Adding SSR to ECM Giotto

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ArchieCoffee
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#1: Post by ArchieCoffee »

Hi all,
I have an ECM Giotto from 2000. I recently had to get a new heating element, and the 1200W variety that it came with is no longer available, so I had upgrade to a slightly higher powered 1400W element. Because of this, I purchased a 25A SSR from Espressocare.com (Stefano is the BEST), and I got a heatsink from Auber.

The machine is a very basic E61 from that era. It has a Mater pstat (not the Sarai with the built in relay), and heating element is connected to one lead from the pstat and the blue wire from the power switch.

My question is in how to wire up the ssr. Do I basically insert it into the middle of this chain? Meaning, do I connect the blue wire from the power switch to the + control terminal and the pstat wire to the - control side terminal (A1+ and A2-), and then just connect the + and - on the load side (it's labeled as L1 and T1) to the heating element?

I've uploaded a schematic for the ECM Giotto, as well as one for the relay.

Could anyone give me any advice on how to rig this up?


JRising
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#2: Post by JRising »

I take it you already see that that Giotto diagram is not your wiring diagram (Yours is older with the P-Stat directly switching the Element).

The fewer connections on the way to the main load, the fewer places there are to heat up so let's do it this way...


The black wire that currently runs to P-Stat from Gicar, Run it first to the SSR Load, then another from the same terminal to the Common on the P-Stat. A new wire from NC on the P-Stat to the Control Input - on the SSR. The other load terminal then connects to the Element. and blue neutral jumper needs to be made and connected from all the multiple blues to the other control terminal on the SSR.

jpboyt
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#3: Post by jpboyt »

You have the wrong SSR for your application. You need the AC control voltage version not the 24VDC shown in the picture. The last schematic also needs to be revised so that the heating element current does not run through the control box. You want the relay voltage in the control box to pass through the pressurestat, the over temp, and then the SSR trigger terminals so that the control box relay is only handling SSR trigger current. The removing of the heating element current from the control box is the main reason for adding the SSR. This moves the current path without losing the reservoir no water heat inhibit safety function. SSR failure in conductive state would be handled by over temp switch.
jpboyt

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homeburrero
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#4: Post by homeburrero »

I agree with jpboyt, maybe with one exception:
jpboyt wrote:You want the relay voltage in the control box to pass through the pressurestat, the over temp, and then the SSR trigger terminals so that the control box relay is only handling SSR trigger current.
I think it may be better to wire the hi-limit (aka safety thermoswitch) on the line wire that feeds the element rather than the control wire. If it pops open it will always interrupt the current irrespective of all else. My thinking is that If you put it on the control side and the SSR manages to fail closed, then even if it heats and trips you'd still have current to the element. Hope you (jpboyt) agree.

jpboyt wrote:You need the AC control voltage version not the 24VDC shown in the picture.
Agreed, but I think this is also a case of a wrong diagram. If he picked up a RM1A23A25 from Stefano he does have the AC control version of this SSR.

P.S.
The discussions here may be informative: ECM Giotto steam pressure goes up without stopping


And finally, should add a safety warning.
Rewiring an espresso machine can lead to dangerous situations that can damage machine components, or worse yet injure or kill someone. If you lack electrical expertise then enlist some expert help to review and test your rewiring.
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

ArchieCoffee (original poster)
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#5: Post by ArchieCoffee (original poster) »

JRising wrote:I take it you already see that that Giotto diagram is not your wiring diagram (Yours is older with the P-Stat directly switching the Element).

The fewer connections on the way to the main load, the fewer places there are to heat up so let's do it this way...
image

The black wire that currently runs to P-Stat from Gicar, Run it first to the SSR Load, then another from the same terminal to the Common on the P-Stat. A new wire from NC on the P-Stat to the Control Input - on the SSR. The other load terminal then connects to the Element. and blue neutral jumper needs to be made and connected from all the multiple blues to the other control terminal on the SSR.
First of all- you're totally right. Like a dummy, I grabbed the wrong diagram off the ol' interwebs. My ECM is so old that it doesn't actually have a high limit switch. And yes, the ssr that homeburrero linked to is the one that I got, with the addition of a heatsink. I think your diagram should work perfectly. Thank you so much.

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Jeff
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#6: Post by Jeff »

Just be careful with both existing and new wiring with respect to hot and neutral. For some reason, some European machines get them reversed in their 120-V units. They'll function, but having everything "live" and switching neutral isn't the safest thing.

JRising
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#7: Post by JRising replying to Jeff »

Agreed. If you do see that they're reversed, it is a very simple fix to correct it at the main switch. Once it's done the machine is much safer to anyone who ever looks around in it.

jpboyt
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#8: Post by jpboyt »

Over temp in the heating element circuit is the better way to prevent the SSR failure in conductive state from causing a boiler to continue to be heated after an over temp. Good catch.
jpboyt

jpboyt
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#9: Post by jpboyt »

To Archie Coffee. I think you missed the point of the last few posts. The schematic is incorrect. It has the element current passing through the relay in the control box. This condition is to be avoided as it removes the advantage of using a SSR in the heating element circuit.
jpboyt

ArchieCoffee (original poster)
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#10: Post by ArchieCoffee (original poster) replying to jpboyt »

You're absolutely right. I did misunderstand that. So if my machine doesn't have a hi-limit switch, where should the lead that was supposed to go there go?

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