# Gaggia Classic problem - steams correctly but coffee below correct temp/pressure?



## michaelcs (Nov 19, 2013)

Good evening. I am a newbie to this forum, but a long-time coffee lover. I have seen past threads but nothing that exactly deals with my symptoms. I have owned a Gaggia Classic for two years (before that inferior Krups machines); it has been regularly descaled; it has always worked perfectly and produced magnificent crema. But since last week, only the left (on/off) light comes on; the right hand (steaming) light doesn't - despite this, the steam/froth function works perfectly. When coffee is demanded hot water comes through the coffee filter but the temperature/pressure are too low so no crema, and coffee is below full strength. Also the sound of the pump strikes me as different.

I wonder if Mark or any other members can advise what part(s) to check first? Is it likely to be the thermostat, or is it the pump, or is something blocked/scaled up?

I have tools and could do most jobs. The pics/tutorial on this forum are excellent - just tell me how to get started.

Thanks everyone/anyone!


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## El carajillo (Mar 16, 2013)

The lower than normal pressure with pump sounding different could be a particle of scale parttialy blocking the solenoid valve.Have you taken the shower screen and dispersion block off and cleaned them ?. AS the ports in the S/valve are very small it only requires a tiny particle of scale to block it.It cannot be blown clear it requires the S/valve taking off and stripping down cleaning and re assembling. The lack of light from steam side could indicate the steam stat is defective/faulty. Can you check the temperature of the water coming from the brew head,run water into a polystyrene cup with a thermometer in .If the temp is low it could be faulty brew stat but it seems odd that they would both go faulty together.

The only other thing that "might" cause low temperature is if one of the heating elements in the boiler is faulty.


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## michaelcs (Nov 19, 2013)

Thank you so much. No I haven't taken anything off yet but will get my tools out and start. 1. What temp should water come out from the brew head? By clean S/valve I suppose I strip and dunk in descaler and reassemble? 3. If one of the heating elements in the boiler has gone, does that mean replace the boiler (which I think is about £45 so I hope not!) 4. Is there an easy way to test the steam stat (have multimeter)?


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## michaelcs (Nov 19, 2013)

Update. Everything now stripped (except I couldn't separate the group from the block, those four bolts are just too tight and I fear the heads will snap if I apply any more pressure - any tips? - dunking the entire assembly in WD40 doesn't seem practicable - would heat help?), descaled and ready to re-assemble.

On my questions above:

1. I don't have a cooking thermometer to test in a polystyrene cup but I have now concluded that my diagnosis was wrong, the coffee still comes out hot enough - but poor tasting and with no crema. Can it be that the water is passing through too quickly, eg that pressure has increased to higher than it was before (perhaps because some blockage has shifted) and I need to run the OPV fix to bring it down to 10 bar??

2. S/valve: I've stripped and cleaned, hopefully any blockage that was there is removed.

3. Let's hope both heating elements are ok and it all works on reassembly.

4. This is the one I would still like an answer to, before I reassemble everything. I have tested the switches with my multimeter and all three are working. Can it be that the brew is in fact happening at the correct temperature and it's just the neon in the brew switch that has failed? Is it possible to test this (can I put 240 volts through that switch? can I remove, test and replace the neon or is it sealed in for life and would I have to replace the whole switch bank?)

But mainly, how can I test the thermostat? On a fridge etc I would hear it click on and off - should that happen here and should it be audible when working correctly? Or if not, how can I test it with a multimeter?

Thanks!


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## El carajillo (Mar 16, 2013)

1 Stale coffee ,too coarse a grind,can both cause rapid through flow and lack of crema.

The pressure does not just increase it has to be adjusted using the over pressure valve OPV, a partial blockage would not increase the pressure.You will need a gauge to adjust the OPV which fits onto the portafilter.

2 Have you completely stripped the solenoid valve, this entails removing the solenoid and thentaking appart the valve including the large nut (19 mm) I think and clean the small components and check the seats and "O" rings

3 Check the heating elements with M/meter set to ohms, the elements are "U" shaped times 2. connect across terminals you should have a reading of about 22 ohms and no reading element to case (earth)

If your test on the swith is positive it could be the neon faulty,I do not think they can be repaired/replaced without the switch.

Temps are shown on side of stats.The only way to test is apply heat to the body with your meter connected across the terminals,the switch should open at specified temp + or-

The difficulty is checking at what temperature this occurs


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