Even before I would consider replacing a relay(s), I would want to be VERY CONFIDENT that the machine's components which control these relays is sound.

How about posting some internal pics of your Giotto?

Thanks for the quick reply Eric-

The whole machine is shut down.. no pump, no heat- just RL3 opening/closing every two seconds or so...

Not sure what you're looking for but I attached a few pics below...
LMK if there is something you want to see closer up....
Other than replacing the safety valve, vacuum valve and pstat (replaced with Jager),
The only mod on this machine is the conversion from the original tank that had the supply and return tubes hanging into it, to the drop in tank with the plastic coupling.
Everything else is original...


Tried tilting the machine towards the probe but didn't do anything - now wondering, if the level probe is open (I'm guessing that would signal empty by floating the voltage), wouldn't that trigger the pump to fill the boiler? And if it's signaling that it's not empty/low (i'm guessing it would close to ground when it contacts the water), wouldn't that allow the heater to run?

The heater resistance is 8 Ohms-
- I've always used water filtered with active carbon- no scale problems....
the machine was completely descaled a few months ago (although didn't really need it).. at the time, I pulled the heater back then and checked the tank with a flash light... clean as a whistle....


I could really use a run down of what voltages I should expect to see on each of the pins of the Gicar on a cold machine...


The loose green/yellow wire along the back is the chassis ground from the original tank set up....



Back



Pump Side


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controller side

The loose green/yellow wire . . .

Make sure this green/yellow wire is connected to a good ground. The small auxiliary tank which has connections for pump suction, OPV return, and deaerator valve output has a white wire attached. This white wire is SIMILAR in function to the wire going to the water level probe inside the boiler. Continuinty between this white wire and ground keeps the machine "on" when it is supposed to be on. Likewise, disconnecting this white wire should shut the machine down.

So, you might try establishing a good ground between the white and ground and let's go from there.

Thanks-

I know that (but you're right) .. that's where I originally started yesterday ... the first test I did before suspecting the Gicar was to connect the white wire from the auxiliary tank to the green/yellow wire (and I just tried it again) ... the loose green/yellow wire is bolted to the chassis on the other end- using the common ground screw on the chassis floor below the pressure gauge. It was originally the ground connection for the old water level sensor - serves no purpose now- it could and arguably should be removed...

The circuit is basically the same with the new aux tank - the brass pin in the center runs right through the and is bolted to the chassis- it is ground... so the green/yellow wire is no longer necessary . As long as there is enough water in the aux tank to cover the screw that holds the white wire in place, the white wire has a connection to ground...

Yes, I hear you when you say the pin is bolted to the chassis and that should be good. As long as there is continuity between the brass pin and the main ground lug you circled in red, you're OK there.

Then the ground wire from the Gicar should also have 100% continuity to ground and the white wire should have continuinty when disconnected from everything. Now reconnect the white wire to the Gicar and intentionally ground the other end - or did you do that already?

yep...did that already.
- also while I was waiting to hear back, swapped the pstat out and back with the original, just to make sure it wasn't misbehaving in some way....

I think that leaves us with the pump and the solenoid
fwiw - the pump operates if I jumper the relay on RL3...

Unfortunately, that's the end of the road.

It appears as though RL3 is activated when the machine is turned on AND it receives the "OK" signal from the baby reservoir. So, if you can cause RL3 to be closed, the machine should operate normally - yes or no?

I can jumper RL3 closed and the pump kicks in... it will run as long as it's jumpered.. as you mentioned RL3 turns on the solenoid, the pump and I think the heater too... don't think we want them all running continuously do we?

Absolutely not - I was mistaken about RL3. From your description, it is the relay that operates based upon a "signal" from the boiler level probe. That being said, make sure the boiler is well grounded.

RL1 (and only RL1) should turn on the heater - that is the 16A relay - right? On the Gicar box, F3 is labeled "RES. RL1".

I can only assume then, that RL2 is the relay that operates based upon a valid "signal" from the baby reservoir. So with the reservoir full with reasonably conductive water (or the white lead at the baby reservoir grounded), RL2 should close when the machine is turned on.

Hey Jim,

Wanted to jump in with a couple of notes. Even if you don't suspect it, I'd recommend going ahead and cleaning the water reservoir probe and contacts--if they have reduced conductivity it can muddle your troubleshooting. Also, your black box is definitely of a different spec than mine, but FWIW your 16A relay switches the boiler heater, the 10A relay is for the pump, and the last one, ~3A I'd guess, is for the solenoid.

As far as what voltages to expect, my tool of choice ended up being an induction-type AC current detector, since, in my situation, I either had current to the boiler heater or nothing, and the current probe gave me a quick view as to what was on or off without having to pull wires and route in a VOM. For my set-up though, on the "big wire" side of the control box (AC input, boiler heater, pump, etc) , I was getting about 95% of the mains voltage, so close to 110VAC, on the "little wire" side typical values to the water reservoir sensor, and boiler water sensor were ~ 1.6VAC.

In the end, I replaced my 16A relay, and all is well.

Pardon me if you've already addressed this in your thread with Eric, but when you disconnect the boiler water sensor wire and switch the machine on, does the pump run?

Cheers!