Hey guys,

I am in dire need of help. I am at a loss at this point, so here goes.

Problem:

Low boiler pressure - I can achieve a maximum of .7bar and the heating element shuts off. It will come back one when the pressure lowers to about .4 bar.

I replaced the Sirai pressurestat as that was the recommended solution for low boiler pressure if adjustments did not respond. The new pressurestat made no difference. It appears that the boiler is not reaching a high enough pressure to trip the mechanical solenoid in the Sirai pressurestat. Is there something else that could be controlling the heating element? The thermofuse is not tripped. The machine cycles the heating element like normal, but there is low steam and brew pressure.

Any thoughts?

Also, I just finished a full overrhaul on the machine. I took everything apart and cleaned the components in citric acid. I added and OPV and anti-vac valve and replaced the vibratory pump. All functions beside boiler pressure function as normal.

Please help. I don't have the funds to keep replacing parts left an right.

if the boiler element cycles on and off , the pstat is working

adj pstat

could take a full revolution of the sirai adjustment screw to increase boiler pressure by .1 bar
so try a big swing at it , it a heavy spring

Correct me if I am wrong. The Sirai pressurestat, when working properly will click every time is cycles open and closed?

The pressurestat is not clicking when the heating element cycles off. I have tried 8 revolutions of adjustment with no change in pressure. I cycle the steam wand 3-4 times for 30 seconds in between adjustment. I am suspecting that there has to be something else I am missing. My thought is that the element is shutting off before the pressurestat reaches its adjustment point (because the heating element light goes out, but the pressurestat hasn't clicked yet). The pressurestat is 1 day old. I am experiencing exactly the same functionality as I was with my old sirai pressurestat after the rebuild.

Could the cigar box cause the heating element to cycle?

Could the autofill probe affect anything?

I am afraid to replace the autofill circuit at $150 if I have no way of testing it first. The boiler appears to autofill a little after about 3-4 thirty second blasts of steam.

As far as I know, heating elements either work, or they don't. I tested the element right after the rebuild and it was between 10-11ohms which is right where I understand it should be for a 115v, 1200w element.

I can hear my Sirai pstat click on and off, but each machine has different acoustics. If you hear it switch on, then it's likely the pstat. Likely...

The "autofill circuit" as labeled does cost $150, but that is the Gicar controller and the whole brains of the system. If you want to test the fill probe you can test that with the machine top off, power on, remove the wire that goes to the boiler level sensor probe and you should immediately hear the pump kick in - reconnect the probe wire as the test is completed.

The pump running to fill the boiler after a few steaming sessions is quite normal, so that sounds like your auto-fill is working fine.

Back to the Gicar controller... When I purchased my machine that part was faulty. It would have different actions depending on the heat of the machine. When I first turned on the machine it would heat even though a water out warning light came on, and once warmed up the sensor light would work correctly and the pump would also work. Eventually when it died it didn't fill the boiler and burned out my heating element on it's way out.
I would seriously look into that controller. There's a member named JPBoyt that rebuilds these controllers for about 1/2 of what they cost new. Or you can just pick up a new controller from EspressoParts like I did for about $150.

Do the following only if you have electrical skills, are careful, and know what you are doing...
(I'd remove the outside shroud for ease of access.)
You could wire up the system to bypass the pstat temporarily.
Put a pressure gauge on the steam wand.
Turn on the machine and watch the pressure as things heat up and see if the heater does turn off.
If it turns off then you can check the voltage to the heating element to see if any AC voltage is there.
If there is no AC power to the heating element I would suspect the controller at that point.
Listen for any noises at the controller when the element switches on and off.

IF you are going to remove the controller for any reason please make sure you label all the wires first. Permanent marker on the connection covers works okay for that.

Thank you. I will test the controller this was any see what happens. I appreciate your help.

Final note. If you are testing without the pstat in place make sure you don't run the boiler at high pressure. I would recommend 1.5 BAR be your maximum pressure, and you should try to keep it under 1.3 BAR.

Best of luck!

If it makes it to 1.0 bar without the pressurestat, I will know there was a change. I haven't been able to get it about .7-.8. Thanks for the advice. I am definitely going to play it safe.

my bad
you are correct the pstat should cycle with the boiler element
this is a new controller error for me

1 SSIC , white , probe safety , shuts off element or everything
2 SLIV , red , probe level , min or max water level
3 SRIF , 2 yellow/green , probe reference , ground
1-3 , low voltage , 4-10 , higher voltage
4 EVEROG , gray, 3 way
5 RES , black, element
6 EVCAR , red , auto fill
7 POMPA , orange , pump
8 COMUNE , 2 blue , AC neutral
9 LAMP , white , ? low water , element , power?
10 AC , 2 red , main power

Thank you all so much for your help. I found the problem. Luckily, the autofill unit was not the problem. It was the safety thermostat. It seems that it is finicky and needs replacing. To test, I disconnected the wires from the thermostat and place a 30amp blade fuse between the wires. I fired it up and the machines comes to pressure and functions flawlessly. I will order a new part asap. In the meantime, I think it will be ok with the blade fuse in place.

When installing the new safety thermostat, is there a very specific thermal paste I need to use between it and the boiler? I have a tube of thermal paste used for computer heat sink components. Is that ok?

I seriously can't thank you all enough for the support and information. I though I would end up replacing every part on the machine before finding the problem.

Now to brew some espresso.

I had one of those thermosensor auto-reset fuses on my La Pavoni that gave me trouble. I replaced the old pstat before realizing that wasn't the issue too. Still haven't replaced the thermosensor on that machine yet, but I will next time I order something from Stefano.

Enjoy that Oscar. Mine served me well for a year now. It's getting retired since the Strega came in, but I still like the old Oscar. Maybe I can get my sister to take it - she needs an espresso hobby!