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Thread: Expobar Office Leva losing pressure

  1. #1
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    Expobar Office Leva losing pressure

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hello guys,

    I have recently replaced the element on my expobar and in the process fixed a leaking valve. Now when the machine has had 1/2 an hour to warm up the element still switches on 70 seconds. To me this seems too short for the boiler to cool down. Incidentally I do live in Norway now however the temperature inside the house is comparable to that in Australia. I have a feeling that there may be a loss of pressure but am not sure.

    How long do your boilers take to cycle? I know there are some leva owners here so I am checking if I am over reacting. If there is a problem where is the best place to look as there are no audible hisses of escaping steam and the insulation is still in good condition. Any help is appreciated. Cheers.

    samthedog.

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    Sleep is overrated Thundergod's Avatar
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    Re: Expobar Office Leva losing pressure

    sam do you mean it switches on 70 seconds after it last went off?

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    Re: Expobar Office Leva losing pressure

    Yes TG, thats correct. every 70 seconds the boiler turns on. Gee you have been busy mate, thats alot of posts. How does this compare to your leva?

    samthedog.

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    Re: Expobar Office Leva losing pressure

    Just finished timing it for you.

    I forced it to cycle by drawing out some hot water.

    After the first reheat it then took approx. 90 seconds before it hetaed again for about 13 - 15 seconds.

    The next cycle was about 2 minutes later. Again for about 14 seconds.

    Next cycle 2 minutes 4 seconds.

    So it would appear that mine cycles on for about 14 seconds every 2 minutes and 4 sec.

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    Re: Expobar Office Leva losing pressure

    If I draw water, when the light turns off it takes less than 40 seconds for the boiler to turn on again. I have no idea whats causing this loss of pressure. I cant hear any leaks. Where could I be losing the pressure from?

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    Senior Member Lovey's Avatar
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    Re: Expobar Office Leva losing pressure

    Gday Sam,
    I just did some timings of my Giotto and the cycle is as follows:
    On for 7-8 seconds
    Off for 43-44 seconds
    The dead-band is between 0.9 and 1.1 bar.
    Youre machine probably isnt leaking, you might just have a tight dead-band pressurestat.

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    Re: Expobar Office Leva losing pressure

    Thanks for the info Lovey. How does that affect the temperature stability? Does this mean that the pressure stat is more sensitive thus forcing the boiler to turn on more often to keep a constant pressure?

    samthedog.

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    Re: Expobar Office Leva losing pressure

    How long does it stay on for?

    If Lovey is correct and its just a tight deadband, then Id expect it to stay on for only a few seconds.

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    Re: Expobar Office Leva losing pressure

    Quote Originally Posted by samthedog link=1191660653/0#6 date=1191670447
    Thanks for the info Lovey. How does that affect the temperature stability? Does this mean that the pressure stat is more sensitive thus forcing the boiler to turn on more often to keep a constant pressure?

    samthedog.

    samthedog,

    Yep, pressurestats are far more accurate than thermostats and maintain a far more constant temperature.

    Not all pressurestats are created equal however.... they all have a "dead band" - the gap between switching off and switching back on again and that is generally 0.2 bar or less.... and the smaller that is - the more constant is the temperature.

    But even those with a broad dead band are still much better than a thermostat.... and it generally means they will switch more often..... although my two group with a dead band just over 0.1 bar is on for 20 seconds and off for 220 seconds (with a 17l boiler).

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    Re: Expobar Office Leva losing pressure

    The element is on for 6 - 8 seconds TG. It seems that the pressure stat drops fast but it only takes seconds to bring it back up again. I was wondering if I compressed the insulation a bit when I changed the element and this may have some bearing on it too. I would have though all expobars are created "equal" and that it would not differ so much from machine to machine. Mine seems to follow Loveys Giotto rather than an Expobar.

    To sum up, does this seem "normal"?

    samthedog.

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    Senior Member Lovey's Avatar
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    Re: Expobar Office Leva losing pressure

    Gday Sam,
    I just did another time test for you to compare to last nights, and the cycling times are a bit different now.
    On - 7 seconds (no change).
    Off - 62 seconds.
    I attribute this change to the different ambient temperature in the room, ie 9pm last night to 11am today, which may be about 10 degrees.
    Although the room temperature there may be similar to here is Aus, as you can see the room temps can change, which will affect your boiler cycle timings.
    My giotto boiler isnt insulated, and is more susceptible to changes in ambient temps though.
    I wouldnt worry about your machine, the timings sound good. If you had a leak somewhere, you would definitely hear it as a hissing noise, and you would probably have water puddles underneath the machine as the steam condenses and falls through the machine.
    All the best.

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    Re: Expobar Office Leva losing pressure

    Does seem normal to me as well.

    Your "on" time is less, as I expected with the shorter interval as compared to mine.

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    Re: Expobar Office Leva losing pressure

    Sweet.Thanks for the replies guys, I appreciate it. I was starting to panic a bit as coffee machines of this type are rare here and I really didnt want to run into any problems.

    The leaky valve I had was the one that closes as the boiler pressure increases. You initially hear it as the boiler turns on for the first time. The valve has a moving "bung" in it that pushes up with steam pressure o close off against a nylon sleeve. The nylon sleeve did not seal against the brass housing so that even when the bung closed firm against the nylon, pressure escaped between the nylon and brass housing. This resulted in a hiss and a quite rapid loss in pressure. I solved this by taking out the nylon sleeve and placing some plumbing tape around it and securing it back in place. I also lubricated the small rubber o ring on the bung with a food grade high temperature/high pressure grease so that it would slide up and house correctly without catching anywhere.

    I just hope everything runs smooth from here on as I wont easily find a replacement on this side of the world.

    samthedog.

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    Senior Member Lovey's Avatar
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    Re: Expobar Office Leva losing pressure

    Quote Originally Posted by samthedog link=1191660653/0#12 date=1191755036
    Sweet.Thanks for the replies guys, I appreciate it. I was starting to panic a bit as coffee machines of this type are rare here and I really didnt want to run into any problems.

    The leaky valve I had was the one that closes as the boiler pressure increases. You initially hear it as the boiler turns on for the first time. The valve has a moving "bung" in it that pushes up with steam pressure o close off against a nylon sleeve. The nylon sleeve did not seal against *the brass housing so that even when the bung closed firm against the nylon, pressure escaped between the nylon and brass housing. This resulted in a hiss and a quite rapid loss in pressure. I solved this by taking out the nylon sleeve and placing some plumbing tape around it and securing it back in place. I also lubricated the small rubber o ring on the bung with a food grade high temperature/high pressure grease so that it would slide up and house correctly without catching anywhere.

    I just hope everything runs smooth from here on as I wont easily find a replacement on this side of the world.

    samthedog.
    No worries Sam,
    the part youre referring to is called an "anti-vacuum valve".
    Heres a link to a CG thread which is about the same anti-vac valve, scroll down to the bottom of the page and youll see an exploded view of the valve.
    http://www.coffeegeek.com/forums/esp...achines/319911

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    Re: Expobar Office Leva losing pressure

    Quote Originally Posted by samthedog link=1191660653/0#12 date=1191755036

    I just hope everything runs smooth from here on as I wont easily find a replacement on this side of the world.
    I think youre closer to Spain than I am.

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    Re: Expobar Office Leva losing pressure

    Cheers Lovey, thats the culprit. I could have fixed the sleeve in place with a special loctite however that would have made pulling it apart to replace the o ring impossible for the future. As for being closer to spain Tg.... A Rancillio Silvia here costs over $1100, and HX machines are literally unknown amongst the consumer market. I could only buy fresh coffee beans in Oslo and even then many of the blends were terrible. I am paying $40 a kilo for coffee beans and more for premium beans such as PNG or Guatemala. In many cafes here when you order coffee they serve black instant and charge you the price of cappa or latte. Its a strange place...

    samthedog.

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    Senior Member Lovey's Avatar
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    Re: Expobar Office Leva losing pressure

    Quote Originally Posted by samthedog link=1191660653/15#15 date=1191764779
    As for being closer to spain Tg.... A Rancillio Silvia here costs over $1100, and HX machines are literally unknown amongst the consumer market. I could only buy fresh coffee beans in Oslo and even then many of the blends were terrible. I am paying $40 a kilo for coffee beans and more for premium beans such as PNG or Guatemala. In many cafes here when you order coffee they serve black instant and charge you the price of cappa or latte. Its a strange place...

    samthedog.
    Strange indeed,
    it sounds sort of familiar,
    aaahhh thats it, HELL ;D.



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