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Thread: Silvia overheating

  1. #1
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    Silvia overheating

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi all,

    Have had my trusty Silvia for around 5 years. Have looked after her well.

    Recently I feel she is overheating. I will run the water for say 15 seconds and the light indicating the heating cycle will switch on. It has never been so quick to switch on.

    Makes it difficult to brew a coffee as I am forever having to bleed some water in order to get rid of the steam.

    Any help will be greatly appreciated.

  2. #2
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    Anyone, at all?

  3. #3
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    it is overheating so we can assume for the time being it means the element is still working ok, so my first move would be to replace the thermostat.

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    Thanks steve. Which thermostat are you suggesting I replace? The brew thermostat? I can see three. There are two on the top of the boiler and one on the side which activates if you leave the steam wand on etc.

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    Its been a while since I have looked inside a silvia, memory not so good. If your not sure about it maybe better to take it to someone that does? Or download the schematics for your machine and study up.

    How does the machine behave when you try to steam - actually engaging the steaming circuit, if it works as it always has my first instinct would be to just change the brew thermostat as that where you say your having problems.

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    The steam works well with no issues at all. I have worked out which is the brew thermostat. Thanks Steve. I will try this first as it is relatively inexpensive.

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    I replaced the thermostat and while I was it, decided to remove the other thermostat. The outer screw snapped. Great. Will I still be able to use the machine? The other screws were fine.

    It is still overheating

    Everytime I press brew within 10 seconds the light goes and the heat cycle commences

  8. #8
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    This is driving me a little crazy. For years I have been able to enjoy a nice cup of coffee made by miss Silvia.

  9. #9
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    latte_boy, my bet was the same as Steve82's, the heating element's thermostat. You had a spare thermostat? Is it the correct one, not the one with the steam setting? My next suggestion is the same again, get someone to look at because she is still a great machine unless you want an upgrade. Good luck with it, Silvia is worth it.

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    would a PID bypass the thermostat problem?

  11. #11
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    I did replace the thermostat and still the same. How often does silvia heat cycle?

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    Did you notice any scale when you replaced the thermostat? Just wondering if scale in the boiler, element, etc could cause it to do what you're describing.

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    Just ran a test on my Silvia, had been switched on for 25 to 30 min. With the machine up to temp (light off) and with no portafilter in the group, I seem to get about 15 to 20 seconds of full flow before the heater kicks in again (light switches on). However with no portafilter (and no bed of coffee to flow through) this equates to 160ml of water dispensed (as weighed). How does yours compare in this regard?

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    Mouldy, I might try de scaling again. Any suggestions as far as the better methods of descaling and products used? Have just switched the silvia on, will monitor and time how long it takes for the light to switch on

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    Quote Originally Posted by latte_boy View Post
    Mouldy, I might try de scaling again. Any suggestions as far as the better methods of descaling and products used? Have just switched the silvia on, will monitor and time how long it takes for the light to switch on
    I've not descaled my Silvia, but on the commercial machine rebuilds I've done, I've removed the complete boiler and descaled in citric acid solution. Not sure if it's a recommended method for Silvia though as I suspect it's not overly easy to do so on this machine. I'm not even sure what material the Silvia's boiler is constructed from.

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    I believe it contains a brass boiler.

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    Senior Member artman's Avatar
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    Yes brass boiler. Easy to descale in situ, just do a search. Make sure you use an appropriate descaler that dissolves the scale instead of lifting flakes that can then get stuck somewhere.

    Cheers

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    That does sound like the type of de scale needed. Do you have a name or brand? I have looked online but am yet to come across any information as far as dissolving instead of lifting flakes.

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    I've always had success with Cafetto Restore. It does the job for most scenarios.
    Site sponsor Coffee Parts sells the individual satchets or boxes of 4, they're pretty good value.

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    I tend to buy pure citric acid granules. It can be found in many craft and chemical supply stores. The 4kg bucket of citric acid granules I purchased was about $35, and smaller bags are available (1kg about $11). I have found that the purpose marketed products are very much more expensive; however they tend to use stronger acids (like Sulfamic, hydrochloric, etc), so probably a bit quicker descaling for a given concentration.

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    Quote Originally Posted by artman View Post
    Yes brass boiler. Easy to descale in situ, just do a search. Make sure you use an appropriate descaler that dissolves the scale instead of lifting flakes that can then get stuck somewhere.

    Cheers
    Quote Originally Posted by Mouldy View Post
    I tend to buy pure citric acid granules.
    ....which will lift scale off in flakes. Not appropriate unless you're disassembling and soaking bits in a bucket.

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    Quote Originally Posted by Talk_Coffee View Post
    ....which will lift scale off in flakes. Not appropriate unless you're disassembling and soaking bits in a bucket.
    This is just not the case in my experience. Citric acid has dissolved scale on the boilers I have removed for that purpose. I've not seen flakes left in the solution when I've removed items from the bucket after descaling typical boiler carbonates. It works on the same principle as other acids for this purpose; which is that the carbonates are soluble in acidic solutions.

    Would be good if a chemist could step in and confirm either way the chemical reactions and products resulting. Perhaps different types of boiler materials and scale compounds can affect results?
    Last edited by Mouldy; 28th July 2014 at 08:13 PM.

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    Interesting points of view. I am more curious now.

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    I think perhaps the time each solution has to work in is a contributing factor. If you're soaking a boiler and components, it's probably going to be in there for several hours. However, if you're descaling a boiler with the element still inside, descaler sitting in the pump/tubing etc. then it's not going to stay in there quite as long.
    If I am running a descale on a heavily scaled thermoblock machine, one sachet of Cafetto Restore into 1 lt of water will be strong enough to start acting on the scale within 10 minutes.

    I think that the domestic descalers, for use in closed systems like small boilers and thermoblocks, are faster acting to dissolve the scale more rapidly. However, citric acid can pull the scale off the metal in a short period of time but can take longer to actually dissolve it.

    I have no scientific evidence to back this up, just sounds like it might be plausible?

  26. #26
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    There is some great information in this document;

    http://users.rcn.com/erics/Water%20Q...ater%20FAQ.pdf

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    I have descaled and it has improved. Seems to switch on faster than it used to but now not as quick as it did last week. Thank you everyone for your tips, advice and help
    Dimal likes this.

  28. #28
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    The Silvia really is a very simple machine. Unless you are a total klutz you can remove the boiler yourself and clean it properly, you only need a few simple tools. Take photos as you go to make assembly simpler.



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