Help! Probs hitting target mash temps

Perhaps I'm missing something here, but when I change the specific heat for my mash tun, it doesn't change the infusion water temp.  I'm missing my mash temp by around 5 degrees.
 
I have a stainless keg that is insulated with 2.5" of spray foam.  I've tried a specific heat number of 0.12, the recommended stainless value, and also .3, which is recommended for plastic coolers. The mash tun weighs about 40 lbs. 

I don't have any idea what specific heat is, or what to set my value at, and last, it doesn't change the temp of the infusion water when I change the values. 

Thanks for your help,
Dave

Specific Heat is an expression of the energy required to change the temperature of a substance. Typically, one degree, as a function of its mass.

If you are changing Specific Heat in the Profile tab, it won't effect the recipe until you import it into the recipe. Otherwise, changing the profile within the recipe is what you want to do. You also have to have the Adjust Temp for Equip box checked in the mash tab.

You can find the exact specific heat of your mashtun with the Mash Adjust tool and a floating thermometer.

Accurately weigh your mashtun.
Accurately measure out 3 gallons of water.
Heat the water to 170 (actually, any temperature will do, but this is closer to brewing).

In the tool:
Starting Water volume: 0
Weight of grain: 0.0001
Starting mash temperature: ambient temperature of the room
Weight of mashtun: as weighed
Mashtun Specific Heat: 0
Water Addition Temp: 170 or the exact temperature you use.
The mash water ratio will read something crazy. Ignore that.

Quickly add the heated water and floating thermometer to the mashtun. Cover and wait 5 minutes.
Read the water temperature.
Input the water temperature as "Target Mash Temperature" in the tool.

Now, simply change the Mashtun Specific heat until the "Water Volume to Add" matches 3 gallons.
That's your mashtun's specific heat!

Thanks Brewfun!

I'll follow your excellent instructions and report back.  I'd sure like to use BS and hope to get the settings understood and accurately adjusted to our equipment. 

Dave

Simply out of curiosity as I do like to dial in my equipment.  Should this process be followed by most of us?  Or, if I have a converted cooler no matter what brand and size, I am good to go?

I don't think it hurts to check new equipment for accuracy's sake. It may be that specific heat for most coolers are close together but the point of the software is accuracy. The more accurate the parameters it has, the better.