Idea for Homemade EKO stove Control

[deerefanatic]

Ok guys, I've got a diagram here for you to follow my logic on...

For Controllers I'm thinking of using these controllers on eBay: (broken link removed)

They seem to be quite popular with the homemade espesso machine crowd and get good reviews...

Now, here is my idea: Statements are numbered...

1: If temperature A is greater than 400F then the fans on the stove will be slowed to half speed to slow down combustion and allow the water more time to absorb from the exhaust.....

2: If temperature A is less than 225F then the water pump will be shut off to allow the stove to catch up and keep the gases from condensing in the heat exchanger..

3: If temperature B (water temp in heat exchanger) is greater than 175F then the water pump will turn on to circulate water.

4: If temperature B becomes greater than 190, then the fans will be shut down to protect from boil-over. This will override instance 2, so if temperature a is less than 225F, but temperature B is greater than 190, the pump WILL still run and the fans are shut down. It's more important to keep away from the boiling zone than to have exhaust gases condensing.

5: If temperature C becomes lower than 350F then the entire stove (fans and pumps) will be shut down. This is to keep a bed of coals in the stove for easier start up on next load. There will be a latching relay circuit attached to a "start" button that will override this control to allow stove to be started.. Once temperatures exceed 350F, then the start circuit will be canceled and stove control will be taken over by the end-of-burn circuit (Temperature C)

What do you guys think? Do I have my temperatures right and all? I'd appreciate any feedback you all have.

 

[deerefanatic]

Hmm.. I reallllyyyyyyyyy need to get ahold of someone with an EKO or something similar to measure dimensions from.

What about the the electronics parts?

 

[Nofossil]

Hmm.. I reallllyyyyyyyyy need to get ahold of someone with an EKO or something similar to measure dimensions from.

What about the the electronics parts?

Looks like it's a PID (Proportional/Integral/Differential) controller with a single thermocouple input. Good for controlling an output to maintain a value at a setpoint (oven temperature, for instance) but not for more complex control of multiple devices based on multiple temperatures. I haven't studied the manual, but that's my take on what it is.

 

[deerefanatic]

Yah, they're a PID. They have two alarm outputs that can be set to come on above/below a certain temperature.... Those are what I was planning on using actually, and not doing anything with the control output.....

I was planning on using 3 of them, one for each of the temperature areas I outlined in the first post....

 

[Nofossil]

Yah, they're a PID. They have two alarm outputs that can be set to come on above/below a certain temperature.... Those are what I was planning on using actually, and not doing anything with the control output.....

I was planning on using 3 of them, one for each of the temperature areas I outlined in the first post....

That makes more sense. You'll need a bunch of relays to implement the additional logic, but that's OK.

Here's a shot of my control panel. It's grown a bunch more relays in addition to the ones you can't see behind the switches and under the hood of the EKO.

 

[deerefanatic]

Very nice......

Yah, if I had the brains to program my own controller..... I'd do it in a heartbeat.... It'd be cheaper, more integrated, and more flexible too....... I could even use PWM to control the speed of the fans and make the boiler into a modulating boiler.... Oh well......

 

[Nofossil]

Very nice......

Yah, if I had the brains to program my own controller..... I'd do it in a heartbeat.... It'd be cheaper, more integrated, and more flexible too....... I could even use PWM to control the speed of the fans and make the boiler into a modulating boiler.... Oh well......

I started out with just relays and thermal 'snap' switches. It was just to help me relax. Before I know it, I was doing schematics and ladder diagrams far into the night, abandoning my friends and family. I kept telling myself that I could quit any time, but it was too late. Pretty soon I was into the hard stuff - embedded controllers, ASICS, cross compilers, the whole works. I was alone, tolerated at best, but usually pitied or ignored. I'm reduced to begging now - struggling to find enablers - folks who will toss me a scrap of recognition or appreciation.

Stop now, while you still have a chance for a normal life.

 

[deerefanatic]

Thanks for the warning! LOL!

I think the PID's are the way to go... Self contained, easy to program, and they give that "industrial" look.....

Just stove design now.........