# Redirect OPV waste back to tank



## unoll (Jan 22, 2014)

It bugs me that loads of decent water goes straight into my drip tray when brewing a shot. Have any Brewtus users on here redirected the OPV back into the reservoir tank? I can't imagine it would be that difficult. Any useful hints or advice from those who've done (or tried), it already would be appreciated.


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## froggystyle (Oct 30, 2013)

Do grinds come back through though?


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## unoll (Jan 22, 2014)

Short answer = no

Long answer = see the diagram on page 3 http://www.bellabarista.co.uk/pdf/ExpobarOfficeLeva-DualBoilerv4CoffeeMachine.pdf . The flow goes reservoir - pump - OPV - boiler - group head. Any grounds will go through the bottom of the E61 head.


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## froggystyle (Oct 30, 2013)

Seems a lot of hassle for a very small amount of water.


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## froggystyle (Oct 30, 2013)

That picture shows the water going from the opv back into the tank already?


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## unoll (Jan 22, 2014)

Unfortunately for my machine, that bit of the diagram is wrong but that's a good point. The photo of the machine however shows the same water outlet from OPV into drip tray. Anyone know if the excess water used to go back into the tank and if they changed it for some reason?

Froggy, it's actually more water than you may think and the effect of rerouting is twofold: reduced refilling of water tank with filtered or bottled water (reduced cost) & reduced emptying of the drip tray which can get very full very quickly. I can't imagine the mod is more complex or hassletastic than routing a length of silicon tube from the OPV to the tank.I could always just plumb in the machine (and buy a water filter etc etc), and route the drip tray to the house drainage, but that''s not an option at the moment.


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## froggystyle (Oct 30, 2013)

i see now, yes i would imagine its just a length of tube then from opv to tank as you say, isnt this how the classic works?


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## timmyjj21 (May 10, 2015)

Indeed, that's how the classic works. Its crazy that your machine was not created this way!


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## unoll (Jan 22, 2014)

I know, it just seems daft. I upgraded from a classic to the Brewtus and the relatively small water tank on the classic used to last ages. It kind of makes me wonder if there's a reason for it............. Maybe they just assumed no-one would care if it was all plumbed in.

Regardless, I've just ordered a length of tubing off ebay (£1.30 on a slow boat/plane from Hong Kong), so I'll do the mod and report back.


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## tictok (Dec 1, 2013)

I'd be keen to see how well this works out. Always niggles me a little watching my bottled water being poured into waste.


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## hotmetal (Oct 31, 2013)

Sorry guys I'm maybe being thick but what water are we talking about? The drips from the expansion valve when the machine warms up, or the water that comes out of the e61 exhaust when you drop the lever after pulling the shot? (Bearing in mind I have the Rocket db which is similar but different)


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## Xpenno (Nov 12, 2012)

hotmetal said:


> Sorry guys I'm maybe being thick but what water are we talking about? The drips from the expansion valve when the machine warms up, or the water that comes out of the e61 exhaust when you drop the lever after pulling the shot? (Bearing in mind I have the Rocket db which is similar but different)


Hey mate, the OPV sits after the brew boiler and before the puck. It's set at a constant pressure (i.e. 9bar usually) the since pump generates a higher pressure than 9bar this extra water exits via the OPV value to ensure 9bar at the puck. If your pump generates a flow that equates to 12bar for example then 9bar of pressure need to be released via OPV.

Hopefully that sort of makes sense :S


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## hotmetal (Oct 31, 2013)

Cheers Spence, so does that extra water go straight into the drip tray during the shot then? On my Rocket the only water I see is a few drops as the boiler heats up (water expands and comes out of a little round valve above the drip tray) and the 'exhaust' water that comes out of the bottom of the e61 gubbins at the end of a shot when you drop the lever.


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## DoubleShot (Apr 23, 2014)

Yes, if I've understood this correctly, it's the wasted water that exits the OPV and into the back of your drip tray once you drop the lever after pulling a shot. Op was asking if this can't be re-directed back into the water tank.

Just the other day I was working out how many bottles of water I've been through since mid January when I started making espresso and its 1 x 5 litre and 36 x 1.5 litres. I don't think I make anywhere near as much as most do on here. A lot of it imo is from cleaning and 'wasted' water from the OPV.


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## DavecUK (Aug 6, 2013)

hotmetal said:


> Cheers Spence, so does that extra water go straight into the drip tray during the shot then? On my Rocket the only water I see is a few drops as the boiler heats up (water expands and comes out of a little round valve above the drip tray) and the 'exhaust' water that comes out of the bottom of the e61 gubbins at the end of a shot when you drop the lever.


Vibration pump vs Rotary pump, different system of pressure regulation...


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## Rhys (Dec 21, 2014)

DoubleShot said:


> Yes, if I've understood this correctly, it's the wasted water that exits the OPV and into the back of your drip tray once you drop the lever after pulling a shot. Op was asking if this can't be re-directed back into the water tank.
> 
> Just the other day I was working out how many bottles of water I've been through since mid January when I started making espresso and its 1 x 5 litre and 36 x 1.5 litres. I don't think I make anywhere near as much as most do on here. A lot of it imo is from cleaning and 'wasted' water from the OPV.


I read it as the excess water from the OPV that's released when the pressure is too great - before it reaches the puck. The same water that is returned via the second tube on a Gaggia Classic's water tank.


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## Xpenno (Nov 12, 2012)

Rhys said:


> I read it as the excess water from the OPV that's released when the pressure is too great - before it reaches the puck. The same water that is returned via the second tube on a Gaggia Classic's water tank.


Yup, that's how I understand it. I could be wrong though


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## Xpenno (Nov 12, 2012)

hotmetal said:


> Cheers Spence, so does that extra water go straight into the drip tray during the shot then? On my Rocket the only water I see is a few drops as the boiler heats up (water expands and comes out of a little round valve above the drip tray) and the 'exhaust' water that comes out of the bottom of the e61 gubbins at the end of a shot when you drop the lever.


Could go back to the tank depends on design of the machine. The waste from the group is different, this just relieves any excess pressure in the group once the shot is finished.

Good explanation of the OPV here

http://coffeetime.wdfiles.com/local--files/opv-over-pressure-valve/OPV_Valve.pdf


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## Xpenno (Nov 12, 2012)

DoubleShot said:


> Yes, if I've understood this correctly, it's the wasted water that exits the OPV and into the back of your drip tray once you drop the lever after pulling a shot. Op was asking if this can't be re-directed back into the water tank.
> 
> Just the other day I was working out how many bottles of water I've been through since mid January when I started making espresso and its 1 x 5 litre and 36 x 1.5 litres. I don't think I make anywhere near as much as most do on here. A lot of it imo is from cleaning and 'wasted' water from the OPV.


Don't think this is correct, the stuff that goes to the drip tray after a shot is from a group waste valve rather that OPV. OPV controls brew pressure during the shot. The group waste would contain coffee and coffee particles so you wouldn't want this going back to your water tank. I would have thought that the water from the OPV would go back to the tank as it could surely fill a drip tray pretty quickly. The only reason I could think of not to do this would be having warm water sat in the tank rather than cold water etc... but even then it get's boiled again before you drink it.


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## DoubleShot (Apr 23, 2014)

Okay, getting my exhaust valve and OPV mixed up! I had never thought anything more of it other than it seemed a lot of bottled water being wasted. Certainly didn't think anything could be done about it in order to re-route it or prevent the wastage.


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## Xpenno (Nov 12, 2012)

DoubleShot said:


> Okay, getting my exhaust valve and OPV mixed up! I had never thought anything more of it other than it seemed a lot of bottled water being wasted. Certainly didn't think anything could be done about it in order to re-route it or prevent the wastage.


I've never measured the output but I wouldn't think it's be that much in the grand scheme of flushing etc... PITA to measure on the Vesuvius as well as the exhaust is pretty sung against the drip tray and it's pretty high powered so would probably end up covering me in scalding water


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## DoubleShot (Apr 23, 2014)

I think a fair amount I see filling up the drip tray is all the backflushing I do. Usually each time I change beans which sometimes has been after only two days from the previous backflushing and I usually do five separate cycles.


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## Xpenno (Nov 12, 2012)

DoubleShot said:


> I think a fair amount I see filling up the drip tray is all the backflushing I do. Usually each time I change beans which sometimes has been after only two days from the previous backflushing and I usually do five separate cycles.


Yeah, all types of flushing attribute to quite a bit of wastage, a necessary evil


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## hotmetal (Oct 31, 2013)

Sorry I think I threw a bit of a spanner in the works by asking. It sounded an interesting discussion but as DavecUK has explained my machine has a rotary pump so the machine this thread is about has a completely different system. Hence my confusion.


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## unoll (Jan 22, 2014)

Mod successful! As suspected it's simply a case of opening up the machine and disconnecting the tube that leads to waste from the opv and then connecting a new tube which goes straight back to the water tank. Easy, cheap and a good way to reclaim back some water. All you need is a 1m length of 6mm od 2mm wall silicone tube and you're away.

It seems there's some confusion about which machine I'm talking about. This mod relates to the expobar office leva dual boiler iv.

Below image is a close up of the opv waste connection. The top tube is the one that needs switching.


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## Russ (Nov 15, 2011)

By doing this mod when you back flush doesn't the waste water go back into the water tank, not good if you are using puly caff etc?

Russ


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## unoll (Jan 22, 2014)

Hi Russ, no it doesn't. Its probably easier just reading through the previous thread posts and looking at the diagram i attached way back in the thread. Also watch the video on youtube about how an e61 group head works.


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## Russ (Nov 15, 2011)

This post got me scratching my head a little but I think I've worked it out.

I have the plumb in only version of the mkIV with the vibe pump. Unoll has the vibe pump mkIV machine that has the plumb in option. They are slightly different.

My version already takes OPV water back to the tank not the drip tray so no mod required.

Unoll's plumb in option machine has the OPV water directed to the drip tray and as he rightly says the mod is a great way of saving this water (its going to be quite a bit!)

The only thing to remember would be if you did the mod and then decided to plumb in the machine, you'd have to reverse it otherwise the water tank would eventually overflow with OPV water.

Cheers

Russ


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## Dylan (Dec 5, 2011)

This entire thread thoroughly confused me, but I think Russ's post has explained it.

This must just be a feature of machines that are designed to be plumbed in then, as it would be mental for a tank fed machine to constantly pump water into the drip tray.

Really, if the machine was sold to the OP as a tank machine this 'mod' really should have been carried out by the retailer or manufacturer.


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## Russ (Nov 15, 2011)

@Dylan

I reckon there's a lot of tank fed/plumable versions out there, its the model i'd have bought if I was buying new to keep my options open.

Without the mod that's a lot of wasted presumably bottled water.....


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## unoll (Jan 22, 2014)

Apologies to all for any confusion my posts may have caused. I guess I should've been clearer that I have a switchable machine with a vibe pump. To clarify, I was always aware that I was going to get a plumb or tank unit.

The mod is still going strong by the way. I'll just need to remember to switch the tubes over if I ever plumb in.


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## Dylan (Dec 5, 2011)

@Russ

Yea, I guess it would be ideal if it is made explicitly clear to the buyer that this is how a machine that was designed to be plumbed in operates, and a mod may be needed if you dont want a load of waste water.


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## Russ (Nov 15, 2011)

@unoll

No need to apologise, its a great mod!

Short sighted of Expobar not to have come up with a different solution for the dual option machine IMO.

Cheers

Russ


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