# Benefits of HX machines?



## SlingFBarista (Sep 27, 2020)

Hi there,

I recently purchased a Bezzera bz02 and am just about to start servicing it ready for work.

I'm curious to hear from those who've had or have HX machines. What are the pros/cons overall?


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## MediumRoastSteam (Jul 7, 2015)

SlingFBarista said:


> Hi there,
> 
> I recently purchased a Bezzera bz02 and am just about to start servicing it ready for work.
> 
> I'm curious to hear from those who've had or have HX machines. What are the pros/cons overall?


 A simple google search or forum search will land you on a few relevant pages.

Do read about HX vs DB. You'll find the answers. Let us know how you get on and please feel free to ask away more specific questions.

But I'll tell you one each:

pros: simplicity.
cons: cooling flushes.


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## SlingFBarista (Sep 27, 2020)

MediumRoastSteam said:


> A simple google search or forum search will land you on a few relevant pages.
> 
> Do read about HX vs DB. You'll find the answers. Let us know how you get on and please feel free to ask away more specific questions.
> 
> ...


 Thanks for the reply! I understand the basic concepts of HX and DB machines. Am I right in thinking the cooling flushes are akin to temperature surfing on single boiler machines in a way? I know that thermal stability is better in HX machines, but the water at the group head will still drop in temp over the course of a shot right?

I also can't find a whole lot of info on general reliability of HX machines, however they do look awfully simple when opened up, I'm just hoping that is the case!


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## MediumRoastSteam (Jul 7, 2015)

SlingFBarista said:


> Thanks for the reply! I understand the basic concepts of HX and DB machines. Am I right in thinking the cooling flushes are akin to temperature surfing on single boiler machines in a way? I know that thermal stability is better in HX machines, but the water at the group head will still drop in temp over the course of a shot right?
> 
> I also can't find a whole lot of info on general reliability of HX machines, however they do look awfully simple when opened up, I'm just hoping that is the case!


 Yes. You are temp surfing because the water in the HX is superheated as it's at boiler temp, which is around 126C (steaming temp). You then cool it down by removing the water from the HX with fresh water from the tank. The temperature will remain at brew temperature because of the thermal mass of the E61 group head. there's then s recovery time (which is machine dependent). Once you leave it idle for more than 5 minutes - again, some more, some less, depends on the machine - you'll need s cooling flush again.

the exception.... The Lelit MaraX. Google up for reviews. It's a clever HX.


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## SlingFBarista (Sep 27, 2020)

MediumRoastSteam said:


> Yes. You are temp surfing because the water in the HX is superheated as it's at boiler temp, which is around 126C (steaming temp). You then cool it down by removing the water from the HX with fresh water from the tank. The temperature will remain at brew temperature because of the thermal mass of the E61 group head. there's then s recovery time (which is machine dependent). Once you leave it idle for more than 5 minutes - again, some more, some less, depends on the machine - you'll need s cooling flush again.
> 
> the exception.... The Lelit MaraX. Google up for reviews. It's a clever HX.


 Oh okay, well that actually sounds perfect for me. I do about 3-4 shots a day including a couple of milk drinks most days, 2 shots will be pulled back to back and the others an hour or two later. So as long as I'm on it with the cooling flushes and dial in my grind properly, I should theoretically get fairly consistent shots through the day.

Thanks for the info, It'll be the first time I've used a decent machine since I was a barista so fingers crossed! I'll do an update when my setup is up and running.

Thanks again!


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## Norvin (Sep 10, 2014)

I don't think that the BZ02 needs much of a cooling flush, if any. It has a different design to the E61 equipped HX machines.

I suppose that it may depend on the pressurestat setting but I have had three BZ02's and can't remember any needing a flush.


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## SlingFBarista (Sep 27, 2020)

Norvin said:


> I don't think that the BZ02 needs much of a cooling flush, if any. It has a different design to the E61 equipped HX machines.
> 
> I suppose that it may depend on the pressurestat setting but I have had three BZ02's and can't remember any needing a flush.


 How did you find it generally as a machine out of interest? I've actually been wondering about the pressurestat, they seem to cause a bit of grief. Is it one of the more unreliable parts?

Cheers


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## MediumRoastSteam (Jul 7, 2015)

@SlingFBarista - you can find you if you need a cooling flush or not on your machine. Before pulling a shot, flush some water through the group. If the water comes out boiling, steaming, you'll need one. If it doesn't, then you won't need one. Depending on the design, you might even need a warm up flush!

Norvin had a few of them so hopefully will be able to give you some good advice.

good luck!


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## Norvin (Sep 10, 2014)

I liked the Bezzeras. They are very well built, you get a lot of bang per buck in buying one. They have the same internals as some more expensive machines so problem areas tend to be the same as all old machines - items in the control box failing, pressurestats, pumps etc. Usually cheap to replace. The heating element power is switched by a relay, taking load off the control box relay and pressurestat points which is better than on the ECM have been working on recently.

The pressurestat is the usual MA-TER found on loads of machines. Quite cheap (about £15) to replace but you may have trouble adjustng it as there is no gauge to check the steam pressure. Someone is selling a chinese stat for about £13 on ebay that he says is factory adjusted to 1 bar, that may help but I would not replace it unless you were having problems.

If you are buying that machine from the seller in Sheffield I would still check that it is a ground coffee machine. It was originally listed as a pod machine. It is not unknown for someone to use a portaflter with a ground coffee basket in a pod machine. Check the underside of the group bell to see if there is a screen and dispersion disc, I posted a picture of the two types side by side once so it may be worth searching, I can probably find it again if it has disappeared. I contacted the seller about buying it when I was there for a weekend recently but she finally answered after I had left.

I would clean and descale it, replace group gasket and use it, let the taste guide you as to whether it needs a coolng flush.


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## SlingFBarista (Sep 27, 2020)

Norvin said:


> I liked the Bezzeras. They are very well built, you get a lot of bang per buck in buying one. They have the same internals as some more expensive machines so problem areas tend to be the same as all old machines - items in the control box failing, pressurestats, pumps etc. Usually cheap to replace. The heating element power is switched by a relay, taking load off the control box relay and pressurestat points which is better than on the ECM have been working on recently.
> 
> The pressurestat is the usual MA-TER found on loads of machines. Quite cheap (about £15) to replace but you may have trouble adjustng it as there is no gauge to check the steam pressure. Someone is selling a chinese stat for about £13 on ebay that he says is factory adjusted to 1 bar, that may help but I would not replace it unless you were having problems.
> 
> ...


 Wow thanks for all the information there, I really appreciate it. I'll bare the eBay pressurestat in mind for the future and follow your advice on the initial setup. I'm sure I'll be doing another post soon about the machine so I may have to pick your brain again in the near future!


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## MediumRoastSteam (Jul 7, 2015)

Norvin said:


> The pressurestat is the usual MA-TER found on loads of machines. Quite cheap (about £15) to replace but you may have trouble adjustng it as there is no gauge to check the steam pressure.


 @SlingFBarista - ther should not be a problem! You can mount a pressure gauge temporarily on the steam wand - that's exactly how I adjusted the pstat on my La Pavoni. All you need is a silicone hose and an el cheapo gauge from eBay. 👍

Like here:

https://www.coffeeforums.co.uk/topic/41198-la-pav/?do=embed&comment=598236&embedComment=598236&embedDo=findComment


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## SlingFBarista (Sep 27, 2020)

MediumRoastSteam said:


> @SlingFBarista - ther should not be s problem! You can mount a pressure gauge temporarily on the steam wand - that's exactly how I adjusted the pstat on my La Pavoni. All you need is a silicone hose and an el cheapo gauge from eBay. 👍
> 
> Like here:
> 
> https://www.coffeeforums.co.uk/topic/41198-la-pav/?do=embed&comment=598236&embedComment=598236&embedDo=findComment


 Even better! I'm kind of hoping the pressurestat will need replacing before anything else now...


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## SlingFBarista (Sep 27, 2020)

Norvin said:


> I would clean and descale it, replace group gasket


 Do you know where I can get gaskets and seals from by any chance?


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## Norvin (Sep 10, 2014)

The group gasket is a common 73x57x8mm and can be found on ebay. I can't help much with seal suppliers, If i need any I usually measure them and buy from O ring suppliers on ebay.


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## SlingFBarista (Sep 27, 2020)

Norvin said:


> The group gasket is a common 73x57x8mm and can be found on ebay. I can't help much with seal suppliers, If i need any I usually measure them and buy from O ring suppliers on ebay.


 Cheers, much appreciated


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