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Mara X: Redirect OPV discharge water from drip tray to re-use – easy mod instructions (with pics)

76K views 340 replies 60 participants last post by  marknewham 
#1 · (Edited by Moderator)
What?
This easy mod is to re-route the water discharged from the overpressure valve (OPV) so that instead of being dumped in the drip tray and wasted, it will get reused in the machine. The mod is easy, cheap, invisible, and completely reversible.

Why?
One of the very few complaints about the Mara X is that it dumps the OPV discharge water into the drip tray. Re-routing will (a) reduce water waste; (b) reduce the water that ends in the drip tray. This results in less need to fill the tank and less emptying of the tray.

How much water will be saved? Is this worth doing?
The amount of OPV water discharge varies by shot time and puck resistance (For example, @disq measured that 85ml of water was reclaimed in a ~49-second shot; My own experiment showed that water in the drip tray after one heating cycle and shot reduced from 125mm before re-routing to 40mm after - so about the same). This is not a huge amount, but it adds up, and if you invest in the water (bottled, re-mineralise, etc.), you might not want to through it away and fill the drip tray with it.

So why does Lelit dump the water into the drip tray? Is there a disadvantage to re-routing?
Many (most) tanked machines return the OPV discharge water back to the tank. (e.g. Gaggia Classic, Rancilio Silvia, Lelit Elizabeth and more). This was also the case in the first prototype of the Mara X, but that was changed in the production model.

According to @DavecUK, the dumping of the water to the drip tray was meant to enable provision for a neat in-tank filter in the bottom-fed water tank, with no messy tubes entering from the top. However, you can do this mod and still use the in-tank filter; and if you don't use the filter - it's even easier.

How hard is it to do the mode?
This mod is very easy. I took my time and maybe spent an hour, but the actual job is very quick: just pop a few tubes from their fittings and connect them differently.

What parts are needed?
The mod requires two 3-way 6mm connectors (cost £6) and that's it. I used one Y-shape and one T-shape, but you can do it with two Y connectors. I used brass for durability and heat resistance, but you might be able to get away with plastic connectors).

Y connector: BRASS barbed Hose "Y" Splitter Joiner Connector. Available in 4 sizes | eBay

T connector: SOLID BRASS barbed Hose "T" splitter/joiner/connector. Available in 6 sizes | eBay

(Halfords sell a pair of plastic Y connectors if you don't want to wait for brass to come in the post: Halfords Hose Connector Y Piece 6mm HFX373 | Halfords UK).

Optional parts:
@DavecUK suggested fitting a one-way no-return valve if you want to keep using the in-tank filter: One Way Valve Sprung Plastic Barbed Non-Return Inline Water Air Car Gas Liquid | eBay. (This part is to ensure that water from the OPV discharge will not push back to the tank, potentially lifting the in-tank filter from its seat).

@MediumRoastSteam suggested using cable ties on the connections to secure them, and extra silicone tubing so that you can keep the original tubing intact if you want to reverse the mod. I didn't use cable ties as my fittings a barbed and seem very secure as they are. I also didn't need any extra tubing: I 'borrowed' 4-5cm of tube from the in-tank hose loop that I don't need (because I don't use the filter), and kept the original tubes inside the machine intact (so everything is reversible to original condition). However, I found that the tube from the bottom of the tank to the pump is long enough, so if I wanted I could do all the connections without any need for extra tubing borrowed from the tank.

I am convinced, what do I need to do (see pics below)?
1) Remove the top panel and the main part of the case of the machine. See instructions in DaveC's excellent video here:

2) Identify the OPV (pic below). Follow the hose that comes out of it. It terminates in a brass X connector.

3) Carefully remove the OPV hose from the X connector, and re-route it behind the boiler to the other side of the machine (to where the hose from the bottom of the tank enters the pump - pic below).

4) Either cut the hose connected to the pump a few cm above the entry and connect the T connector to the hose (or use a few cm of new hose to connect the T connector to the pump's entry). Use the free connection on the T to connect the hose from the OPV. That's the re-routing of the OPV discharge done.**

5) (optional): if you want to use the in-tank filter, connect a one-way (no-return) valve on the hose between the tank and the pump. This will ensure the OPV discharge water will not return to the tank and push against the filter (I didn't do this stage).

6) To finish the job, go back to the X connector where the OPV discharge hose was originally connected. Remove the 3 remaining hoses that are connected to the X connector (safety valve, solenoid, and drip tray), and connect them to the new Y hose connector. Secure the connections with cable ties if you want (I didn't), and also secure the Y connector to the electrical wires (as it was originally with the X connector). (Bottom pic shows this before and after)

**An even simpler option: Just follow steps 1-3 and 6, but after removing the OPV discharge hose from the X connector route it back to the water tank (requires making a cut in the top of the tank so that the cover of the tank can sit flush), or route the hose to a bottle next to or under the machine. Both these options are possible but of course less elegant than the proposed full mod.

That's it, all done. (To be safe, it might be a good idea to run the machine (carefully) with the case off to see that everything is working as it should and you have no leaks before fitting back the case (to be honest, I didn't bother).

Enjoy the machine with less water waste and less emptying of drip tray. 😊

Credits and thanks: @DavecUK, @disq, @MediumRoastSteam and all other fantastic members here for their support and contribution.

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#4 ·
Thanks for posting this. Sounds like a v useful mod. In terms of the non-return valve, if that is put in the tank feed tube to pump (before the Y piece), if the OPV releases water when the pump isn't running, won't that cause a pressure build up against the pump in the OPV to pump re-routed tube? Or will it flow through it?
 
#5 ·
I didn't use the non-return valve, so this better be answered by @DavecUK. However, just from common sense - the OPV releases the pressure from the pump, so it only discharges water when the pump is running. I can't think of a situation where the OPV will push water when the pump is idle, but maybe I am wrong?
 
#14 ·
this mod is even better than the traditional approach mentioned above as lukewarm water does not go back to the tank.

If you use bottled water or home distilled, it's a no brainier IMO
I totally agree. I said it's reversible, but I can't see why anyone would ever want to go back. I would want it even if I used tap water, just for the sake of getting less water in the tray (45ml per shot vs. 120-150ml that I was getting before. With the amount I was getting I had to empty every day, now it will just empty when I want to clean the tray). Less need to fill the tank is also a bonus. Finally, as it's all under the hood, you still get to keep the neat bottom-fed tank, no hoses to remove and splash when you take the tank out.

It really feels like a win-win-win situation. It works and feels as something that came out of the factory, not as a mod, because it just makes the machine better, period. Unless I am missing something important, I wouldn't at all be surprised if Lelit will do it themselves next time they revise the Mara X.
 
#15 ·
Firstly thank you so much for the detailed guide. I would be even more lost without it and wouldn't even attempt it.
I am awful at DIY stuff, parts ordered. Seems simple enough?

Would be easier to put the pictures underneath each step rather than at the bottom of the post. Maybe this is just be being terrible at following.

4) Either cut the hose connected to the pump a few cm above the entry and connect the T connector to the hose (or use a few cm of new hose to connect the T connector to the pump's entry). Use the free connection on the T to connect the hose from the OPV. That's the re-routing of the OPV discharge done.**
Is the new hose the hose inside the water filter? I use RO water so I guess I don't need to use the provided water filter, I just did because my plumed RO filter change is long overdue. What size hose would I be looking for if I wanted to buy a spare?

Would be great if someone made a video of this to help the DIY blind crowd!!
Seems like a 10 minute max job - am I right?
 
#16 ·
Is the new hose the hose inside the water filter? I use RO water so I guess I don't need to use the provided water filter, I just did because my plumed RO filter change is long overdue. What size hose would I be looking for if I wanted to buy a spare?
It will be very clear and simple once you open the machine. In stage 4 that you asked about - The original situation is you have a hose going from the bottom of the water tank to the pump entry. This hose is feeding water to the pump. Let's call it hose A.

Now you have a new hose (coming from the OPV) - This is hose B.

You want to join Hose B to Hose A, so that both feed water to the pump entry. You do this by creating a T junction (the T connector). You just connect the T anywhere on Hose A (using 2 of the 3 ways on the T), and then connect hose B to the third connection on the T. Now both hoses A and B feed the pump. Done.

To connect the T connector to hose A, you either cut it anywhere, and connect the T to the middle of the hose, or you connect the T to the end of the existing hose A, and add a small piece of new hose, and connect this bit to the pump entry - both are basically the same thing. You really don't need to buy more hose, because the existing hose A is long enough. If you did want to add a small piece to the end, the loop hose inside the tank (which you don't need if you don't use the filter), is exactly the same as hose A. (Even if you do cut a small bit of the loop hose in the tank, you still have plenty to use the in tank filter in the future if you wanted to).

I hope this makes sense, but it will for sure be clearer when you have the case off.
 
#19 · (Edited by Moderator)
@kico - I think you are turning this innocent puppy of a mod into a 7-headed monster! 😂👍 The instructions there are super easy to follow, as @Doram say, once you open the machine and locate the OPV, the hose, the X fitting and the pump, it will become extremely clear.

The OPV and the pump are the same as in the Elizabeth. You'll need a food safe silicone hose which is 5mm I.D. (inner diameter) and 8.5mm or 8.mm O.D. Outer diameter if you want to keep some as spare.

It's always good to have some hoses as spare handy just in case a vacuum breaker, solenoid breaks or a mod needs doing... 🙂 - That's why I have 2 metres of that spare at home 🙂

Like this: https://www.ebay.co.uk/itm/Clear-Silicone-Tubing-Hose-Pipe-Pond-Aquarium-Fish-Tank-Air-Pump-AFS-Tube-FDA/130771449103?ssPageName=STRK%3AMEBIDX%3AIT&var=430096423714&_trksid=p2060353.m1438.l2649
 
#21 · (Edited by Moderator)
@spasypaddyThe Bianca doesn't deal with water the same way as it has a rotary pump. If you have water pissing out of the vent above the drip tray during a shot, then something isn't adjusted correctly. The rotary pumps recycle excess water around what is called a balanced bypass system...basically the excess output is routed back to the input of the pump, via an internal channel/spring, valve system.

After the shot the small amount of water that comes out of that fitting on the front panel is due to water expansion in the brew boiler as it heats the incoming cold water.
 
#22 ·
@spasypaddyThe Bianca doesn't deal with water the same way as it has a rotary pump. If you have water pissing out of the vent above the drip tray during a shot, then something isn't adjusted correctly. The rotary pumps recycle excess water around what is called a balanced bypass system...basically the excess output is routed back to the input of the pump, via an internal channel/spring, valve system.

After the shot the small amount of water that comes out of that fitting on the front panel is due to water expansion in the brew boiler as it heats the incoming cold water.
so there isnt a huge amount of waste then? i dont have the pissing thing you talk about, just a dump of water at the end of a shot. so im glad im not wasting more water than necessary! Thanks
 
#25 ·
Thanks for the great instructions @Doram. I did the mod yesterday without any problems. I use the in-tank filter and tried without the one-way-valve. Everything works flawlessly and I couldn't be happier. The reduction in waste water is enormous. Now it feels the galleons of water I schlepp to my apartment land in my stomach instead of the drip tray. Much better overall experience.
 
#26 ·
Interesting re the one way valve. I have the bits coming to do the mod on mine tomorrow or Tuesday, and was going to fit a one way valve.

I wonder what the thinking was behind it being needed? I'd prefer to minimise the amount of stuff inside if I can (one less thing to go wrong in the future).
 
#27 · (Edited by Moderator)
Interesting re the one way valve. I have the bits coming to do the mod on mine tomorrow or Tuesday, and was going to fit a one way valve.

I wonder what the thinking was behind it being needed? I'd prefer to minimise the amount of stuff inside if I can (one less thing to go wrong in the future).
The one way no-return valve idea is @DavecUK's, so he could probably explain it better, but my understanding is that when the tank is sitting in the machine, the bottom valve is just open and enables water to go both out of the tank and into it. In this situation, if water is coming out of the OPV faster than the pump is pulling it, the excess discharge water from the OPV will enter the tank from the bottom opening, and potentially dislodge the in-tank filter (if used).

If you don't want to do more than is needed (my rational exactly), but you want to use the filter, you can start without the no-return valve, fit a filter in the tank and see what happens. If it works fine, maybe you don't need the no-return valve. If the filter is pushed out, it should be easy enough to put the no-return valve on the hose that goes to the tank.
 
#33 ·
I tried the mod and on my machine pump is pulling water from OPV. I can see it when machine is open that small bubbles are moving in the tube going from OPV. In some rare cases it does not happen and then it seems to work normally and pressure is building up. But if it happens then pressure is not rising and stays at 2 bars. The first day it seemed to work but pressure was fluctuating between 8-10 bars. Now it rarely builds pressure and just pulls water from OPV even at 2 bars. I'm not sure sure how OPV works and if something could break inside.

If I disconnect OPV tube from the pump then everything seems to work fine. Pressure reaches 10 bars and does not fluctuate.

I was discussing it with @Doram and he does not see this on his machine. Any ideas if its faulty OPV or something else? I would like this mod if anyone has ideas what else can I try.

I used x2 6mm brass T splitters. I tried to swap reservoir tube with OPV tube on the splitter but it didn't change anything. When I disconnect OPV tube from the pump them water is not flowing from OPV before reaching 10 bars (as it should be).
 
#34 ·
Update: I gave it another try. Disconnected reservoir and OPV tubes. Tried to suck water from both 😅. It it really hard to pull water from OPV and water from reservoir is flowing all by itself because of pressure from reservoir. Now I think pump is not pulling water from OPV but rather just not building pressure because of air bubbles. So I tried to get the air out of the tubes before reconnecting everything. It is working right now but I noticed that some air gets into OPV tube after pulling the shot. And I'm worried it will cause troubles for the pump again.

Any ideas if its normal to get air bubbles from OPV?
 
#35 ·
Update: I gave it another try. Disconnected reservoir and OPV tubes. Tried to suck water from both 😅. It it really hard to pull water from OPV and water from reservoir is flowing all by itself because of pressure from reservoir. Now I think pump is not pulling water from OPV but rather just not building pressure because of air bubbles. So I tried to get the air out of the tubes before reconnecting everything. It is working right now but I noticed that some air gets into OPV tube after pulling the shot. And I'm worried it will cause troubles for the pump again.

Any ideas if its normal to get air bubbles from OPV?
@DavecUK - My understanding is that @iseebirdsflyis getting a pressure issue when the OPV discharge hose is re-routed to the pump inlet hose as I did myself. For me this doesn't change anything, and the machine is working exactly as before (accept for the intended purpose of not dumping water to the tray) - no issues whatsoever. I am not getting any pressure fluctuations during the shot and/or with a blind basket as happens to him, and don't see how the mod could cause that. Any idea what could be causing such an issue on his machine or what he can do to try and solve it?
 
#36 ·
After the night I can see that the tube going from OPV is full of air instead of water. Turning the pump with blind filter built the pressure to 10 bars but then OPV started pushing water and no surprise all the air from the tube was pushed to the pump and that caused pressure to fluctuate. After a few seconds steam pressure gauge started rising rapidly going above 3 bar. I turned off the pump and opened steam to drop the pressure.

Now I'm narrowing the problem to the air in the tube from OPV after the machine is standing idle for a few hours. I don't know where this air comes from and if it can be avoided.
 
#38 ·
When the mod is reverted, everything works as expected. So the OPV is not at fault here. I don't want to say much here because I'm not hydraulics expert, but, if you draw the mod on a piece of paper, it becomes clear that the pump then "sucks" from two places (from the pipe from the OPV and the tank). The OPV pipe would most of the time be primed, full of water, but that's obviously not the case in @iseebirdsfly's case. I wonder... Is it doing that because the hose is empty at the start of the mod? Once full of water - i.e.: do some backflushing - is it an issue subsequently?
 
#39 ·
I think without photos and video to confirm what's been done, the sound and what's been happening....it's tricky. Certainly if the expansion valve output tube was routed back to the tank (via the top as in Elizabeth), then there wouldn't be a problem. The first MaraX prototype I have actually routes the water back to the tank in the same way as Elizabeth and the tamp is a simple drop in with two tubes from the top.

Really, there is no reason for air to be coming from the expansion valve...there is only one place it can leak in from...the top group valve. If the expansion valve was letting air in, it would simply draw water from the tank, if it was coming in via the pump inlet, the same. The amount of air would be small and would show itself as some small delay water came from the group until prior to the mod.

So now I don't know what's going on
 
#43 ·
Has anyone done this mod yet including a one way valve?

I am trying to think where best to put it - in pipe from the bottom of the tank the Y piece, or in the tank in the tube from the filter to the bottom of tank?

Not sure it will matter...
Have you tried it without the valve? I'm not sure you really need it even with filter. It is not be a problem if some water gets back to the reservoir. The only concern is that the stream would lift the filter. Given the diameter of the filter and that there is always a gap between it and the bottom I doubt it will happen. I actually would be more worried that it cannot get back into reservoir when you are doing backflush with blind filter. Anyway you can always add the valve later inside the tank.
 
#41 ·
So as I said the tube going from OPV was full of air in the morning. I tried to get it out by mounting blind filter to push the air into the pump and then removing it to get the air out to the group head. The machine is working for now. I'll wait and see if it fills with air again and I will make a video if it happens again.

The water in the OPV tube is vibrating and air bubbles are moving when the pump is on and this is why I was thinking that it suck water out of OPV. But maybe suction is just making water move inside the tube like some kind of turbulence.

I also did one small change by switching reservoir tube with OPV tube near the pump so reservoir tube is connected from the top and OPV from the side now. The idea is that maybe some small air bubbles get in from reservoir and build up in OPV tube. At least it should not be worse :)

p.s: I don't know the internals of the machine but I have good understanding of physics, math and systems in general as a software engineer. I'm sure I connected everything properly and I can slowly get the air out. I just wanted to confirm that it is not supposed to get in. Could it happen if some air was trapped inside the boiler? So far 4h passed and there is no air in the tube, fingers crossed.
 
#42 ·
I also did one small change by switching reservoir tube with OPV tube near the pump so reservoir tube is connected from the top and OPV from the side now. The idea is that maybe some small air bubbles get in from reservoir and build up in OPV tube. At least it should not be worse :)
Is the problem happening with this setup? Or did you change in trying to "fix" it?
 
#45 · (Edited by Moderator)
Here is a small video to show how the mod works on my machine. (the coffee is a few months old and ground too coarse, so shot is fast [didn't mean to drink it, lol], but you can still see what is going on).

Note that the pressure ramp up is normal, and the pressure is held at 10 bar throughout the shot (usually it holds at ~10,5, but as I said this is old coffee ground too coarse). Also note that no water is entering the drip tray during the shot, which is the reason we are here. 🙂



Thanks @MediumRoastSteam for the tip on how to upload the video properly.
 
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