[DavecUK]

The hose I marked is entering the pump, the other one leaving the pump would be at 9 bar+ pressure!! probably most of the expansion valve discharge will enter the pump causing very little to go back to the tank, or none.

I can't help you with the diagram because events have overtaken me at the moment and this roaster review needs doing. I requested some software changes to the MaraX, so will be opening mine up to replace the control box soon (waiting for it to arrive from Italy) and will take some detailed photos of it then. Before I install the control box, I want to see if I can read the code off it and work out how to reflash existing boxes.

 

[MediumRoastSteam]

Fantastic, thank you so much!

Finally, can you help identify which of the 4 hoses connected to the X is the OPV discharge?

View attachment 47682

@Doram - this is the OPV, and the hose connected to it is pointed with an arrow, at the top. Just follow that hose.

 

[Doram]

Huge thanks @DavecUKand @MediumRoastSteam, this is all extremely helpful!

I just hope other interested Mara X owners will be able to find this golden information hiding here, lol.

 

[kico]

Thanks for sharing this all!

Do you know how much water will be saved per shot? After I pull a shot the OPV valve shoots out old coffee coloured water. This isn't the water being re-routed? What water is being re-routed?

Does this mean there is very little point in doing this?

I don't really worry much about excess water since I have an RO system plumed in but it would make me feel better if there was a significant enough reduction of any excess waste.

The hose I marked is entering the pump, the other one leaving the pump would be at 9 bar+ pressure!! probably most of the expansion valve discharge will enter the pump causing very little to go back to the tank, or none.

I can't help you with the diagram because events have overtaken me at the moment and this roaster review needs doing. I requested some software changes to the MaraX, so will be opening mine up to replace the control box soon (waiting for it to arrive from Italy) and will take some detailed photos of it then. Before I install the control box, I want to see if I can read the code off it and work out how to reflash existing boxes.

Which software changes did you request?

 

[Doram]

Do you know how much water will be saved per shot? After I pull a shot the OPV valve shoots out old coffee coloured water. This isn't the water being re-routed? What water is being re-routed?

Does this mean there is very little point in doing this?

The water that can be reused is the excess water the pump pushes over the 9-11 bars that goes into the coffee, I think. If I remember correctly, the pump pushes 15 bars, so the difference is discharged and can be re-routed and re-used. It's not the dirty water you get from the bottom of the group after pulling a shot, lol.

How much will be saved and is this worth doing? Good questions! (I think Dave said not much, 20-30ml per shot maybe?). Anyone knows for sure?

 

[kico]

The water that can be reused is the excess water the pump pushes over the 9-11 bars that goes into the coffee, I think. If I remember correctly, the pump pushes 15 bars, so the difference is discharged and can be re-routed and re-used. It's not the dirty water you get from the bottom of the group after pulling a shot, lol.

How much will be saved and is this worth doing? Good questions! (I think Dave said not much, 20-30ml per shot maybe?). Anyone knows for sure?

I'm pretty certain they re-route the dirty water at costa / starbucks as it makes no difference on their end result. If anything, it adds more of a fuller burnt flavour 😂

40-60ml saved for a double shot doesn't actually seem like much but I may consider it.
It would certainly recommend getting a RO filter plumed in if you can! Seems cheaper than the other RO option suggested on here.

 

[disq]

I measured it right after I did the mod about two weeks ago, according to my records back then, 85ml of water was reclaimed in my 38.6g (~49 seconds) shot.

 

[kico]

I measured it right after I did the mod about two weeks ago, according to my records back then, 85ml of water was reclaimed in my 38.6g (~49 seconds) shot.

That is a reasonable amount!

Why on earth wouldn't Lelit do this as standard with the MaraX? With the whole save the planet push going on...

I'm guessing doing this = kissing my warranty bye bye?

If that's the case I'll wait 18 months or so.

 

[Doram]

I'm pretty certain they re-route the dirty water at costa / starbucks as it makes no difference on their end result. If anything, it adds more of a fuller burnt flavour 😂

lol, I'm sure it contributes to a very special flavour profile.

40-60ml saved for a double shot doesn't actually seem like much but I may consider it.
It would certainly recommend getting a RO filter plumed in if you can! Seems cheaper than the other RO option suggested on here.

I measured it right after I did the mod about two weeks ago, according to my records back then, 85ml of water was reclaimed in my 38.6g (~49 seconds) shot.

Might not sound much, but it seems more than the water that goes into the coffee. I use bottled water (for now), so might be more significant for me. In addition, saving water is only one aspect of the mod. The second is that less water goes into the tray, so less emptying needed - again small but nice improvement.
wouldn't go crazy over this issue, but the mod sounds like a very easy and simple thing to do, so I will probably try to do it.

 

[disq]

Might not sound much, but it seems more than the water that goes into the coffee. I use bottled water (for now), so might be more significant for me. In addition, saving water is only one aspect of the mod. The second is that less water goes into the tray, so less emptying needed - again small but nice improvement.
wouldn't go crazy over this issue, but the mod sounds like a very easy and simple thing to do, so I will probably try to do it.

Exactly, it's a lot and it's noticably fewer refills in the tank as well as fewer emptying of the drip tray. (edit: less vs fewer)

 

[MediumRoastSteam]

That is a reasonable amount!

Why on earth wouldn't Lelit do this as standard with the MaraX? With the whole save the planet push going on...

I'm guessing doing this = kissing my warranty bye bye?

If that's the case I'll wait 18 months or so.

A reversible option, and non-destructive would be, if you have space under the machine, is to route the hose not back to the tank, but underneath the machine and that going into a bottle that you can then tip it back into the tank at the end of the day for example - if water saving is important to you. It is for me, because I distil and remineralise my water, and, it takes me 6 hours to distil 3 litres... Price wise, it works out the same than buying bottled water, but at least I know I am not contributing to landfill AND know exactly what goes inside my water. 🙂

 

[kico]

Certainly does make sense!

Would it affect the warranty?

My marax is about 15cm from the sink and I always rinse out the drip tray at the end of the day. I also have a long tube extended RO tap so I don't even need to take the water tank out to refill it (takes about 20 seconds).

 

[MediumRoastSteam]

Certainly does make sense!

Would it affect the warranty?

My marax is about 15cm from the sink and I always rinse out the drip tray at the end of the day. I also have a long tube extended RO tap so I don't even need to take the water tank out to refill it (takes about 20 seconds).

It would affect warranty, of course. But if you can revert it without leaving any traces, should you need to make a claim...

 

[kico]

A reversible option, and non-destructive would be, if you have space under the machine, is to route the hose not back to the tank, but underneath the machine and that going into a bottle that you can then tip it back into the tank at the end of the day for example - if water saving is important to you. It is for me, because I distil and remineralise my water, and, it takes me 6 hours to distil 3 litres... Price wise, it works out the same than buying bottled water, but at least I know I am not contributing to landfill AND know exactly what goes inside my water. 🙂

The water bottle idea is great!

 

[disq]

Ever noticed the subtle "leak" into the drip tray when you're pulling a shot with the Mara X? That's mostly(?) caused by the OPV (over pressure valve) regulating water pressure by wasting it through the drip tray, leading to frequent filling of the tray and wasting precious (and sometimes expensive) unused water. It's possible to reroute it back to the water tank (or to an external receptacle of sorts) with just minor (possibly warranty voiding?) modification.

This was recently talked about in the thread below, but it would be best to get a specific thread going for this.

https://www.coffeeforums.co.uk/topic/55360-my-marax-warm-up-time-findings/?do=embed

How much water does it save?

I measured it right after I did the mod about two weeks ago, according to my records back then, 85ml of water was reclaimed in my 38.6g (~49 seconds) shot.

What do I need?

A 6mm Y-connector, brass one is recommended in this post but I've used this plastic one, I'm going to replace it later.

Here's the gist of it. You start with this junction here:

These three hoses are all connected to each other and they discharge into the drip tray using the fourth one. It's simply a matter of replacing this connector with a 3-way (Y-connector) thereby eliminating the OPV discharge hose from the connection. Then it looks like this (I replaced it with a plastic Y-connector, but I'm told brass would be better and more durable)

And you're left with this, to do with how you please:

The obvious solution is the reroute it (the hose is long enough) back into the water tank, but if you don't trim some of the water tank housing (careful, you don't want to crack it) it's not possible to close the cover completely. Anyway once you trim the edge it looks something like this:

Of course if you take the tank out to fill it, you now have this hose to deal with. But water in the tank will last longer, and you'll need to empy the drip tray less frequently.

 

[disq]

Just posted a new thread here about the discharge mod:

https://www.coffeeforums.co.uk/topic/55705-mara-x-opv-discharge-rerouting/?do=embed

 

[kico]

How did you make a smooth cut in the plastic water tank?

Sorry - my diy goes as far as a pair of scissors / screwdriver set would allow. 😄

 

[disq]

How did you make a smooth cut in the plastic water tank?

By shaving away tiny (and sometimes not so tiny) bits using a sharp modeling knife.

 

[cuprajake]

dremel or melt would be better

 

[Doram]

How did you make a smooth cut in the plastic water tank?

I am going to try the solution suggested by @DavecUK, which seems more elegant and doesn't require to cut the water tank. Instead, Dave suggested to connect the OPV discharge hose with a T connector to the hose that goes to the pump, as seen in the photo below.

I ordered a 3-way Y 6mm connection and a 3-way 6mm T connection to do the mod, both brass and from the same eBay Shop:

Y connector - https://www.ebay.co.uk/itm/BRASS-barbed-Hose-Y-Splitter-Joiner-Connector-Available-in-4-sizes/302640867070?ssPageName=STRK%3AMEBIDX%3AIT&var=601489110379&_trksid=p2057872.m2749.l2649

T connector - https://www.ebay.co.uk/itm/SOLID-BRASS-barbed-Hose-T-splitter-joiner-connector-Available-in-6-sizes/301942646786?ssPageName=STRK%3AMEBIDX%3AIT&var=600744504401&_trksid=p2057872.m2749.l2649

DaveC also suggested adding a one-way (no return) valve on the hose between the T connection and the tank. If I understand correctly, this is to make sure that the discharge water will only go to the pump and not back to into the tank, in order to stop the pressure of the OPV discharge from pushing up the in-tank filter (Please correct me if I got this wrong). This valve is optional and is not necessary if no in-tank filter is used. This is the no-return valve: https://www.ebay.co.uk/itm/One-Way-Valve-Sprung-Plastic-Barbed-Non-Return-Inline-Water-Air-Car-Gas-Liquid/251338340002?hash=item3a84eeb6a2:g:5xQAAOxyNExSMi3I

If anyone has tried it and has any experience to share, I would love to hear it before I wreck my machine, lol.