Coleman Senior Member Joined: 24 Oct 2003 Posts: 26 Location: San Francisco Expertise: I live coffee
Espresso: Isomac Grinder: Solis Drip: AeroPress Roaster: Black Cat Only
Posted Sun Feb 22, 2009, 7:43pm Subject: PID on an Isomac. Wiring Question.
Cheers; I'm adding a PID to my Isomac Millennium and I'm having trouble finding a wiring diagram. I'm going to take the leads off the pressurestat and hook them to the SSR. Trouble is, what are the three leads on the pressurestat? Hot, ground and the third? been searching for a bit but I'm coming up short.. I cant find a suitable diagram for this mod..
Any help appreciated..
Thanks-
Coleman.
Within light there is darkness, But do not try to understand that darkness. Within darkness there is light, But do not look for that light. Light and darkness are a pair.
GabrielB Senior Member Joined: 27 Mar 2007 Posts: 232 Location: Chicago Expertise: I live coffee
Espresso: Maver Junior (HX), Silvia... Grinder: Wega Max (K6), Rocky Vac Pot: Bialetti Moka & Brikka Pot
Posted Tue Feb 24, 2009, 8:36am Subject: Re: PID on an Isomac. Wiring Question.
I believe the three leads are Common (hot), Normally Open (NO) and Normally Closed (NC). My machine, which is based on the Isomac models, is wired with Common and NC. So when the pressure falls below the desired setting, it "flips" from open to closed and engages the element. Then my boiler LED on the front turns on as well.
I'm guessing you may have all three wired because you have two boiler LEDs on the front (green: ready and NO position, red: boiler engaged and NC position).
*I may have the logic backwards on this... regarding NC and NO... but I believe that's why you have all three wired*
This is also a good reference: http://www.espresso-restorations.com/p-stats.html
Coleman Senior Member Joined: 24 Oct 2003 Posts: 26 Location: San Francisco Expertise: I live coffee
Espresso: Isomac Grinder: Solis Drip: AeroPress Roaster: Black Cat Only
Posted Tue Feb 24, 2009, 10:16am Subject: Re: PID on an Isomac. Wiring Question.
Ok.. I got it.. You're right.. Hot; Normally Open and Normally Closed. ---- When the reed switch goes from (NC) to Hot it heats and when it goes from Hot to (NO) the lamp lights indicating it's not heating.... (I wish I had the schematic..) A clue was on the "Espresso-Restorations" site where he said "YOU MUST COVER/INSULATE THE (NO) NORMALLY OPEN CONTACT!" I think it's a SPDT? So my solution would be: the HOT and the normally Closed are wired to the SSR .. The Lamp that illuminates when it's not heating is now the only issue on how to connect.. Ideas.?
Coleman.
Within light there is darkness, But do not try to understand that darkness. Within darkness there is light, But do not look for that light. Light and darkness are a pair.
GabrielB Senior Member Joined: 27 Mar 2007 Posts: 232 Location: Chicago Expertise: I live coffee
Espresso: Maver Junior (HX), Silvia... Grinder: Wega Max (K6), Rocky Vac Pot: Bialetti Moka & Brikka Pot
Posted Tue Feb 24, 2009, 10:30am Subject: Re: PID on an Isomac. Wiring Question.
The lamp that is on when not heating should be the green one, correct? So wire it so the green lamp goes to the NO... when the pstat switches to NO, the circuit will completed for the green LED (boiler off).
My guess is you will need a wire from the Common and one from the NO position to go to the green LED.
I think Paul Pratt from Espresso-Restorations says insulate the NO contact so someone or something doesn't make contact with that side and you blow your machine up (doh!)... like on my machine with one boiler LED. But since you have a two LED configuration, all your contacts on the pstat should be in use.
Coleman Senior Member Joined: 24 Oct 2003 Posts: 26 Location: San Francisco Expertise: I live coffee
Espresso: Isomac Grinder: Solis Drip: AeroPress Roaster: Black Cat Only
Posted Tue Feb 24, 2009, 11:01am Subject: Re: PID on an Isomac. Wiring Question.
But.. I'm taking off the Pressurestat, and adding a SSR driven off the PID. The SSR has 2 contacts.. This is the new issue.. It's basically a SPST. (2 terminals) the Pressurestat was a SPDT (three terminals) There is a way to wire another relay for this.. I dunno..
C/
Within light there is darkness, But do not try to understand that darkness. Within darkness there is light, But do not look for that light. Light and darkness are a pair.
GabrielB Senior Member Joined: 27 Mar 2007 Posts: 232 Location: Chicago Expertise: I live coffee
Espresso: Maver Junior (HX), Silvia... Grinder: Wega Max (K6), Rocky Vac Pot: Bialetti Moka & Brikka Pot
Posted Tue Feb 24, 2009, 12:20pm Subject: Re: PID on an Isomac. Wiring Question.
Ah, I see. I forgot that you were putting in a PID. I would probably just wire in the red LED to see when the PID was passing current through to the SSR (boiler on). And just leave the green LED unwired. Maybe you can use the green LED for a low water indicator for a future project.
Even when you figure out how to wire both the green and red LEDs to the PID with a 2nd NC SSR... the PID will most likely pulse at steady state, and you will see your red and green LEDS flipping back and forth. It would look like the lights on top of a police car (red, green, red, green, etc.) every second. I'd personally find it a bit annoying. :)
*I'm not a EE... so everything I said could be entirely wrong* :)
Can you post a photo and/or model of Isomac you are working with?
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