Breville Dual Boiler BES900XL brass OPV and pump mod.

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
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#1: Post by cuppajoe »

Yeah, I know...Just moved to a new place and so far haven't figured out how to do plumb-in other than in the garage. While poking around for a pour over machine a BDB popped up at a price I couldn't pass up. Had one before and was quite happy with its performance, and wanted to pick up a fixer just to check out how it was put together. The machine arrived in surprisingly good condition for the price and have been using it for the morning capps for the last month or so. Brew pressure and pre-infusion behavior was a bit wanky, so decided to have a go at the brass OPV mod and replace the solenoid seals. While at it, figured a pump upgrade wouldn't hurt.

Upgrades are done and brew pressure is stable, with pre-infusion now working as advertised. The thing is actually built well considering the technology/features and price point. Most of the things that get folks dander up are inconsequential, but there were some engineering and build details that got irritating from a service standpoint. Will mention those as I go along.

Will break it down into sections to try and keep posts from getting too long.
David - LMWDP 448

My coffee wasn't strong enough to defend itself - Tom Waits


#2: Post by LukeFlynn »

The plastic OPV in the BDB is probably the most prone component to inconsistency and eventual failure. My 900 was developing a rattle and the bouncing pressure as well. Looking forward to getting my BDB back (or the 920 :D)

I wish that "pro" version of the BDB w/ rotary pump that was shown off a few years back would come to light... maybe one day.

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cuppajoe (original poster)

#3: Post by cuppajoe (original poster) »

First off, no quick disconnects on the wiring harness, everything is crimped. This necessitates flopping exterior panels out of the way while connected to short leads. Got tired of dealing with the top cover, so removed the active heater assembly from it.

There are two access holes in the frame(glass filled resin) to get to the upper pump mount screws. To make thing easier to get to, I decided to move the brain box out of the way.

Good in theory, however Murphy got me. One of the staked on nuts for the pump mount screws was either not properly mounted, or the screw over torqued. In any case, the nut just spun and spent a lovely half hour working on getting the screw out. Here's the steam boiler bracket showing the empty space where the nut should be.

The original pump with the screw and blasted nut.
David - LMWDP 448

My coffee wasn't strong enough to defend itself - Tom Waits

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cuppajoe (original poster)

#4: Post by cuppajoe (original poster) »

That stupid nut added another half hour as it had dropped down behind the bracket, which meant the steam boiler assembly had to be out to get to it and for reinstallation. The assembly is connected at the bottom and could not be removed without a lot of disassembly. Managed to work it out enoigh to retrieve the nut and hold it in place while installing the new pump. The poor QC added an extra hour to what should have been an hour or less job.

Here's the two pump assemblies. The fitting for the steam boiler tube just screws into the top of the OPV with no fuss. The Loctite 577 allows you to orient the OPV and fitting properly with a water tight seal.

Here's the new pump assembly installed along with the new solenoid gasket.

All the new bits for the mod.

Machine is up and running. Brew pressure adjusted to 9.5 bar and holds steady and the pre-infusion is now consistent. These mods should also improve long term reliability as well. My main gripes about the machine's construction were the lack of quick disconnects, poor QC of the subassemblies, and little thought for serviceability. The BDB is not alone in that regard by a long shot.
David - LMWDP 448

My coffee wasn't strong enough to defend itself - Tom Waits


#5: Post by pcrussell50 »

Excellent motivational piece. Thanks for contributing. Part numbers and sizes would be super helpful for the OPV, and the fitting on top of it.

...misleading and dead links removed...

The new machine they sent me, was still a 900XL, but it was a /B version with the 920xl group head and portafilter... and a different scheme for the solenoid than the one you have. It does not have a gasket between the solenoid and the pad. Just a couple of hard, (PTFE?) seals embedded in the recesses of the solenoid base. It does not leak at all, and never has, and doesn't accumulate any gunk, like the older design did.

Anyhow, point being that there are now out in the wild: Original 900/900xl's, /B 900/900xl's, and 920/920xl's, and while they are all but identical in terms of brew path and system logic, there are small differences here and there in terms of gaskets and seals, in which the /b 900's use some of the same stuff as the 920.

LMWDP #553

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cuppajoe (original poster)

#6: Post by cuppajoe (original poster) »

The OPV from partsguru is the same as the one in the 'Nic''s blog -, tho looking at the pics it seems the elbow fitting has a lot of TFT tape to get it sealed for some reason. I used the one that Stefano stocks - ... -valve-opv. it has a 1/8"BSP socket at the top for the elbow and the fitting fits as should.

I picked up the elbow on ebay - ... 1a191175fa. A British outfit who seems about the best source for fittings that go down to these small sizes.

The square solenoid gasket I got from these folks in Canada - ... ial-order/. A tech in Australia confirmed that this is the second version and the current spec is the two teflon discs with the inserts. Those small insert tubes are mission critical.
David - LMWDP 448

My coffee wasn't strong enough to defend itself - Tom Waits

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#7: Post by old442 »

I've thought about doing this as well.
My only change to your mod would be to rotate the OPV and put a hole in the rear cover, with a plug, so I could adjust the OPV without opening the machine.

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#8: Post by erics »

The Loctite 577 allows you to orient the OPV and fitting properly with a water tight seal.
Once you install that OPV, the white seal should work well without any Loctite (I realize this is water under the bridge now) as the entire assembly can simply be rotated to any orientation you want. Of course, the 90 ell fitting is a different matter.

I'm writing from no knowledge of this machine but I would have installed some quick disconnects on the cup warmer element.

Did you use any adhesive on that pump mounting nut?

Nice job and nice pics.

Eric S.
E-mail: erics at rcn dot com

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cuppajoe (original poster)

#9: Post by cuppajoe (original poster) »

Thanks for the kind words Eric.

The 577 was just being anal, after doing a number of machines I've gotten tired of chasing leaks after the thing is reassembled. The O-ring I used is quite a bit thicker than the one that came with the OPV and would probably have been enough.

Yes, quick disconnects was the first thing that came to mind. I have a box of Molex connectors and the crimper somewhere, still going through stuff after moving. I did a quick disconnect mod to the leads going to the back plate on my Quest which definitely made cleaning it a lot easier. Only one more detail to care of, replacing all the O-rings on the boiler fittings, and that should be it for awhile.

No adhesive on the nut. It was difficult enough just getting it back on and the new pump should outlast the rest of the machine. Not sure what would stick stainless to stainless anyway. Maybe J-B Weld, but it would have been a mess and a headache and probably would have ended up gluing the screw in place as well. If I had removed the steam boiler assembly I would have re-staked it.

All things considered, not sure it's necessary to fiddle with the OPV on a regular basis. Easy enough to work it as is for initial adjustment, and the brass OPV should stay in adjustment for a long time.
David - LMWDP 448

My coffee wasn't strong enough to defend itself - Tom Waits


#10: Post by SaqibSaab »

Hey, David and all. Just ordered a brass OPV (Stefano's), the fitting (from the eBay account you linked, David), and a new Ulka pump (off of eBay, exact model shown in your photo above).

My Breville OPV broke while I was trying to adjust the OPV. Was just about to pull trigger on $349 servicing when a question on Coffee Geek ( ... 077#717077) on where to find new Breville OPVs routed me here. I had already seen Nic's blog on a brass OPV, but it didn't seem like something I could do. Seeing this new thread has been helpful and motivating. Praying that I can fix this!

My BDB was ordered refurbished from Breville Authorized Clearance eBay Canada account in December 2014, OPV was adjusted December 2015, OPV broke December 2016. December is all about milestones with my BDB, it seems.

1. Do I need to order a new solenoid gasket? If so, why?
2. I live in Chicago in the US, how long did all your parts take to come in?