Replacing the pump on a Gaggia Classic Coffee ('95)

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
gaggiaDIY

Postby gaggiaDIY » Jan 11, 2019, 4:34 pm

Hello fellow coffee lovers!

So we found a very cheap (and very old) Gaggia Classic Coffee espresso machine. It's from 1995, I think. The base is pretty rusty and we had to do a thorough cleaning and de-scaling, but it works pretty well now. Except the pump is pretty worn out, it's leaky and noisy. We'd like to replace it, but... with what? Currently the machine has an Eaton CP2 pump and these appear not to be available anymore. I was hoping somebody here knows what to replace it with?
There's a sticker on the pump that says (among other numbers):
240V ~ 70 W 1min/1.5 min
220V ~ 50Hz/60W 1min/1min
95/19 CL7

Any help would be appreciated!

myso

Postby myso » Jan 11, 2019, 5:06 pm

I was making a small research for restoring/maintaining my 10+ year old gaggia evolution.
On the website below it says ulka ep5gw is slightly stronger than ex5. (X for brass P for plastic)
https://www.mrbean2cup.co.uk/general-ul ... 230v-ep5gw
Ulka website classifies ep5gw as special for gaggia coffee machines. And I saw on eBay also a model named ex5gw. :?
But ulka e5 range is widely used. Check the class of the pump and prefer f class of higher and don't buy a class. F class models have 2min on / 1 min off duty cycle whereas a class models have 1min on / 1 min off.

Other option is ars invensys pumps. My Evo lists it on the part diagram: "invensys cp3a 230/50".
I didn't make research on them but I read somewhere from someone who installed a dimmer circuit to keep the pump at lower power to decrease the pressure. He said his ulka e5 stopped working with dimmer anymore and the invensys pumps are better for the dimmer application.

I would like to hear of comparison between ulka and invensys.

gaggiaDIY

Postby gaggiaDIY » Jan 11, 2019, 6:36 pm

Thanks! I have been looking at the Invensys pump on eBay. It appears to come close to the original in specs.
The Ulka pump is cheaper/easier to find in The Netherlands. But it's 48W, while the original Eaton pump is 60W. Wouldn't that be a problem, somehow?
What does it mean to have a 2min/1min cycle? In what way is it better? Thanks for your help!

myso

Postby myso » Jan 11, 2019, 6:47 pm

I will quote from someone else. Bear in mind 110V/60Hz EX5 is class A but 230V/50Hz EX5 is class F.
lancealot wrote:{...}
OK, so after studying the spec sheets from CEME (maker of ULKA). I finally cracked the code. The "F" and the "A" is the insulation class.
After a quick search on solenoid insulation class specs (we call them vibe pumps but they are actually solenoid pumps), I figured out that the higher the letter, the higher the temperature rating of the insulation in the coils. SO "F" is better than "A".

Check the duty cycle to see what I mean. The EFP5 is specd to be on for 2 minutes and off for 1. While the other pumps can only be on for 1 minute before they must be rested. This is because the insulation in the coil of the "F" rated pump can take the higher temperatures of the longer duty cycle.
{...}


I also don't know which pump is the best for these machines. Hopefully I won't need to replace mine soon, that's why I didn't make deeper research. :)

walt_in_hawaii

Postby walt_in_hawaii » Jan 12, 2019, 3:39 pm

gaggiaDIY wrote:Thanks! I have been looking at the Invensys pump on eBay. It appears to come close to the original in specs.
The Ulka pump is cheaper/easier to find in The Netherlands. But it's 48W, while the original Eaton pump is 60W. Wouldn't that be a problem, somehow?
What does it mean to have a 2min/1min cycle? In what way is it better? Thanks for your help!


The wattage does not matter, its so small the wiring will accommodate either one. The flow rate is more important. The 2min/1min refers to the duty cycle (time on vs time off). 2 minutes on, 1 minute off to let it cool down, then repeat. If you try to drive these pumps without letting them cool, they will fail.

gaggiaDIY

Postby gaggiaDIY » Jan 12, 2019, 3:43 pm

Thank you both, very interesting!
I suppose then I doesn't really matter which one we'll choose. A cup of espresso never takes more than 1 minute anyway, so both will do, I guess.

myso

Postby myso » replying to gaggiaDIY » Jan 12, 2019, 4:25 pm

Never say never. :)
1min+ shots are business as usual for some.

I have further read that ulka pumps are more reliable and sturdy than invensys pumps. But invensys pumps are easier controllable with a dimmer circuit and they are remarkably more silent.
E4 and E5 both reaches 9 bars at espresso level of flow rates. But E4 might push a bit more pressure on low flowrates so you might need to adjust your opv accordingly. E4 is reported slightly more silent than E5.

On the noise side this order is from loudest to most silent. Ulka E5 - E4 - invensys cp3a - cp4.

http://www.youtube.com/watch?v=5cm8PH6DVjs

Check 0:30s @ 80dB vs 1:36s @ 68dB

gaggiaDIY

Postby gaggiaDIY » Jan 16, 2019, 3:54 pm

Excellent, thanks very much for your detailed reply. I'll give the Invensys pump a try.