# Gaggia Classic Pump Replacement - Invensys



## Khashy

Hello guys and gals,

I have not done anything to my Classic in a while and am itching to do a mod to curb the current upgraditis urges.

I liked the whole dimmer thing that I have done a few people do in the forum and I understand that the pump should be replaced for that.

I know @MrShades recommends the Invensys 65W CP3A pump but since Invensys are no more, I'm not certain which one of the results that comes back on fleebay is the correct pump.

(http://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.Xcp3a.TRS0&_nkw=cp3a&_sacat=0)

Any ideas?

Thanks.


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## Khashy

I decided to take the plunge and got this one in the end:

http://www.ebay.co.uk/itm/CP3A-Pump-65W-230V-Gaggia-Classic-Coffee-Machine-Maker-Invensys-Eaton-Williams-L-/400700320088?hash=item5d4b99a958:g:ryoAAOSwg3FUfEqR

I'll update this post if it turns out to be the correct one.


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## MrShades

Yes, you should be OK with that one @Khashy - it's an Invensys CP3A, which is what you need.


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## jimbojohn55

looks like the right one on specs - do us a side by side pic when you swop them for reference - cheers


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## Khashy

thanks @MrShades.

@jimbojohn55 will post the side by side as soon as it arrives.

I'm also ordering this guy to do my pressure profiling (fingers crossed for that one):

https://www.amazon.co.uk/gp/product/B005ERPJA0/ref=ox_sc_act_title_2?ie=UTF8&psc=1&smid=A24H25OE38LW9I


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## MrShades

Are you fitting a pressure gauge? Without one you're wiggling your dimmer switch in the dark... so to speak.


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## Asgross

Make sure you have been sent

"65w cp3a"

I bought off fleabay the '65w CP3A" but after fitting it , it seemed to take a long time to reach full output / pressure -

Eventually took it out and found onside of pump I'd been actually sent

65w cp3B -looks the same !

The seller said both models are identical, and refused a refund but they aren't as I found correct model off another seller and this worked fine.

Keep meaning to complain to fleabay

But good luck with this mod

I keep meaning to Finnish mine with it and the fitted pressure gauge


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## Khashy

MrShades said:


> Are you fitting a pressure gauge? Without one you're wiggling your dimmer switch in the dark... so to speak.


I figured I'd use my pressure gauge portafilter and mark the various pressures on the dimmer. My theory was that say marker 1 on the dimmer will correspond to 1 bar etc.

do you think that won't work?


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## Khashy

Asgross said:


> Make sure you have been sent
> 
> "65w cp3a"
> 
> I bought off fleabay the '65w CP3A" but after fitting it , it seemed to take a long time to reach full output / pressure -
> 
> Eventually took it out and found onside of pump I'd been actually sent
> 
> 65w cp3B -looks the same !
> 
> The seller said both models are identical, and refused a refund but they aren't as I found correct model off another seller and this worked fine.
> 
> Keep meaning to complain to fleabay
> 
> But good luck with this mod
> 
> I keep meaning to Finnish mine with it and the fitted pressure gauge


oh god, please no!

Okay fingers crossed. Thanks for the heads up


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## MSM

Also thinking about doing this.

Please let me know Khashy once it arrives!


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## Khashy

MSM said:


> Also thinking about doing this.
> 
> Please let me know Khashy once it arrives!


Will do.


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## Khashy

Sorry it took a long time to respond to this, I have been traveling and just got the chance to get to the coffee machine.

So as @*Asgross* had suspected, I did in fact receive the CP3B, rather than the CP3A as it was advertised - will get on to complaining to the seller for this.

I did go ahead and replace it per @*MrShades* instructions from another thread - thanks for that.

I haven't really had a chance to test it out properly, so it might work.

I also fitted the dimmer while I was at it. Seems to work, I am yet to try out the different pressures I get from moving the dimer up and down.

Looking forward to playing around with 'pressure profiling'.


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## Khashy

Here are the side by side pump photos for reference.









sorry about the orientation on some of these


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## Asgross

Khashy said:


> Sorry it took a long time to respond to this, I have been traveling and just got the chance to get to the coffee machine.
> 
> So as @*Asgross* had suspected, I did in fact receive the CP3B, rather than the CP3A as it was advertised - will get on to complaining to the seller for this.
> 
> I did go ahead and replace it per @*MrShades* instructions from another thread - thanks for that.
> 
> I haven't really had a chance to test it out properly, so it might work.
> 
> I also fitted the dimmer while I was at it. Seems to work, I am yet to try out the different pressures I get from moving the dimer up and down.
> 
> Looking forward to playing around with 'pressure profiling'.


I'm really looking toward to seeing your results


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## Khashy

Right, doing some more research on CP3A vs CP3B, I'm sad to report that CP3B is inferior to CP3A:

CP3A:

http://www.aet-us.com/FCKeditor/UserFiles/File/CP03A-120V.pdf

CP3B:

http://www.aet-us.com/FCKeditor/UserFiles/File/CP3BSP_ST-120V.pdf

As you can see, CP3A has a higher flow rate and also a thermostat which CP3B does not.

I have requested a refund from the ebay seller.

I'll see what effect this has on the coffee being produced, I have a feeling I'll have to re-order the correct pump (if I can find it) an do the pump replacement again.

@*Asgross* what did you end up buying in the end? happen to have a link?

Thanks,

K.


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## Asgross

Khashy said:


> Right, doing some more research on CP3A vs CP3B, I'm sad to report that CP3B is inferior to CP3A:
> 
> CP3A:
> 
> http://www.aet-us.com/FCKeditor/UserFiles/File/CP03A-120V.pdf
> 
> CP3B:
> 
> http://www.aet-us.com/FCKeditor/UserFiles/File/CP3BSP_ST-120V.pdf
> 
> As you can see, CP3A has a higher flow rate and also a thermostat which CP3B does not.
> 
> I have requested a refund from the ebay seller.
> 
> I'll see what effect this has on the coffee being produced, I have a feeling I'll have to re-order the correct pump (if I can find it) an do the pump replacement again.
> 
> @*Asgross* what did you end up buying in the end? happen to have a link?
> 
> Thanks,
> 
> K.


Hi

Try this :-

https://www.ebay.co.uk/itm/130832565996

GAGGIA 187721758 65W CP3A VIBRATORY WATER PUMP FOR COFFEE MAKER ESPRESSO MACHINE

I'm not 100%

So maybe send a query before buying ?

Alan


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## Khashy

Asgross said:


> Hi
> 
> Try this :-
> 
> https://www.ebay.co.uk/itm/130832565996
> 
> GAGGIA 187721758 65W CP3A VIBRATORY WATER PUMP FOR COFFEE MAKER ESPRESSO MACHINE
> 
> I'm not 100%
> 
> So maybe send a query before buying ?
> 
> Alan


Thanks, at least it says CP3A on the pump in the photo.

I was thinking of getting the CP4ASP:

http://www.aet-us.com/FCKeditor/UserFiles/File/CP4SP.pdf

It's more expensive but it's advertised as 'top quality' as opposed to the CP3A which is advertised as 'srandard'

anyone tried this? Is it worth the price difference?

Thanks.

k.


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## Khashy

Right, quick report back;

I am returning the CP3B pump. Have already ordered the CP4SP, figured I'd take a chance with it.

in the meantime, I did one experiment with varying the pressure profile:

6 seconds of pre-infusion (2bars of pressure), followed by ramping up to full in 3 seconds and then slowly down to about 6 bars until I was about 3 grams off my weight target, then ramp the pressure down to zero over 2 seconds.

That was the plan, I tried my best to follow as closely as possible but I'm sure I wasn't spot on. I ended up overshooting the weight and ended up with 38g in the cup from an 18g dose.

The taste was definitely different to my normal shots. Better in someways in that there was next to no undesired sourness. I would say the coffee was a bit over extracted but not unpleasant.

The other noticeable thing I would point out was the fact that the shot felt thin. Less body I guess or kind of watery for the lack of a better term. I'm splitting hair here but I would have liked it a bit more body. I suspect this may have been a result of the overshoot of the extraction volume.

I took inspiration from these charts, trying to replicate the LM lever profile.


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## Asgross

Khashy said:


> Right, quick report back;
> 
> I am returning the CP3B pump. Have already ordered the CP4SP, figured I'd take a chance with it.
> 
> in the meantime, I did one experiment with varying the pressure profile:
> 
> 6 seconds of pre-infusion (2bars of pressure), followed by ramping up to full in 3 seconds and then slowly down to about 6 bars until I was about 3 grams off my weight target, then ramp the pressure down to zero over 2 seconds.
> 
> That was the plan, I tried my best to follow as closely as possible but I'm sure I wasn't spot on. I ended up overshooting the weight and ended up with 38g in the cup from an 18g dose.
> 
> The taste was definitely different to my normal shots. Better in someways in that there was next to no undesired sourness. I would say the coffee was a bit over extracted but not unpleasant.
> 
> The other noticeable thing I would point out was the fact that the shot felt thin. Less body I guess or kind of watery for the lack of a better term. I'm splitting hair here but I would have liked it a bit more body. I suspect this may have been a result of the overshoot of the extraction volume.
> 
> I took inspiration from these charts, trying to replicate the LM lever profile.
> 
> View attachment 23605


How much was the superior pump and where did you find it ?

How do you know the pressure during the course of the extraction ?

Have you fitted a pressure gauge to the gaggia ?


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## Khashy

Asgross said:


> How much was the superior pump and where did you find it ?
> 
> How do you know the pressure during the course of the extraction ?
> 
> Have you fitted a pressure gauge to the gaggia ?


The pump is being shipped from Germany, found it on fleebay:

http://pages.ebay.com/link/?nav=item.view&alt=web&id=321769453659

worked out to £22 including postage.

I don't have an inline pressure guage, yet, as I'm too scared to drill the hole in the body.

I took the static pressure with my pressure guage'd portafilter, subtracted 1 bar from it and marked the position on the dimmer slider.

Kind of an educated guess, but it's the best I could think of without a proper way of measuring pressure.


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## AndyZap

@Khashy - how do you like the pump? I decided to give it a go as well, and just ordered the one from Germany, your link still works fine http://pages.ebay.com/link/?nav=item...d=321769453659


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## MSM

Still on the fence, might try doing this along with dimmer but would want to add the pressure gauge which seems a lot of work.


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## MrShades

MSM said:


> Still on the fence, might try doing this along with dimmer but would want to add the pressure gauge which seems a lot of work.


The pressure gauge is easy - simple fitting and works very well.

The bloody tough part is cutting a hole in the front of the case - and making sure it's in the right place!

If you wanted to make it easier then you could always fit a gauge and mount it in an external box (you may have some fun finding a way to get the capillary tube routed out of the case - but cutting vents out at the back with a hacksaw would probably be relatively simple).


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## mcrmfc

A tip if you are going down the hole saw route...you can get away with a cheap hole saw. I used this one:

Wolfcraft 5469000 40mm Hole Saw Bim Complete with Hexagon Adapter and Centring Drill https://www.amazon.co.uk/dp/B001W7AW6W/ref=cm_sw_r_cp_apa_zHFhzb3RQ0773

But you MUST get the best HSS drill bit you can for the pilot hole. The one that comes with the hole saw won't be good enough.

Start with a really small size pilot hole and progressively increase. Then your hole saw bit will go through just fine and the saw itself will be like a knife through butter...well more or less!


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## MSM

Thanks, been talked into it! hehe

Could someone let me know a good T connector to buy?


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## mcrmfc

MSM said:


> Thanks, been talked into it! hehe
> 
> Could someone let me know a good T connector to buy?


It's something like this...

http://r.ebay.com/sNb1tX

Ignore the first link i put...it needs to be the male version!!!

I think it's the 6mm push-fit and 1/8 BSP male screw you need.


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## MSM

Thanks, bought the connector and will try drilling the hole for the pressure gauge tonight. Pump has been replaced with a ARS CP3A and tested - works fine









Will next look for a dimmer!

*CP3A **CP3A *


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## Michael87

Did anyone find a good dimmer?

Would something like this work?

https://www.electricaldirect.co.uk/product/hamilton-hartland-100w-1-gang-2-way-led-dimmer-switch-satin-chrome-674438?vat=1&shopping=true&gclid=Cj0KCQiA0ZHwBRCRARIsAK0Tr-rsrc7iv7SyqN5xbGit9CjCdtzOHSbdP2eyBkODNv-UTW95UCTmC6UaApLUEALw_wcB&gclsrc=aw.ds

It is a 100W dimmer for a light. If the pump is 65W, I think that should be ok?


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## Asgross

I used a dimmer switch from Amazon that was meant for a floor standing lamp - so fully enclosed.
It worked perfectly.

Sent from my iPhone using Tapatalk


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## Michael87

Asgross said:


> I used a dimmer switch from Amazon that was meant for a floor standing lamp - so fully enclosed.
> It worked perfectly.
> 
> Sent from my iPhone using Tapatalk


 Thanks. Did you mount it to the machine?

I am having a headache finding something that can be fitted onto the side. I thought a chrome dimmer light switch with plate might work but could look quite ugly unless I can find a very slim one....


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## Asgross

Theres no getting around it- its not attractive.
My dimmer was black plastic, i used double sided sticky tape.

But this dimmer mod + mr shades excellent pid, and a decent grinder; (i was using a OE pharos), can produce truly great tasting coffee.

Sent from my iPhone using Tapatalk


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## light87

Hi

I have just opened a thread about this, anyway I'm looking for information about pump replacement in the gaggia baby, have everyone use the 70W pump from fluid-o-tech ? It cost much more than the usual but seem better.

There even is one from OLAB.


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## jpd99

Khashy said:


> Right, doing some more research on CP3A vs CP3B, I'm sad to report that CP3B is inferior to CP3A:
> 
> CP3A:
> 
> http://www.aet-us.com/FCKeditor/UserFiles/File/CP03A-120V.pdf
> 
> CP3B:
> 
> http://www.aet-us.com/FCKeditor/UserFiles/File/CP3BSP_ST-120V.pdf
> 
> As you can see, CP3A has a higher flow rate and also a thermostat which CP3B does not.
> 
> I have requested a refund from the ebay seller.
> 
> I'll see what effect this has on the coffee being produced, I have a feeling I'll have to re-order the correct pump (if I can find it) an do the pump replacement again.
> 
> @*Asgross* what did you end up buying in the end? happen to have a link?
> 
> Thanks,
> 
> K.


 @Khashy - did you ever get your refund on the wrong pump in the end? Keen to do the same thing, but currently struggling a bit with this same vendor!


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## Anton Vowel

Hi

I have an old-style Classic.

I've just bought an ARS CP.3A.381.0/ST pump as (I think!) the original needs replacing.

I've ordered some PFTE tape to seal the connection threads.

I watched a replacement video of a similar pump on Youtube and saw that they exchanged a fuse wire that went from the pumo to one of the front switches. Can anyone tell me if this is something I need to buy and fit?

Is there a good link to detailed instructions? Someone has mentioned @mrshades has put this somewhere but I can't find it.

Thanks


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## Khashy

jpd99 said:


> @Khashy - did you ever get your refund on the wrong pump in the end? Keen to do the same thing, but currently struggling a bit with this same vendor!


 I realise this reply is a few months too late, but no, I don't think I got a refund tbh


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## light87

I have an old Eaton pump on my Gaggia Classic and I was considering replacing it with an ULKA EX5GW that should have better flow rate / pressure diagrams, is there anyone who already did this and can tell if there is a quality difference between them? I already have the pressure gauge installed and of course I have set the pressere of the OPV to 9 bar.


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## Sharkie

@MrShadesmay be able to help


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## light87

Assuming that these diagrams are true, this is the characteristic curve of the ulka pump:









The blue curve for the E5 model is the one of our interest and so for 9 bar it grants about 250 cm^3 / min of water flow rate.

Instead this is the characteristic curve of the Invensys ARS pump which if I have understood well is the same of my Eaton pump:









And so the flow rate is about 200 cm^3/min at 9 bar pressure so there is a little less water flow.

So the ulka pump is a little better regaring performance but the question of course is: this is appreciable ?


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## MrShades

light87 said:


> Assuming that these diagrams are true, this is the characteristic curve of the ulka pump:
> 
> View attachment 62155
> 
> 
> The blue curve for the E5 model is the one of our interest and so for 9 bar it grants about 250 cm^3 / min of water flow rate.
> 
> Instead this is the characteristic curve of the Invensys ARS pump which if I have understood well is the same of my Eaton pump:
> 
> View attachment 62157
> 
> 
> And so the flow rate is about 200 cm^3/min at 9 bar pressure so there is a little less water flow.
> 
> So the ulka pump is a little better regaring performance but the question of course is: this is appreciable ?


 You only need a flow of about 60ml in 30s, so 120 cm3/min to make an espresso - so it'll make little if any difference at all


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## light87

I see.

Regarding the installation instead? Is that possible to install the Ulka pump on the rubber silent block of the eaton pump? The diameter of the plastic termination in the ulka is minor than the one on the eaton..have you ever done this?


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## MrShades

light87 said:


> I see.
> 
> Regarding the installation instead? Is that possible to install the Ulka pump on the rubber silent block of the eaton pump? The diameter of the plastic termination in the ulka is minor than the one on the eaton..have you ever done this?


 That should be ok, yes.


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## light87

The fact is that newer Classic pro comes with Ulka pump already installed but they use rigid bracket to hold the pump, my old classic with the eaton pump has the rubber silent block to hold it, also the Rubber cushion has a larger hole to fit the sliglhy larger inlet shaft of the eaton pump so I don't know if with the ulka the pump would start moving too much because it doesn't have the rigid bracket and it's just inserted on the rubber silent block.

Is there someone who has already put the ulka on top of the rubber silent block?


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