La Marzocco Linea 2AV overhaul project - Page 4

#31: Post by **AssafL** » May 4th, 2016, 6:11 am

Reading the manual for the Linea's - the idea behind the two mode switch is that:
0 - Power OFF
1. Power to all the circuitry - with the exception that the power IS NOT AVAILABLE to the boiler heater
2. Power to all the circuitry, including power to heater

You would use setting 1 to ensure all the boilers are full prior to moving the switch to mode 2 (eliminating any risk that a boiler heater will overheat and burn itself out).

If you look at the diagram you'll see that the left section of the mains switch powers the two main boilers heating elements (except the cup heater).

HTH.

NB - Given what you wrote is accurate, and given that you will INDEED TEST what I guess, It seems to me 0 1 & 2 correlate nicely with the modes above, so R & S will go to phase and neutral; R1 and S1 will be electronics (wires B & R) and R2 and S2 will go to the heaters (the two W lines on the left).

NB2 - I may be wrong. If I am wrong, you may pop a fuse, or destroy something. So be very careful, and use a DMM to verify every section you hook up.

May 4th, 2016, 8:28 am

Hey, thanks for the reply.

What I don't understand is that on switch position "1", I get continuity between S and S2 (heating element terminal). But not S1 (R wire). Wouldn't I be getting power to the heating elements then?

#33: Post by **AssafL** » May 4th, 2016, 3:04 pm

I don't understand your post. You said S and S2 but not S2?

Here is a way to draw a switch - use a truth table. X means connection:


        0       1        2    - switch position pole S
S       X       X        X
S1                       X
S2              X        X


         0       1       2  - switch position pole R
R        X       X       X
R1               X       X 
R2               X       X

Please correct and maybe I can follow what you wrote.

May 4th, 2016, 3:38 pm

Ah, sorry I ment to say that at position 1, R connects with R1 and R2 and also S with S2. I found that odd. While S1 stays discinnected. Shouldn't S1 be connected rather then S2 at position 1 when we don't want power to the heating elements?

May 4th, 2016, 3:46 pm

So is the following truth table correct? Measure it as many times as you need to validate. S & R are two completely separate poles (separate switches); X marks terminals that are shorted. (I used the code tool as it is monotype and thus can be coerced to look like a table).


        0       1        2    - switch position pole S
S       X       X        X
S1                       X
S2              X        X


         0       1       2  - switch position pole R
R        X       X       X
R1               X       X 
R2               X       X

Given that the above is accurate, and given that you will INDEED TEST what I guess, It seems to me switch positions 0 1 & 2 correlate nicely with the user manual modes:
0. Power OFF
1. Power to all the circuitry - with the exception that the power IS NOT AVAILABLE to the boiler heater
2. Power to all the circuitry, including power to heater

So the wiring will be:
1. S & R will go to phase and neutral (respectively);
2. R2 and S2 will be electronics (wires B & R);
3. R1 and S1 will go to the heaters (the two W lines on the left).

HTH - and be careful.

May 4th, 2016, 3:51 pm

Yes, that table is correct.

It may be possible that I didn't replace the cam in the right orientaion after having it out. Should I try to adjust the cam?

Yes, code tool is easier to follow, thanks.

Edit: Rather then trying to set the cam a different way, I will wire it up like you mentioned and see how it goes.

Thanks very much for your generous help!

#37: Post by **AssafL** » May 4th, 2016, 4:20 pm

trumz wrote:Yes, that table is correct.

It may be possible that I didn't replace the cam in the right orientaion after having it out. Can't find a diagram to verify, but it seems to me that I need to adjust the cam.

Also tried the Bremas site - the CA 032 (32A) series is clear. The wiring of the GZ22V part number isn't in any of the catalogues. Yet another Italian bit of obfuscation to make life difficult. Luckily - it seems to be a standard part. I don't know what the V stands for - but a GZ22 switch is called a "Multi-step cumulative change-over switches with "0" position". Carlo Gavazzi also makes them (but the Gavazzi stuff is expensive). Here is the truth table from the Gavazzi catalog. (ignore the contact marking - it is a manufacturer specific marking scheme).

In essence, the Carlo Gavazzi Truth table would have been as follows:


        0       1        2    - switch position pole S
S       X       X        X
S1              X         X
S2                        X


         0       1       2  - switch position pole R
R        X       X       X
R1               X       X 
R2                       X

Is there a way to fit the cam so it works like the above? Theoretically it shouldn't matter - but in reality the cam should be positioned properly or the entire operation may be compromised (e.g. make before break or break before make, sliding over surfaces they shouldn't etc.).

I'd also consider asking LM. They are very friendly.

http://users.rcn.com/erics/ · #38: Post by **erics** » May 4th, 2016, 6:40 pm

I'd also consider asking LM. They are very friendly.

I would also. Certainly LM should be able to furnish you with a schematic of that specific Bremas switch.

I spoke to Bremas USA and they would not release any diagrams of that particular switch (company policy). Apparently the switch is "custom".

If it were me, I would apply, say, 12vdc to the power input terminals of the switch. With the switch in the "0" position, there should be zilch voltage on all of the other terminals. At position 1, there should be power to all terminals other than the heating element circuitries of both boilers. At position 2, all terminals should be live.

If you think you installed the cam mechanism incorrectly, all bets are off and you would then be better off by simply purchasing a new switch.

#39: Post by **AssafL** » May 5th, 2016, 2:37 am

Did you see this?

http://lamarzoccousa.com/docs/tb/TB18-f ... Wiring.pdf

May 5th, 2016, 5:41 am

Yes, I saw that tech bulletin, thanks.

I adjusted the cam on the S side back to normal operation. It easy enough to adjust the cam. You take the shaft off of the R side and only turn the S side cam until it's correct. Took me 10 minutes and lots of double checking.
So now I have proper operation of the switch.


        0       1        2    - switch position pole S
S       X       X        X
S1              X         X
S2                        X


         0       1       2  - switch position pole R
R        X       X       X
R1               X       X 
R2                       X

Thanks for you help, appreciated.