# Grey sludge from Gaggia Classic - decaying boiler?



## jamster (Feb 6, 2014)

Hello all - I need your help again!

Our Gaggia Classic is emitting grey sludge after backflushing.

I've noticed that the grey thermoblock seems to be badly decayed & seems to be emitting the grey sludge. (I took it apart and scraped off the grey goo, but it seems to be back).

If this is happening, is it fair to say the boiler is shot too? Or do you think I can replace the thermoblock and carry on enjoying the machine?

Cheers!


----------



## DavecUK (Aug 6, 2013)

jamster said:


> Hello all - I need your help again!
> 
> Our Gaggia Classic is emitting grey sludge after backflushing.
> 
> ...


Probably time to end your relationship with the classic and look for something new.


----------



## El carajillo (Mar 16, 2013)

When you say thermoblock are you referring to the distribution block /plate behind the shower screen? What are you using for back flushing and how often

some cleaners cause a reaction between the block and the brass nut in the centre of the block. It is better to take it off and scrub it with a brush and hot water. The aluminium block is also attacked by the acidic coffee.

This is why many members have changed the block for a brass one .


----------



## jamster (Feb 6, 2014)

Yes - apologies - I mean the distribution block.

I was not aware to backflush until recently. I did occasionally disassemble and clean the block. I've been descaling using calcinet (hopefully in the right dilution).

If the calcinet caused the problem - will it have wrecked the boiler too?

Or can I safely exchange the alu block for a brass one?

Keen not to ingest too much aluminium


----------



## El carajillo (Mar 16, 2013)

Calcinet is very aggresive and is better used for commercial machines, I would suggest you get something more suitable for your Classic.

It will not have affected the boiler as back flushing cleans the brew head and back through the S/valve down into the drip tray.

Changing for a brass distribution block would be a good step to take.

It is wise not to back flush too often with cleaner as GAGGIA (do not recommend back flushing) although most people do.

Carry on and enjoy your coffee.


----------



## Wando64 (Feb 28, 2011)

jamster said:


> Keen not to ingest too much aluminium


I was having the same problem (sludge) and worries (alluminium) when I was using a Baby Gaggia.

After taking the boiler apart and seeing the huge amount of corrosion I concluded I just needed to move away from alluminium boilers.


----------



## jamster (Feb 6, 2014)

Interesting thanks Wando. What did you replace it with? I'm looking at a Cherub but the footprint is probably too big for our small kitchen.


----------



## Wando64 (Feb 28, 2011)

Rancilio Silvia V3


----------



## jamster (Feb 6, 2014)

Thanks all - in the end I've decided to upgrade to a Cherub.

The Gaggia has served us well but I'm keen to continue on the coffee journey.









Much appreciate the help.


----------



## bpowell555 (Nov 30, 2014)

Wando64 said:


> I was having the same problem (sludge) and worries (alluminium) when I was using a Baby Gaggia.
> 
> After taking the boiler apart and seeing the huge amount of corrosion I concluded I just needed to move away from alluminium boilers.


Can't let this go unanswered. I have had a classic for 6 years. Prior to that it was on ebay and didnt exactly look new when I got it. Bought for £85. I replaced the portafilter gasket and cleaned everything up with pulycaf and have backflushed about once a month since. Recently I flush the group and rinse the tray before I switch it off. I've descaled it maybe 3 times - soft water area. This year I also pimped in the brass dispersion plate and a new shower screen.

While I always had some noticeable grey flecks in a cup of water - still better than from my kettle - its got no worse in that entire period. So, I would suggest if you're getting grey sludge from the Classic then it is categorically nothing to do with the aluminum boiler, rather it is what sounds like a quite grotesque lack of knowledge of basic maintenance. Sorry if I appear rude, but I don't like to see quality engineering insulted by an amateur.

By any measure the value and reliability I've had from my Classic is astronomical. Sure I'm thinking of swapping the boiler but even after probably 8 years on these machines I don't think its necessary.

Cheers!


----------



## AL3XTUDOR (Nov 17, 2014)

You should descale as often as reasonably possible!


----------



## hotmetal (Oct 31, 2013)

AL3XTUDOR said:


> You should descale as often as reasonably possible!


Not really. Especially with an aluminium boiler. Better to feed it with low TDS bottled water, RO water etc to minimise scale build up, and descale when necessary, say maybe twice a year depending on how much use you give it. Although descaling a single boiler machine is easy, it doesn't mean you should do it every weekend!


----------



## Wando64 (Feb 28, 2011)

bpowell555 said:


> Can't let this go unanswered. I have had a classic for 6 years. Prior to that it was on ebay and didnt exactly look new when I got it. Bought for £85. I replaced the portafilter gasket and cleaned everything up with pulycaf and have backflushed about once a month since. Recently I flush the group and rinse the tray before I switch it off. I've descaled it maybe 3 times - soft water area. This year I also pimped in the brass dispersion plate and a new shower screen.
> 
> While I always had some noticeable grey flecks in a cup of water - still better than from my kettle - its got no worse in that entire period. So, I would suggest if you're getting grey sludge from the Classic then it is categorically nothing to do with the aluminum boiler, rather it is what sounds like a quite grotesque lack of knowledge of basic maintenance. Sorry if I appear rude, but I don't like to see quality engineering insulted by an amateur.
> 
> ...


Which bit of "*after taking the boiler apart and seeing the huge amount of corrosion*" did you not understand?

Indeed you "appear rude", however spare me the "sorry" bit please.

Welcome to the forum. Nice second post.

Have a nice day.

In case you or anyone else is interested, here is a link to the original thread discussing my issue with the Baby. http://coffeeforums.co.uk/showthread.php?7689-Black-dust-debris&p=53216#post53216


----------

