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Thread: Boiler pressure drop

  1. #1
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    Boiler pressure drop

    I've got an ECM Mech IV profi , over 4 years old, and for the last couple of days the boiler pressure rapidly drops ( 2-3 seconds) to 0 when using the steam lever. The pressure builds back up within a minute, and the drop doesn't occur with further use during the day. Machine on as usual for about an hour before use. Any ideas on cause ?

  2. #2
    Super Moderator Javaphile's Avatar
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    Your anti-vac valve isn't doing its' job.


    Java "False pressure" phile
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    I thought it might be the culprit, but why only the first use, and not subsequent use of steam ?

  4. #4
    Super Moderator Javaphile's Avatar
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    For the same reason the anti-vac valve is only used once when the machine is first turned on for the day. Once you open the steam valve you relieve the false pressure. (This term is actually a misnomer as the pressure is real but the air in the boiler is dry rather than saturated.) When you turn off the machine and it cools down the moisture condenses out of the air in the boiler and with the anti-vac valve not opening when the pressure falls that now dry air is trapped in the boiler and doesn't reach saturation. Opening the steam valve after the boiler heats up after the machine is turned on again allows this dry air out and as the pressure in the boiler drops steam is flash produced saturating the air in the boiler as the water in the boiler is above the boiling point at the now lower pressure. Once saturated it remains saturated until the machine is turned off and the boiler cools and the steam in the air condenses out repeating the whole cycle again.


    Java "Where's Bill Nye when you need him" phile
    trentski likes this.
    Toys! I must have new toys!!!

  5. #5
    Senior Member artman's Avatar
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    Because a vacuum is created which you clear the first time you crack the steam valve.

    Cheap and easy fix you can diy if you are that way inclined.

    Cheers

  6. #6
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    Thanks for the help. Just need to order a new anti-vac valve then. Until I get a new valve, is there any chance of damaging machine by just opening steam valve when up to temp ?

  7. #7
    Super Moderator Javaphile's Avatar
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    Many anti-vac valves can be cleaned to get them working again. Or even just pushing down on the shaft sticking up out of the top of the valve to unstick it can get it working again. You may be able to clean and rebuild the valve rather than replacing it for a fraction of the cost. Most valves have an internal gasket or o-ring that can be replaced after they've been cleaned to get them working properly again.

    As to the possibility of damaging your machine the biggest risk is when the machine cools down. If the anti-vac valve doesn't open the possibility exists that the boiler could collapse in on itself from the vacuum generated as it cools. Opening the steam valve once the boiler has heated up is not a problem.


    Java "Give the valve shaft a poke" phile
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  8. #8
    Senior Member artman's Avatar
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    As above, it's a very simple device. The ones I have seen are simply a rod inside a sleeve with an o ring. Mine failed with the O ring going hard. Easily replaced for a few cents. I bought a few (from bearing supply shop) to keep for future.

    The entire valve is not that pricey either.

    As above, a quick poke from the top the valve will unstick it.

    Cheers

  9. #9
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    Unscrewed the valve, rinsed it out , put it back in and have cycled machine twice and it seems to be working again. See how it goes after getting completely cold overnight, was body temp only today.
    Didn't see any o ring either, the bottom bit of the plunger that seals is some sort of rubbery stuff, about 2-3mm thick. Looks different to pictures of others which appeared to be all metal.
    Thanks again, hope all goes well tomorrow

  10. #10
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    I trust you will have solved the problem. Let's know as there is another thing that caused this for me that isn't quite as simple to fix.

  11. #11
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    No problems this morning, so it looks like taking it off and rinsing it has fixed it. Hopefully stays that way.
    Dimal likes this.

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