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Thread: Low steam pressure on Giotto Rocket PP (2009) - advice please?

  1. #1
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    Low steam pressure on Giotto Rocket PP (2009) - advice please?

    Hi Coffee Snobbers,

    Thanks in advance for any advice I receive!

    I have a 2009 Giotto Rocket PP (Sirai PS) which has started having low steam pressure issues. It seems to have happened all of a sudden and I'm at a loss to work out what has caused it. The machine is back flushed with water each night and chem flushed every couple of weeks. We use filtered rain water to fill the tank. The pressure seems to start around 1.3-1.4 at the start of the steaming process and drops to around 1-1.1 bars during steaming. From memory, this is similar to what it has done in the past but the pressure from the wand just appears weak and it's taking me much longer than usual to steam. I'm steaming around 200ml in a 350ml jug which is taking around 40 seconds, it used to take half that. I'm struggling to get the milk to swirl much at all in the jug when tilted and I'm not getting the thick micro foam I used to.

    So far I've checked the following:

    1.) steam pressure gauge is showing that the machine is cycling between 1.2-1.4 bars pressure. Seems ok.
    2.) thoroughly cleaned steam wand, the holes in the end of steam wand and the copper pipe between steam valve and boiler using a pipe cleaner. No sign of any blockages there.
    3.) I have checked the that the boiler is not overfilling by cleaning boiler probe and ensuring it's pushed down far enough into boiler. Also there's no spluttering of water from the vacuum breaker.
    4.) I've turned the machine on from cold with the steam wand open to clear any air pockets out (I read somewhere this can sometimes cause issues).
    5.) I've checked the screen at the top of the group head and no signs of any scale build up.

    I can see a little bubble of water forming on the vacuum breaker valve and sometimes this bubbles a bit, not much though. Could this be the issue, a leaking vacuum breaker? if so, shouldn't the steam pressure shown on the gauge reflect a loss in pressure?

    Is there something else I'm missing here?

    Thanks again for any advice!

    cheers, Jonny

  2. #2
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    Hi Jonny,
    check the silicone hose in the steam wand isn't blistered - remove to check - this can reduce steam output on a machine that is up to correct pressure.
    Jonny likes this.

  3. #3
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    Quote Originally Posted by dino View Post
    Hi Jonny,
    check the silicone hose in the steam wand isn't blistered - remove to check - this can reduce steam output on a machine that is up to correct pressure.
    Thanks for your response dino!

    I removed and checked the silicone hose but it looks good, no signs of blistering.

  4. #4
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    try steaming without silicone tube in the wand??
    Jonny likes this.

  5. #5
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    When I steam with my Rocket/Giotto the boiler pressure starts around 1.3 and drops to about 0.8 and stays there. I steam around 450 ml of milk (2 large cups). If your boiler pressure remain as high as you say then there is a blockage somewhere in the line. It could be closer to the boiler, but my immediate feeling it is in or on the boiler side of the steam valve. I am having a similar problem with the hot water valve. There is a build up of scale and the flow is very restricted.
    So check an see if you get a good pressure from the hot water valve, that will indicate that the boiler is ok.
    As regard to repair, it will most probably require the removal of the internal copper pipe to the valve to remove the scale on the boiler side of the valve. It may also be wise to give the steaming valve a very good clean to remove any other scale. It may be a service job as there is a risk of over tightening the internal copper/brass fittings.
    Jonny likes this.

  6. #6
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    Quote Originally Posted by dino View Post
    try steaming without silicone tube in the wand??
    I had a more thorough feel of the silcone tube this morning Dino (yesterday must have been a boys look) and could feel a slight lump about 3/4 of the way along. Yesterday I was looking for some sort of perish marks, something visible from the outside but I think this lump is what you were probably referring to. I cut the tube off before the lump and re-installed it and pressure is back to max! Thanks so much, you've made my year!!! I'm guessing the silicone tubing is part of the cool touch mechanism for the milk wand. If so, would it matter much if the last few cm is missing?
    Dimal likes this.

  7. #7
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    Quote Originally Posted by dumiya View Post
    When I steam with my Rocket/Giotto the boiler pressure starts around 1.3 and drops to about 0.8 and stays there. I steam around 450 ml of milk (2 large cups). If your boiler pressure remain as high as you say then there is a blockage somewhere in the line. It could be closer to the boiler, but my immediate feeling it is in or on the boiler side of the steam valve. I am having a similar problem with the hot water valve. There is a build up of scale and the flow is very restricted.
    So check an see if you get a good pressure from the hot water valve, that will indicate that the boiler is ok.
    As regard to repair, it will most probably require the removal of the internal copper pipe to the valve to remove the scale on the boiler side of the valve. It may also be wise to give the steaming valve a very good clean to remove any other scale. It may be a service job as there is a risk of over tightening the internal copper/brass fittings.
    Thanks so much for your thoughts and advice Dumiya, much appreciated! Dino was on the money with the silicone tube blistering but I thought looked good from the outside...inside it seems it was a different story! Thanks again though, I really love all the helpful advice on this forum.

  8. #8
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    good to see you are back steaming at full pressure

  9. #9
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    Quote Originally Posted by dino View Post
    good to see you are back steaming at full pressure
    Can't wipe the smile off my face dino!! Thanks again!!

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