need help with pid!

Okay, i (biodiesel guy) need to lean on the expertise of you home brewer guys. Our guys don't even know about PID yet! I have a 200 gal conical tank that circulates bottom to top. It has a 1/2hp pump and flows through an external steel box that contains a 5500 watt heater. I also use a 55gal drum that circulates oil through a 5500 watt heater fed by a 1/2hp heater into a small centrifuge. I bought 2 Sestos temp controllers and 2 Sestos dual timers. My goal for these pids is to control temps and use the timers as a simple on/off for the pumps and shut everything down after two hours of mixing in the 200 gal tank. In the 55 gal centrifuge tank after 6 hours. Is this possible? Like i said, you guys are light years ahead of us and i want to be among the first to do it!

There are PIDs with integrated timers that can open / close an alarm circuit. If you were to wire the alarm to a relay that controls your pumps, it should work to turn off the pump. Not sure if it'd turn off the heating element though...

It would be pretty straightforward to use a PID to maintain temperature and a timer to trigger an alarm. Alarm goes off, manually turn off the pump. Is this what you are looking to do?

Yes, that's pretty much what i need. PID 1 controls temps on tank 1. PID 2 controls temps on tank 2. Timer 1 to shut off pump 1 and maybe second alarm to cut power to heater 1? And tre same exact thing for setup 2. I believe the Sestos have powet off memory. If it's not too much trouble,could someone draw me wiring diagram with switches,alarms, and grounds??? My pumps are single phase, would it be better to keep the whole thing 120 to match pumps or is it possible to run 240 for the big heaters? I'd like to do 240 because heating 200 gal would be much faster.Also, i want to use one of your reflux columns on top of my processor to remove methanol vapors and condense into a container to recover excess methanol by vacuum. Please share your thoughts about this also. Thanks for letting me borrow your brains so i can be on the forefront in my industry!

My guess is that even with 2 twin timers, i cannot still have 'heating element on' light and 'pump on' light' because i will be using the alarm outs for other purposes.

What's the reason you all seem to prefer Auber over Sestos? It seems Sestos looks nicer.

vegoiltycoon said:

My guess is that even with 2 twin timers, i cannot still have 'heating element on' light and 'pump on' light' because i will be using the alarm outs for other purposes.

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I suggest that you use each PID just to maintain temperature, and perhaps to trigger an alarm if your temperature strays to far from the setpoint. Use the timers also to trigger the alarm when time is up. You can use a single alarm buzzer/light. That, any other other switches or indicator lights would be powered separately from the PIDs and timers. For example, to have an indicator light illuminated when the element is on, you would wire a 240v LED in parallel with the element.

What electrical service do you have there? Even 5500w at 240v is going to take a long time to heat up 200 gallons. What temperature are you trying to achieve?

You should be able to run dual 240v/120v using one of the 240v hots and the neutral, assuming you have a 4-wire (H-H-N-G) feed.

Have you read through www.theelectricbrewery.com? Study that and you will have a much better understanding of how to approach this.