is not a problem. You may prefer to have the sensors placed so you can tell better how much hot water is currently stored. For instance I have three sensors at roughly the 1/4, 1/2, and 3/4 points, which tells me how soon to light a fire and how big a fire to light.

Some guys use system pressure to tell how much hot water they have since accurate system pressure will correlate very well with how much heat is in the tanks.

 

[jebatty]

Right on. I use aluminum duct sealing tape which is very sticky and heat tolerant, and then covered by the tank insulation. Here's a nifty calculator to determine how much water is in the tank at various levels.
http://www.calculatorsoup.com/calculators/construction/tank.php

 

[maple1]

So I'm in the process of getting my 2-500 gal lp tanks set. I've got them stacked and welded and have a few minor leaks (welds) to mend. I had a real rough time getting some of the plugs to seal up enough to hold 40 lbs of air. Got it now. Was wondering if I want to monitor top and bottom temps can't I just fix the sensors to the outside of the tanks instead of using wells and going through the same leak issues?

You can do aquastats without wells too. After my install, I would highly recommend keeping holes in tanks to the very minimum.

 

[Clarkbug]

Right on. I use aluminum duct sealing tape which is very sticky and heat tolerant, and then covered by the tank insulation. Here's a nifty calculator to determine how much water is in the tank at various levels.
http://www.calculatorsoup.com/calculators/construction/tank.php

Yup, I used the same tape with some thermal grease on it for good measure (round probe on a round tank....figure every little bit helps), then I stuck some sticky rubber insulation over the top of that. Works great, and if its off by a few degrees, no biggie.