So my junior (circa 90s) with vibe pump is finally put together


I plumbed it in and have a couple of other minor issues I am hoping you folks have knowledge of....

1. The pressure gauge seems to stay at around 0.2 to 0.4 bar. I am able to dispense water from the group head despite this.

What would need adjusting in this case? From memory the gauge went all the way up to 0.8 or so prior to me taking everything apart....

I think the Pstat is OK as the temperature for hot water and steam come out very hot!



2. The boiler safety valve seems to hiss quietly and a small bit of steam comes out of the holes circled in red. It's not popping the valve, but is that normal? I'll probably end up replacing it...




thanks for reading

Never a good sign for a safety valve to leak.

What's your steam like? Your pressure gauge could be broken (0.2-0.4 is super low - you want it at 1-1.2).
Or your safety valve could be bad. Or both.

If heating elements are getting power than the pressurestat is likely fine, you can check and make sure the contacts are clean and then adjust the pressure upward. I would recommend replacing the safety first.

Besides not being particularly safe, a constantly leaking safety valve will also make it hard for the boiler to maintain pressure. Are you hearing the Pstat turn on and off(loud 'clicks')?

Hi

Just I do hear the p stat clicking on and off.


I will purchase a replacement boiler safety valve next time I head out to the espresso dealer.


here's a video of hissing + pstat clicking if it gives any more clues...

https://vid.me/nzIV

If you are sure that the steam power and water temperature from the group head are ok, maybe you are non reading the real boiler pressure on the gauge, maybe is higher so that's why the safe valve hissing.
Do you even dismantled the safety valve once refurbished the machine?

hi
i didn't dismantle the boiler safety valve as it's not advisable to do so, i believe it's factory set at 1.8bar or so for a reason

correct.
Anyway with a "real" boiler pressure of 0,2/0,4 bar, you should not to get proper steam power neither proper water temperature at the group head.

First, I agree in replacing the pressure safety valve, that is your first issue. Second issue, you either have a bad pressure gauge, or you need to adjust the setting of your P-stat. The P-stat is the control circuit for power to your heating element in the boiler via the relay. In the video you posted you can hear the valve leaking, but also the p-stat click the power on, and then click it off to the heating element. You need to tighten the small screw on your P-stat. As you tighten, the pressure required to close the control circuit to your heating element will go up. As you losen it goes down. From the sound of your video, the dead band seems (based on time the boiler is turned on before it goes off) about the same as mine was on the Cimbali machines I rebuilt, but my ear is not a very good calibration tool. I think you will see the pressure go up as you tighten the screw. Of course, you could also have a bad pressure gauge and it is really at 1.1 bar on the boiler and reading on the gauge incorrectly. This is why I would change the safety valve first. At any pressure in the boiler above atmospheric, the water in your boiler is superheated (over 212 degrees), you will still get steam even at .4 bar, and the water coming out of the water dispenser will be very close to boiling. Where you will have trouble is actuall pulling a shot of espresso. After you do a cooling flash (should be a short cooling flush at that pressure), the temperature of your shot will taper off of 198 deg fairly quickly. The pressure of the shot that you are extracting will still be at 9 bar assuming your pump pressure is set correctly, but your temperature profile of the shot will not be good. The other area you will be challenges is getting the milk churning when you are frothing, you will have trouble getting a nice silky texture. On my Cimbali bistro, good texture milk is more difficult for me at .9 bar in the boiler than 1.1 bar, so I imagine extremely difficult at .4 bar. If you really want to dig in deeper, it is not very expensive to buy a few gauges to verify boiler pressure, brew pressure, brew temperature just above the screen so you can get into understanding the pressure and temperature profiles of your machine.
I hope this helps some.