Hi all. This week I was surprised to find that the low water shutoff for my VBM Domobar Super has stopped functioning. Luckily, I discovered after making a couple of shots - when I started cleaning the screen, very little water was coming out. I checked the reservoir and it was nearly empty, but the shutoff had not kicked in. I can even lift the reservoir (and the metal plate it rests on lifts up normally) and the shutoff will not engage.

Going to pull off the shell tonight and investigate - any tips on what to look for / what might cause this?

That can be a problematic failure because it can lead to boiler overheating. The power for the entire machine goes through the contacts of that switch. Theoretically, you can extend its life by keeping the reservoir full enough to avoid its activating the switch which could cause arcing on the contacts, particularly if the heating element is engaged when the contacts open.

The switch is an easy replacement, and easy to test with a ohm meter. When you get the case off be sure that the switch is being moved far enough to activate it. Then pull the wires and check it with an ohm meter... Unplug the machine first, of course.

Unfortunately, the switch runs close to $40 shipped... ouch. I have thought about using the switch to activate an SSR so that the switch does not have to handle the full current current load of the machine.

Just check that the intake hose was not rounded down through the water and then upwards over the level of the water. There were a few machines that had longer than usual hoses. Also check to make sure the intake hose is not pinched between the body and water tank platform.

Another area is the adjustment of the platform under the reservoir, but I have not seen this scenario on the Vibiemmes as I have seen on the much older Isomacs (current stock corrected)

Just to note...When a switch fails, it will not send power to the heating element. We have never seen it fail in the reverse - where it sends power to the heating element when the water tank comes up. The beauty of this scenario is that when a switch fails, no further damage can be done to the machine.

Here is an electrical schematic of the Vibiemme Hx machine created with the assistance of Randy G. and Ian E.

When the water reservoir switch opens, power is cut to the entire machine. A "full size" copy of this drawing is available on my crude FTP site: http://users.rcn.com/erics/ . It is a very reliable switch as I do not recall ever seeing a post concerning a problem with same.

I can lift the reservoir completely off the platform and the shut off does not click over. Is it possible for something in the weight-sensor to get jammed?

Try to remove the platform that the reservior sits on on. It will lift out. This could be something as simple as that platform being jammed or something under it preventing the weight from triggering the switch.

Barry B

The switch is hold in position from 2 adjustable bolt and nuts,
they are mounted in 2 grooves (sliding up and down will make the weight adjustment)
the bottom of the reservoir plate also has a bolt mounted on that goes to touch the flange of the micro,


A. make sure the flange is been touched by it

B. check to make sure that the switch didn't slide down; perhaps the nuts came loose

see picture

Loose mounting nuts on the switch are my guess. It could have vibrated loose and slowly unscrewed over time with the vibe pump, or the pressure plate is just hung up. It uses 4 small springs on legs, if the plate got wiggled while you were moving the water tank around, it could have gotten bound up inside the case.

Thanks, folks (especially for the picture!!). I'll let you know how it goes.

Took off the cover, looked around, and couldn't find anything. The switch seems to be screwed in, but even if it's completely out of contact it doesn't shut off the heating element. Pictures below. Ideas?

Here you see the reservoir is off the platform, yet the heating element is engaged and the shutoff has not kicked in.



A view of the platform:



Close up view of the switch (reservoir still off the platform)


Edit: looking at the final picture and comparing it to Eric's, it almost looks like only two leads are connected..but I didn't see a wire that was not connected. Maybe it was hiding. I will check again.

Hard to tell exactly, but looks like the retaining nut for the bolt that presses on the switch lever has backed off, probably allowing the screw to back out as well.

There are 3 wires connected, 2 black and 1 violet.
The middle one looks like it's been over heated.

If you lift off the platform, power should go out. If not, bad switch.

I took the platform off completely, still did not cut off the power.

Grr, double post.

If the machine stays on when the platform is lifted check to see that the lever has room to move- that is, remove the reservoir platform and BE SURE that the switch "clicks" as you depress the operating lever, and make sure it clicks again when you release it. If it does then the switch sounds like it is fused in the closed position and the machine should not be used until it is replaced. If you forget to fiul the reservoir even once you risk damaging the heating element.

If it is not clicking when in the "up" position (and in that position it should have a little bit of freeplay), you may need to loosen its mounting screws and lower it a bit so that the lever has free range of motion. After that, it is critical to reset the screw on the bottom of the platform so that the machine turns off before the reservoir is empty. Stefano or Jim can assist you with that adjustment, if necessary.

The reservoir is setting next to the machine. Keep an eye on the water level and it's perfectly safe to use.

cafeIKE wrote:The reservoir is setting next to the machine. Keep an eye on the water level and it's perfectly safe to use....

...if the outer case is replaced.

Randy G. wrote:If the machine stays on when the platform is lifted check to see that the lever has room to move- that is, remove the reservoir platform and BE SURE that the switch "clicks" as you depress the operating lever, and make sure it clicks again when you release it. If it does then the switch sounds like it is fused in the closed position and the machine should not be used until it is replaced. If you forget to fiul the reservoir even once you risk damaging the heating element.

If it is not clicking when in the "up" position (and in that position it should have a little bit of freeplay), you may need to loosen its mounting screws and lower it a bit so that the lever has free range of motion. After that, it is critical to reset the screw on the bottom of the platform so that the machine turns off before the reservoir is empty. Stefano or Jim can assist you with that adjustment, if necessary.

Just getting back to this now (holiday and a vacation away derailed further attempts to fix).

Removed the reservoir platform (the part with the springs & the screw that connects with the switch). The lever has free movement, but makes no clicks. With the platform removed, the top of the lever nearly touches the black rubber disc. Using my finger I can move it up and down, but there are no clicking noises, and nothing happens. Boiler continues to heat normally.

There's a pretty wide range of motion - nearly an inch between the lever's bottom position (when a full reservoir is sitting on the platform) and the top (reservoir platform removed).

(Note: machine worked normally for the last year (in this respect at least...))