I hope my electrically challenged brain can get this , but I thankyou for educating me .
- To my knowledge that same relay was used to great success int he past , I cant imagine that it was only used on semi auto machines , so I am not sure it had adverse effect on the control box .
- The way I understand it worked , with the relay in line , is that the the brew switch ( semi auto or auto ) activated the solenoid only for few seconds allowing only water mains pressure to enter , THEN the relay allows the pump to kick in .. for full 8-9 bar pressure ... then all is off .... ALSO again as I understand , the pump didnt come on when the boiler fill solenoid was called for filling ... lowering the noise of the pump kicking in every time more water is needed to fill the boiler .
- When you say , " power the relay switch from and independent LIVE wire " to me that means a live wire not shared by the control box ... I am not sure my machine has that , I know it has a brew switch AND a automatic dosing switch ... working as either or .. but I am not sure the brew switch has an independent live wire that is not shared with the control box ( I Guess I have to trace the wires and colors and check physically on the machine ...) BUT I know that the original pump had only two wires coming into it ( Hot + / Neutral ) I just need to double check to see if that + wire is the same that goes to control box AND brew switch ..

The experts here can correct this as necessary (and please do), but I think this is what you have in mind. The switched hot lead from the espresso machines main power switch (or, if you use an external power switch, that hot lead FROM that switch) connected to B1. When power from the control box is sent to B2 it closes the circuit between terminals B1 and C. That way, the control box's internal relay only sends enough current to close the relay's contacts, and the full load for the pump is carried by the added SSR's contacts.

Note: If you make fun of my use of the term "Contacts" for a solid state relay, I will make fun of your use of "Positive" for AC current!

Good job on the picture, and looks like the ideal wiring solution to me. (And I think it's a mechanical coil relay with a solid state timer, so you'd be correct in calling them contacts.)

Randy G. wrote:<image>

The experts here can correct this as necessary (and please do), but I think this is what you have in mind. The switched hot lead from the espresso machines main power switch (or, if you use an external power switch, that hot lead FROM that switch) connected to B1. When power from the control box is sent to B2 it closes the circuit between terminals B1 and C. That way, the control box's internal relay only sends enough current to close the relay's contacts, and the full load for the pump is carried by the added SSR's contacts.

Note: If you make fun of my use of the term "Contacts" for a solid state relay, I will make fun of your use of "Positive" for AC current!

Randy , first thank you .. , second .. rest assured I am the last guy who should or will make fun of any electrical terminology !! IT looks like your diagram makes a lot of sense ... I do however need to do some wire tracing on my actual machine . Reason is on the downloaded manual , shows two different " Junior model " electrical diagrams , one with six wires into the six pole connector on the control box ( with what seems like two Neutral terminals ) and the other one shows only five .. with one Neutral only ... .. not sure if it makes a huge difference in our diagram .. if memory serves correct I do recall mine has six wires .. just to have to double check what is the exact difference ...I do feel I understand your diagram though enough for me to give it a shot . Thank you again , Max

Max,

1 - The only wire that you need to be specific about is the one that is already going to the pump (the "Hot" wire from the control box to the pump). Disconnect it from the pump and connect it to B2.

2 - Now make a wire that will go from "C" on the relay and connect it to the terminal vacated on the pump by the removal of the Hot wire in the previous step.

3 - The switched positive wire from the main power switch: It the switch has spade terminals, you can get a spade terminal piggyback adapter (basically one female to two male spade terminals). In any case, a switched hot wire of an appropriate gauge attaches to B1.

4 - The neutral wire can be connected to any neutral wire in the machine. If the relay is being placed near the pump you can just piggyback it on the terminal on the pump.

Be aware that you are getting advice from an art major. Double check all wiring before powering up.

EDIT ADDENDUM: I should mention that the tips I give above were aimed at making the addition of the relay easily reversible in that no wires have to be cut to accomplish it (depending on the machine and how the existing wires are connected).

Randy .... youre an art Major / and I am an Architect .. What better backgrounds for Espresso technical explorations ? LOL .... I thank you for taking the time to contribute I will do my best to take my time hopefully I wont fry anything but it seems straight forward .
- I am preparing the machine now .. for outboarding the pump and motor I have the new motor and pump , also
will mark and prepare the wires for the relay .
- Have to get some plumbing parts , since the old motor was a water cooled one , so some modifications are in order for the new motor
- Waiting for the relay to arrive any day
- I really want to have a thermocouple on the group head ..with a simple temperature readout , but still working out the exact parts I need .. but I guess I can do that later after everything is up and running .

Thank you again and best regards,
Max

maxwerks wrote:Randy .... youre an art Major

I WAS an art major. I graduated in 1973. So long ago we had to create our own fonts for custom projects! I was an elementary school teacher for a couple of decades. Am now a graphic artist/writer/photographer now, working as the customer service department for a major home coffee roaster manufacturer. You just never know where the road leads. To keep my art chops fresh, for fun I just finished creating this poster:


Had it printed at 20"x30" and it's framed on the wall.
(that's our new puppy)

working the layout , a thought came to mind .. would there be any function or performance difference if the relay was to be installed int the machine or closer to the remoted pump motor ?

maxwerks wrote:would there be any function or performance difference if the relay was to be installed int the machine or closer to the remoted pump motor ?

If your remote pump is easy to get to it might be more convenient (to tweak pre-infusion time) if you locate the relay out there. You do want the relay away from hot areas - spec indicates an operating temp of 70C or less - so either needs a cool location inside (certainly not near or above the boiler) or outside with your pump. I can't think of a functional or performance downside to putting it out with the pump.

maxwerks wrote:working the layout , a thought came to mind .. would there be any function or performance difference if the relay was to be installed int the machine or closer to the remoted pump motor ?

I put a delay on make relay into my machine fairly recently. The pump on mine is internal to the machine. I have thought about outboarding it at some time but have never got round to it. I wired the relay so it is outside the machine to make for easier fiddling. It should not make any difference where you locate it, but as already suggested, generally better kept cooler rather than hot.

It was very easy on my machine, as the motor is already electrically detachable from the machine by pulling apart a 3 wire female to male connector (switched live/neutral/ground). I got some of the exact same connectors and then wired it up using those connectors to fit the new wiring and relay between those original ones. There is a new male connector now going out to the relay, and a new female connector now going back from the relay. It means it can all be easily removed just by taking out the new connectors and pushing the female and male original to the machine back together.

It does mean, as has been pointed out earlier, that the full current required for the pump still goes through the relay in the control box. But, if you think it through, the actual switching on of the pump, which is when relays get some of the wear and tear, is now done in the external delay on make relay rather than the one internal to the machine. The onboard relay only switches on the delay on make relay. The switch off is still the job of the onboard relay of course, but I think there is still some advantage to the new wiring in terms of overall lower loading on the internal relay.

It now gives one further set of pre-infusion parameters to play with. I'd like to think that's a good thing, although it could create endless tinkering.