Relay issues with trying to PID La Pavoni Europiccola

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eric_pavoni

#1: Post by eric_pavoni » Sep 13, 2019, 4:16 pm

Hello! Has anyone PID'ed their machine before? I have been running into a lot of trouble trying to do a pid on my pavoni pre mil with pressurestat (the switch is the red switch on top + green light on the bottom); Everything else is running smoothly (temperature monitoring, pressure monitoring, etc), but I am having a hard time figuring out where to insert the relay such that the pressurestat will still override the circuit on max pressure. I've gone through 3 solid state relays, 40A rated 40A rated and finally 100A rated one, all of which seemingly ended up getting stuck permanently on closed loop. (But I am sure the PID is working because the LED on the solid state relay toggles in accordance to the duty cycle that I am shown as temp/pressure increases.) . I've attached a wiring diagram of my machine. Any help is appreciated.

I feel like I've tried to connect the ssr across the right wires... However it always seems like the ssr fails on me. I seriously doubt theres that many faulty ssrs floating around amazon but at the same time I can't figure out where my wiring goes wrong. All normal functionality seems to be working despite the relay always being closed. The relay is currently in series connection with the installed pressurestat.

http://partsguru.com/user/LAPAVONI%20WI ... ICCOLA.JPG

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Jake_G
Team HB

#2: Post by Jake_G » Sep 13, 2019, 8:16 pm

These results fom the search query "PID Pavoni" might be helpful:

La Pavoni PID control mod walkthrough

La Pavoni + PID = better temperature control?

Based on your schematic, I would place the SSR in the location crudely scribbled in red:
Image
In this location, the pressurestat functions like factory if the SSR sticks closed.

Cheers!

- Jake

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homeburrero
Team HB

#3: Post by homeburrero » Sep 14, 2019, 12:46 am

Jake_G wrote:Based on your schematic, I would place the SSR in the location crudely scribbled in red:
That would work, but I think I'd wire it like this so that the green light works like the factory version (lit whenever the heater element is energized):

Image

With respect to the failing SSR, perhaps it needs a cooler location or better heat sink? Going with that high amperage SSR should help, but not as much as you might think (per SSR Heatsink Basics )
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

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Jake_G
Team HB

#4: Post by Jake_G » Sep 14, 2019, 12:50 am

homeburrero wrote:That would work, but I think I'd wire it like this so that the green light works like the factory version (lit whenever the heater element is energized):
Good call.

I would do the same.

Cheers!

- Jake