motor driven water pump for cooling a still

Using Arduino Programming Questions
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Hi all New Bee here,

i have a temp sensor that will monitor the still temperature and will turn the pump on/off with pin 6 PWM driving a FET.

My problem, The PWM seems 25% on or fully on , nothing in between. would like so is slow then get faster, or fast then slow down , but my PWN

I my code below, it is a mix of my own and some else s i have modded
any tips?

test.doc (31.5 KB)

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Is a PID really essential for maintaining temperature on something as large as a still?

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