Anyone? Anyone?

 

Brady?

 

Anyone?

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That's a great point, Mike. What you've described is probably pretty straightforward field conversion too - maybe an hour's worth of work plus 50-100 bucks worth of parts?

 

I hadn't realized that the SIS chamber was plugged on that version... do you feel like that's an essential part of the conversion?

 

Thanks for sharing. Theorizing is nice, but there's no substitute for actual experience.


Mike Sabol said:

Just to split a few more hairs, the PID is not the only difference between the WBC and stock model Aurelias.  The jets I mentioned earlier are also different, as well as, there being a plug in the preinfusion chamber.  The jets are quite a bit smaller than on the stock machine, which really slows down how fast the water moves through the group head.  Both in the thermosyphon cycle and when trying to pull a shot.  Simply changing these parts will make your stock Aurelia behave quite differently.  It even sounds different.  And the espresso is quite different as well.  I think it's a little sweeter and the texture is lighter.  I've switched a couple of stock Aurelias over to this WBC jetting with out adding the PID and have achieved great results.

 

Brady, your point that the PID will make the system more stable, I agree with.  But to reiterate my earlier point the jetting in the flowmeters and groupheads on the Aurelia actually have a bigger effect on the coffee than PID does.  And it would be hard to tell, without talking to Ben at NS, about which part of that system allowed the Aurelia to pass WBC muster.  They are probably both interdependent although I would imagine that the PID was necessary to allow tighter control of the highly restricted hx.

 

Brady said:

True, the temperature control on the Digit is by pressure transducer, not thermocouple. However, with the relationship between pressure and temperature being direct, do you feel like that distinction is relevant? If you think about it, even electronic "temperature" control using a thermocouple relies on the direct relationship between temperature and sensor electrical resistance... maybe I'm splitting hairs.

 

The point I was attempting to make was that there was benefit to electronic boiler temperature control on an hx machine... hence its use on the Competizione model to enable it to meet the WBC spec. The fact that this machine meets WBC spec and the standard model doesn't kind of makes that point, doesn't it?

 

Also, I wouldn't say that this approach changes the fact that this is a hx machine - it just makes it more predictable. As a friend of mine once said, all they've done is make a hx that actually works properly. To suggest that improving temperature control on an hx machine is making an apple into an orange is kind of silly - especially considering how many DB machines don't use PID, and how many stock HX machines use temperature transducers.

 

You are correct, too, that it would be difficult to directly control brew water temp on a hx machine... impossible on a multiple-group machine. So you definitely need to understand the limitations of the configuration. That doesn't mean you can't make your brew water temperature stable though.


Troy L Mallett said:

Brady, the newest Aurelias use a PID to control boiler pressure electronically, and not the temperature directly. Even at that, the controls step at intervals of 0.05.

 

I have been working on putting a PID into my appia, but there are much more significant problems than just replacing the pressostat with a PID. Each measure completely different things. The pressostat manages the pressure in the boiler, thus the brew water temp indirectly). A DB machine with a PID regulates the temperature of brew water (in the brew boiler) by adjusting the on/off cycle of the heating element. The two things that you will have to overcome if you are to consider putting in a PID is how to quickly adjust the water temperature inside the HX without creating too many problems with steam generation, and where you will put the thermometer probe that will work the PID.

 

I think that you might want to invest in a more sensitive P-stat (or maybe an electronically controlled one vis WBC aurelia) or maybe get a DB system if you are bent on PID. While it might be neat to have an orange coloured apple, maybe it is better to leave apples and oranges apart.

Yeah, the changing of the jets is actually pretty simple.  Provided, of course, the machine isn't hammered.  Getting into the fittings on the group head and on the bottom of the hX can either be easy or cause great swearing and shed blood.  As you know.

 

The plug isn't the key but it's necessary.  The key are the tiny jets on the inlet of the hX and the top of the group head.  But they slow down the flow so much that the preinfusion chamber is too big so the plug just soaks up some space to allow the correct amount of preinfusion time and pressure ramp up.

 

This kind of mod is actually way easier and requires less monkeying around than the PID retrofit.  If it's done by someone who's had an Aurelia apart before it can be done in 30-40 minutes.  Even less if there is a convenient way nearby for draining the exchangers and the fittings aren't too difficult.


Brady said:

That's a great point, Mike. What you've described is probably pretty straightforward field conversion too - maybe an hour's worth of work plus 50-100 bucks worth of parts?

 

I hadn't realized that the SIS chamber was plugged on that version... do you feel like that's an essential part of the conversion?

 

Thanks for sharing. Theorizing is nice, but there's no substitute for actual experience.


Mike Sabol said:

Just to split a few more hairs, the PID is not the only difference between the WBC and stock model Aurelias.  The jets I mentioned earlier are also different, as well as, there being a plug in the preinfusion chamber.  The jets are quite a bit smaller than on the stock machine, which really slows down how fast the water moves through the group head.  Both in the thermosyphon cycle and when trying to pull a shot.  Simply changing these parts will make your stock Aurelia behave quite differently.  It even sounds different.  And the espresso is quite different as well.  I think it's a little sweeter and the texture is lighter.  I've switched a couple of stock Aurelias over to this WBC jetting with out adding the PID and have achieved great results.

 

Brady, your point that the PID will make the system more stable, I agree with.  But to reiterate my earlier point the jetting in the flowmeters and groupheads on the Aurelia actually have a bigger effect on the coffee than PID does.  And it would be hard to tell, without talking to Ben at NS, about which part of that system allowed the Aurelia to pass WBC muster.  They are probably both interdependent although I would imagine that the PID was necessary to allow tighter control of the highly restricted hx.

 

Brady said:

True, the temperature control on the Digit is by pressure transducer, not thermocouple. However, with the relationship between pressure and temperature being direct, do you feel like that distinction is relevant? If you think about it, even electronic "temperature" control using a thermocouple relies on the direct relationship between temperature and sensor electrical resistance... maybe I'm splitting hairs.

 

The point I was attempting to make was that there was benefit to electronic boiler temperature control on an hx machine... hence its use on the Competizione model to enable it to meet the WBC spec. The fact that this machine meets WBC spec and the standard model doesn't kind of makes that point, doesn't it?

 

Also, I wouldn't say that this approach changes the fact that this is a hx machine - it just makes it more predictable. As a friend of mine once said, all they've done is make a hx that actually works properly. To suggest that improving temperature control on an hx machine is making an apple into an orange is kind of silly - especially considering how many DB machines don't use PID, and how many stock HX machines use temperature transducers.

 

You are correct, too, that it would be difficult to directly control brew water temp on a hx machine... impossible on a multiple-group machine. So you definitely need to understand the limitations of the configuration. That doesn't mean you can't make your brew water temperature stable though.


Troy L Mallett said:

Brady, the newest Aurelias use a PID to control boiler pressure electronically, and not the temperature directly. Even at that, the controls step at intervals of 0.05.

 

I have been working on putting a PID into my appia, but there are much more significant problems than just replacing the pressostat with a PID. Each measure completely different things. The pressostat manages the pressure in the boiler, thus the brew water temp indirectly). A DB machine with a PID regulates the temperature of brew water (in the brew boiler) by adjusting the on/off cycle of the heating element. The two things that you will have to overcome if you are to consider putting in a PID is how to quickly adjust the water temperature inside the HX without creating too many problems with steam generation, and where you will put the thermometer probe that will work the PID.

 

I think that you might want to invest in a more sensitive P-stat (or maybe an electronically controlled one vis WBC aurelia) or maybe get a DB system if you are bent on PID. While it might be neat to have an orange coloured apple, maybe it is better to leave apples and oranges apart.

Mike (and, by extension, Brady too), 

 

This is incredibly useful info. And I do want my espresso to be sweeter and lighter!

 

So, the question is this: If I was going to have my tech do this, what parts would I need to have him order, and what do I tell him to do with them? Unless, of course, one of you guys is planning on being in the Bowling Green, Ky., area anyway and wants some extra work. :-)

Hey Mike... you ought to kit it :).

 

I wonder how RJ's tech would feel about him buying those parts from you?

I can get part numbers but I'm not set up with NS yet, at least, not for my new company, so I can't order the parts.  I'll put the list together and post it.  The tech in KY should be able to order the parts.  I'd be happy to consult over the phone, as well.  No charge.  If the tech knows what he/she is doing I'll be on the phone with them for 3 or 4 minutes.  It's very straight forward, except for reality.  The only caveat I will offer is that once you start getting into some of those fittings you risk everything that that kind of operation entails. I cannot guarantee a smooth and painfree experience.  I will assume that the machine is in pretty good shape and has been using correctly treated/filtered water.  So things should be OK.  Should be.  You just don't know for sure until you know for sure.

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