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Rocket Giotto V3 Premium PID can't sustain steam pressure

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  • lionbarista
    replied
    Just to add to this old post.
    I've recently replaced the stock 2 hole to a aftermarekt 4 hole on my giotto. The steam power is now almost the double which I absolutely love and much easier for me to steam good milk as it's a closer power as commercial machines I use at work.
    The pressure on my giotto does indeed drop to about 0.7bar from 1.1ish from about 5 seconds into the steaming and it is annoying. However, I still think it is far superior than the stock 2 hole and the results speak for itself.

    Leave a comment:


  • blazer78
    replied
    Originally posted by wattgn View Post
    Edit: It could be the rate of draw down of the boiler too, steam flow affecting it too.
    Quite possibly! It is an interesting issue in anycase, and I will continue experimenting.

    Leave a comment:


  • wattgn
    replied
    Originally posted by blazer78 View Post
    Yes, they are optional accessories (which I had purchased for curiosity sake, along with LM GB5 wand and Sproline Foam Knife 1 + Vortex). They have a newly designed 2-hole steam tip where the holes are oriented in the same direction to spin the milk easier. I've had the best results with the new 2-hole tip as well as the 4-hole, but it still doesn't quite match the boutique cafes using a commercial machine.

    Unlike your wega however, the Rocket definitely does not take anywhere near as long as 15 seconds to recover from 0.7BAR.
    It is just physics. If the boiler is the same size and the heater element is the same wattage, it will take the same time. It isn't a brand or prestige thing. It is just physics. My 20 year old Bezzera will kill anything with a 2L boiler as the boiler is twice the size and twice the heating elements.

    Edit: It could be the rate of draw down of the boiler too, steam flow affecting it too.

    Leave a comment:


  • blazer78
    replied
    Originally posted by samuellaw178 View Post
    If the pressure drop is less it'd be an easier learning curve for beginners...not everyone starts out as a barista champion Didn't Rocket come with a set of steam tips (or are they extra accessories)?
    Yes, they are optional accessories (which I had purchased for curiosity sake, along with LM GB5 wand and Sproline Foam Knife 1 + Vortex). They have a newly designed 2-hole steam tip where the holes are oriented in the same direction to spin the milk easier. I've had the best results with the new 2-hole tip as well as the 4-hole, but it still doesn't quite match the boutique cafes using a commercial machine. I have no problems attaining results with the LM linea classic 3-group and its stock 4-hole tip though.

    Unlike your wega however, the Rocket definitely does not take anywhere near as long as 15 seconds to recover from 0.7BAR.

    Leave a comment:


  • wattgn
    replied
    The number of holes of course don't determine velocity and flow rate. I had a four hole one for my Bezzera that would froth 600 mls of milk in 15 seconds. It flows a lot quicker than the four holed one on the Wega.

    Leave a comment:


  • gonzo89
    replied
    Well that answers the question Chris, it's certainly not a stock item ;-) I was trying to get used to a 4 hole but didn't like the results. All along I should have just stuck with the two stock steamtips as they work very well.

    Well I'm glad to hear it's not just me who doesn't enjoy 4 hole steamtips in a domestic setting.

    Leave a comment:


  • TC
    replied
    Originally posted by gonzo89 View Post
    I hate the 4 hole steam tip on the r58..
    It ships standard with a 2 hole gonzo89... Where did your 4 hole come from?

    FWIW, about the only 4 hole I have ever used and liked (other than where necessary on commercials) is the stock LM style as found on the GS3/Linea mini/Slayer 1GR.

    Leave a comment:


  • gonzo89
    replied
    I agree with the comments about using a tip that the user is more likely to get the hang of once they have the technique down. I hate the 4 hole steam tip on the r58. Yes it is faster but the texture isn't as good. Could be my inexperience with 4 hole tips I admit.
    I always run a higher bar for steaming. Why bother with less power? It doesn't do anything better. As mentioned by wattgn, use a smaller hole tip perhaps for a little more control. And as Chris mentioned, purging the wand longer to get the PID to kick in is a way to get a more stable pressure throughout steaming. I give my r58 wand a very long purge or else I don't like the results.

    Leave a comment:


  • wattgn
    replied
    The best tip is a matter of opinion. I had a five hole tip ship with my Wega. I swapped it for a four hole tip which is better. Honestly for the amounts of milk I typically do I would prefer even less flow but higher velocity.

    I could have got by with the five hole tip but it froths so quickly, it takes more skill and timing than a slower tip where you have 30 - 40 seconds to leisurely froth the milk.

    I suspect they like to give you a high flow tip so when reviewers test it, it looks good in terms of the time it takes to froth the milk.

    Leave a comment:


  • TC
    replied
    Originally posted by samuellaw178 View Post
    He's asking if it's normal. So it is normal....
    Perhaps, or perhaps not. Flaky technique can amplify these types of issues. The best solution would be training and to have the machine checked to confirm that it's operating normally- which it should be if it was bench tested by the seller. In addition, the PID set temp increase as suggested will assist.

    Didn't Rocket come with a set of steam tips (or are they extra accessories)?
    They're accessories but not required IMHO. The Giotto already ships with the best tip option.

    Leave a comment:


  • samuellaw178
    replied
    The OP is not blaming the tools here... He's asking if it's normal. So it is normal.

    If the pressure drop is less it'd be an easier learning curve for beginners...not everyone starts out as a barista champion Didn't Rocket come with a set of steam tips (or are they extra accessories)?

    Leave a comment:


  • TC
    replied
    My experience is that when buyers have difficulty with milk texture on a perfectly adequate machine, it's technique.

    There's nothing wrong with the giotto wand or tip. The combo is in fact one of the best in the business.

    The OP could set the PID to allow for a 1.2Bar max or thereabouts (approx 123 deg. C). in addition, a squirt from the steam valve before the shot is pulled will wake the PID and have it doing its thing to bring the element in.

    Sometimes the tradie blames the tools...

    Leave a comment:


  • samuellaw178
    replied
    If that is indeed the case, then it is the last option : iv) The steam tip is not optimized for the machine. I would be surprised it wasn't picked up by the vendors on this high end home machine that had received lots of improvisation over the years. In a market where most drinks end up being milk coffees, 350mL is not a big amount to ask for...

    Big boiler is one thing, ideally you also want to keep the steam tip orifice matched to your element heat output. http://www.home-barista.com/levers/o...ps-t27312.html

    Too much pressure drop is not good for microfoam texture as you need more power in the end for whipping/breaking the froths.


    Addition: So I stand corrected. That much pressure drop seems normal for a Rocket Giotto.... https://www.youtube.com/watch?v=7fGUppjxx94
    Last edited by samuellaw178; 3 October 2016, 06:09 PM.

    Leave a comment:


  • wattgn
    replied
    It is normal.

    This behaviour is what I've seen on every similar size machine.

    Reality check. These are still small home machines made for relatively small amounts of milk and yes, you will see a substantial drop in steam pressure once you open the valve.

    It isn't true to say you can go from .5 Bar to 1.1 Bar in a few seconds. For that to happen the water would have to heat 2L of water 10C or so almost instantaneously.

    I experimented with my Wega Mini Nova Classic which has a 2.1 L boiler and 1400W element similar to the Giotto. If I do 15 seconds with my four hole tip, it goes down to 0.7 Bar and takes about 15 seconds to recover (as the element turns on as soon as the pressure drops). This would simulate heating a small amount of milk. Obviously if I use a fine tip then the pressure will stay high in the boiler due to the lower flow.

    Same results as the OP with his Giotto, just needs to use a tip with lower flow and higher velocity if he wants to improve froth.

    Leave a comment:


  • samuellaw178
    replied
    Doesn't sound normal to me.

    Just throwing out some possibilities:

    i) Most likely your vacuum breaker valve is sticking closed and accumulates false air pressure. Try purging the steam for 10 sec full blast and let it get back up to 1.1 bar, before doing the actual steaming. See if it improves.
    ii) The autofill probe is set incorrectly - resulting a low water level.
    iii) PID setting is incorrect - doesn't allow enough juice to the heater to sustain pressure when steaming.
    iv) The steam tip is not optimized for the machine. Quite unlikely for a Rocket...

    Except for option i. The others require more thoughts and probably a tech to look at it.

    Leave a comment:

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