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Thread: VBM Domobar Junior Boiler Pressure

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    VBM Domobar Junior Boiler Pressure

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    I recently picked up a VBM Domobar Junior second hand which was still less than a year old. According to the manual, "On the far left side of the panel is the steam Boiler Pressure Gauge (scale 0.5 to 2.5 bar)... Generally speaking, a reading of about .9 to 1.1 should be expected." However, as you can see in the photo, my gauge ranges from 0 to 4 bar and hovers around 1.5 bar once it reaches steady state. Is this just a case of VBM now using a new gauge and not updating their manuals? Is 1.5 bar the standard setting from the factory or has this been adjusted and is too high?
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    Super Moderator Javaphile's Avatar
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    A quick search of the net, including the manufacturers site, shows a 4 bar gauge on what is presumably the current version of your machine.


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  3. #3
    TC
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    Quote Originally Posted by aushy View Post
    ...Generally speaking, a reading of about .9 to 1.1 should be expected." However, as you can see in the photo, my gauge ranges from 0 to 4 bar and hovers around 1.5 bar once it reaches steady state. Is this just a case of VBM now using a new gauge and not updating their manuals? Is 1.5 bar the standard setting from the factory or has this been adjusted and is too high?
    It's too high. Assuming this is an Australian spec. machine, circa 1.2 bar at top boiler pressure is fine. This of course presupposes that your gauge is delivering an accurate guesstimate of boiler pressure. Scale can cause them to read high/low/not at all...

  4. #4
    Gum
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    Firstly your gauges. They are the same as on my three year old machine.

    As to the boiler pressure, mine rises to about 1.4 to 1.5 when not in use. Before making a coffee I release water for a second or two which brings it down to the top of the green line. It stays around there while making coffees and then creeps up again afterwards.

    I regard my machine as in perfect working order and I suspect yours is too.

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    Quote Originally Posted by Gum View Post
    Firstly your gauges. They are the same as on my three year old machine.

    As to the boiler pressure, mine rises to about 1.4 to 1.5 when not in use. Before making a coffee I release water for a second or two which brings it down to the top of the green line. It stays around there while making coffees and then creeps up again afterwards.
    Why?

    Pressure and temperature are linked in a boiler. With the pressurestat controlling to 1.5 barg the temperature will be at close to it's boiling point at this pressure. When you reduce the pressure to 1.2 barg the boiling point falls. BUT the water temperature doesn't drop instantaneously - the water will boil (cooling in the process) until it reaches the boiling point temperature.

    Meanwhile, the pressurestat will likely have switched the element back on...

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    Quote Originally Posted by Gum View Post
    As to the boiler pressure, mine rises to about 1.4 to 1.5 when not in use. Before making a coffee I release water for a second or two which brings it down to the top of the green line. It stays around there while making coffees and then creeps up again afterwards.
    Thanks for the info. I always purge the grouphead before pulling a shot, however the boiler kicks in around 1.4 bar so there would be no chance that a purge would bring the pressure down to the green line (1.1 bar).


    Quote Originally Posted by Talk_Coffee View Post
    It's too high. Assuming this is an Australian spec. machine, circa 1.2 bar at top boiler pressure is fine. This of course presupposes that your gauge is delivering an accurate guesstimate of boiler pressure. Scale can cause them to read high/low/not at all...
    Machine should be Australian spec. Is there a way to check? I doubt scale would be an issue as the machine was not used very much and only used filtered water. I guess I will reduce the boiler pressure until it gives around 1.1-1.2 bar.

  7. #7
    Senior Member readeral's Avatar
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    Ask the seller who they bought it new from and that'll help you.



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