Just a couple of notes on this topic:
If you have an "automatic" machine with a flow meter, there is (at least on LM's) an error in the software when the CPU does not receive input from the flowmeter. I can't remember off hand what the delay time is but you should test before doing all of the work.

All of the connect/disconnect switching on 220/240 is accomplished on one leg of the power (single phase only). This is standard in the industry for the most part including your 220V dryer (there are a few exceptions however) and most 220V appliances and tools. There is no real difference between switching one leg or both. The goal is to stop current flow. Yes, one leg still has potential but so does the other right before the switch. The pump is an unusual case on the LM because it is external and still has one leg with a potential of 120V. So if the wires were disconnected you could get a shock from that to ground.

BillC

I had PM'ed Bill with my scenario and this post was his reply. I asked him whether I could fool the computer into thinking the flowmeter was registering flow and am awaiting his reply. If he doesn't post it here, and he doesn't mind, I will post his reply.

Since I never use the auto feature, I may remove the computer anyway but for now, I would rather leave it in.

Billc wrote:Just a couple of notes on this topic:
If you have an "automatic" machine with a flow meter, there is (at least on LM's) an error in the software when the CPU does not receive input from the flowmeter. I can't remember off hand what the delay time is but you should test before doing all of the work.

I just ran into the same scenario, as I was looking for a way around the flowmeters, using the EE Solenoid to banjo tube, and spoke with jpboyt where he tested it, and it was a 5 second delay and the LED's start blinking on the Keypads. Though this is the only thing the error does.

Yes, but I think that it does not stop when the programmed volume is reached......?

Correct, but I think Mitch said he doesn't use the AV function anyway, so my guess is he is timing his shots and using the manual switch, so no need to auto-stop.

This is correct. I never use the AV section.

I'm still waiting for one part to begin my project, I guess I will find out soon enough!!

Keep us informed on your progress. I'm slowly finishing up my 2AV, always looking for more upgrades.

I finally have all the parts and a free day so I decided to tackle the job of wiring the timer. There are six wires to connect and so I tested the easily available wiring points on the LM and found what I think is the easiest connections. If you look at the wiring diagram there is a four connection block located on the top behind the brain box. I tested these and found the forward two to be always on and the back pair to be on when the brew switch is activated so I used these as my constant power and sensing power. On the left side (by the main power switch) is another connection block where power to the water pump is located. I used the Black pump wire to connect my output.

First problem is when I turn on the machine, the three way valve opens and allows water to flow out of the brewhead.

Does anyone have a suggestion?

(I know this is a rambling post but I'm in the middle of it and am trying to solve it myself)

Thanks!

I've played with this for the past two hours and I think I'm going to have to abort it for now. If there was only one circuit involved when activating the pump, it would be simple but there are at least three different activation points; the brew switch, the automatic panel and the steam boiler filler.

I still believe this on timer would work, it is just more complicated than I anticipated and a much more involved scheme is required. I'm not an electrical engineer and therefore will defer to others more qualified to experiment.

Oh, and one more complication is when cleaning and backflushing, you wouldn't want the pre-infusion function to be active. I think for now, I will be happy with my machine!

Looks like I can't give this up just yet. I've been thinking about what went wrong all weekend and I came up with some ideas. When I connected the timer, I used the connection block that had the two circuits for the 3-way valve and pump activation. That was a mistake. I think a better connection point for the timer would be the main power block. From there I can connect the "always on" circuit to the main power. I can break the pump circuit there too. The only circuit I can't seem to conceptualize is the sensing circuit.

My question:
If the "always on" circuit connects to the timer on pins 2 and 7, and the sensing circuit connects to 2 and 6, wouldn't the sensing circuit get energized by the common pin 2? I think that's what caused the 3-way valve to activate on my previous installation.