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Bunn ES-1A rebuild
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Tex
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Tex
Joined: 27 Apr 2006
Posts: 840
Location: Texas - That's God's country to everyone else!
Expertise: Professional

Espresso: Bunn ES-1A (PID'd), Gaggia...
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Posted Sat Sep 30, 2006, 8:05pm
Subject: Bunn ES-1A rebuild
 

I bought a Bunn ES-1A on eBay. After it arrived I stripped the panels to get a look inside. In general it was very clean; a leak at the heating element flange & that was it. I think I may have gotten one of those mythical "good deals" eBay isn't that well known for.

I tried removing the element but I couldn't get it through the flange opening. I finally removed the element (needed to use a vice grip to get the element squeezed to a narrower profile). No wonder it leaked, the gasket was completely crystallized. After I soaked the elements flange in an acidic solution I was able to remove most of it with a gasket scraper. The rest came off with a Dremel wire brush. The boiler flange wasn't as difficult to clean up, just a light touch with the Dremel.

While looking for a new gasket I found most Gaggia ES makes (Futuremat, Visacrem, etc.) offer two gaskets, 1) ALIMENTARY GASKET, 2) TEFLON
RESISTANCE GASKET. Alimentary refers to food or the digestive tract so I'm assuming that #2 is approved for use with food preparation equipment. So what is #1 used for, making coffee for chimps? Or are they supposed to both be used together? There is what looks like an O-ring groove cut into both flanges but the was no O-ring when I disassembled it. I'm tempted to revert to my hot-rodding roots & use a copper O-ring & RTF sealant. Hey, it used to hold Keith Black hemis together, it should do for this application.

After taking a look in the boiler it appears that at some point it was used with straight tap water because there was at least a half inch of mineral
flakes laying on the bottom of the boiler. If I invert the boiler so the element flanges opening points down I can rinse the sediment out with the
garden hose. Other than that the tank looks clean & if the various gaskets & seals on the machine look like the few I've already looked at this machine will be a snap to clean up. Wish me luck?
--
Robert (Bunn lovers do have a different perspective!) Harmon
http://tinyurl.com/pou2y
http://tinyurl.com/psfob
http://tinyurl.com/fkd6r

Tex: boiler 1.jpg
(Click for larger image)
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jimoncaffeine
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Joined: 5 Oct 2005
Posts: 34
Location: Woodinville, WA
Expertise: I love coffee

Espresso: La Marzocco GS 1 group, La...
Grinder: Mazzer SJs, Rossi RR45s,...
Roaster: PID'ed Poppery 1, Behmor
Posted Sun Oct 1, 2006, 9:40am
Subject: Re: Bunn ES-1A rebuild
 

Robert,

Sounds like a fun project!  While I don't have any Bunn experience, I just finished a Faema Compact S rebuild a couple of weeks ago.  

If you haven't already, check out www.cafeparts.com for replacement parts.  They seem to be pretty reasonable on parts price though the shipping fee seems to be a flat rate up to a given weight/size.  (i.e. a $4 knob costs the same to ship as the same knob + grinder burs + a switch + a Sirai rebuild kit + etc.)

Check out www.espressoparts.com as well to see if they have anything you need.  I don't see a lot of Gaggia parts there but lots of the various manufactuer's machines use the same or similar parts.

I had several element gaskets for my Faema and all of them seemed to be wrong.  Mine also had a small indentation in about the middle of the mating surfaces.  There was no o-ring in mine either.  Finally I just used the teflon gasket, since it was the right inside diameter, and dremelled the outside down to fit.  The other gasket was a fiber type material and was about the same dimensions as the teflon one but I reasoned that the teflon one would be more friendly with a little persuasion via the dremel (cleaner cuts) than the fiber one.  It went together without a hitch and no leaks.

While RTV is good for the care and feeding of an engine, I'm not sure I'd want to have it in my coffee... ;)  

While my boiler was out, I filled a 5 gallon bucket with hot water and citric acid.  I then soaked the boiler and everything water-proof for about 4 hours - occasionally pulling the boiler for a scrub with a brass brush on any stubborn bits of scale.  It cleaned everything up nicely.  If left in for too long, the non-brass surfaced parts will plate a tiny bit with copper.  (The chrome-plated group head took on a faintly copper-ish color.) but a quick scrub with a brass brush set things right.  Stick with brass brushes and not stainless ones as the stainless will leave a 'lasting' impression on the softer brass and copper.  (I even 'bodged' together a temporary pump electrical connection so I could de-scale inside there too.)

While everything was out, I dissassembled all of the components reasoning that I didn't want to go back in there for a while and o-rings and gaskets are generally cheap.  If you go this route, take A LOT of pictures, so you can get the re-assembly right.  Also, its a snap to insulate the boiler when its lying on your work-bench rather than when its installed in the machine.  It will make it more efficient - it will hold heat better and your thermostat and element will cycle less making them last longer.

My water and steam valves seemed to work ok but after the rebuild I was amazed at the difference!  Parts were cheap for those as well.  (An o-ring, a couple of gaskets and a valve seat.)

A couple of things that I found that helped the process or made things a bit easier to clean stuff up:

- Ceramic cooktop cleaner: I use a brand called Cerama Bryte.  This works wonders on both mirror-finish and brushed finish stainless steel for cleanups.  It gets off sticker adhesive, stains, etc. and has never scratched any surface that I've used it on.  I then follow it up with a stainless steel cleaner to finish it off.

- Some of the food-grade grease that's available at the espresso parts places.

Good luck on your project!  I don't regret doing mine for an instant.  Though now I have one too many machines...  (At least, my wife thinks so... ;) )


Regards,

Jim
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Tex
Senior Member
Tex
Joined: 27 Apr 2006
Posts: 840
Location: Texas - That's God's country to everyone else!
Expertise: Professional

Espresso: Bunn ES-1A (PID'd), Gaggia...
Grinder: Rancilio MD50
Vac Pot: Way too many vintage Silex...
Drip: Melitta Clarity
Roaster: TurboCrazy &...
Posted Sun Oct 1, 2006, 2:01pm
Subject: Re: Bunn ES-1A rebuild
 

Right RTV not RTF. According to LocTite it's certified by NSF & there are not many professional espresso technicians without a tube of it in their toolbox. Thanks for the tips on those web sites; cafeparts.com does list Gaggia/Bunn parts. I ordered two Teflon gaskets plus an assortment of O-rings and a new set of burrs for my Mazzer.

I'm probably not going to perform as radical a rebuild as you; when I get the element back in I'll perform a series of pressure tests. If there are no other leaks I'll button it back up & give it a try.

Here's a link to the machine's condition upon arrival: http://home.earthlink.net/~r_harmon/Bunn/

More to follow next week.

 
Tex
--
http://www.tinyurl.com/mb4uj - My coffee pages.

http://www.tinyurl.com/2tnv87 - My 'Guidelines For Newbies' page.

http://www.tinyurl.com/2cr3e2 - I sell things for friends & neighbors here. Can I list something for you?

http://www.tinyurl.com/235dfr - BUG is Bunn User's Group (espresso)
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jimoncaffeine
Senior Member


Joined: 5 Oct 2005
Posts: 34
Location: Woodinville, WA
Expertise: I love coffee

Espresso: La Marzocco GS 1 group, La...
Grinder: Mazzer SJs, Rossi RR45s,...
Roaster: PID'ed Poppery 1, Behmor
Posted Mon Oct 2, 2006, 7:26am
Subject: Re: Bunn ES-1A rebuild
 

Robert,

Which RTV is NSF?  I couldn't find the info on their web site.  RTV *would* be very useful in a lot of places!

I just ordered some parts for my new La San Marco machine and some new burrs for my RR45.  Its sort of enabling to have the shipping level at a fixed rate. :)

My rebuild project took took 2 weeks (averaging about 1 hour per evening and about 4 hours per weekend.).   Some of that time was waiting for parts.  That machine started as just a box of parts though its a bit simpler design (no dosing mechanism) than the Automatic that you have.   Seems like most of the time was spent prepping the frame for paint and stripping paint off of the plastic body panels.  (The prior owner painted them flat black. :( )  


Your ES-1A looks in fine shape!   Keep us posted on your progress.

Regards,

Jim
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Tex
Senior Member
Tex
Joined: 27 Apr 2006
Posts: 840
Location: Texas - That's God's country to everyone else!
Expertise: Professional

Espresso: Bunn ES-1A (PID'd), Gaggia...
Grinder: Rancilio MD50
Vac Pot: Way too many vintage Silex...
Drip: Melitta Clarity
Roaster: TurboCrazy &...
Posted Mon Oct 2, 2006, 7:37am
Subject: Re: Bunn ES-1A rebuild
 

Here's the spec sheet from LocTite: http://tinyurl.com/l5gu7

I'm debating a full tear down just so I can get the exterior powder coated. There are now some nice candy & pearl finishes available & the finish is a bit tougher than paint. The shop where I have my stuff powder coated has a $140 minimum charge so I'll wait until I have a Gaggia Coffee with a bad finish to get it done. My other thought was to have the panels chrome or nickel plated, but that would make it look too much like one of those gussied-up home models.  ;)

 
Tex
--
http://www.tinyurl.com/mb4uj - My coffee pages.

http://www.tinyurl.com/2tnv87 - My 'Guidelines For Newbies' page.

http://www.tinyurl.com/2cr3e2 - I sell things for friends & neighbors here. Can I list something for you?

http://www.tinyurl.com/235dfr - BUG is Bunn User's Group (espresso)
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jimoncaffeine
Senior Member


Joined: 5 Oct 2005
Posts: 34
Location: Woodinville, WA
Expertise: I love coffee

Espresso: La Marzocco GS 1 group, La...
Grinder: Mazzer SJs, Rossi RR45s,...
Roaster: PID'ed Poppery 1, Behmor
Posted Mon Oct 2, 2006, 8:34am
Subject: Re: Bunn ES-1A rebuild
 

Cool!  Thanks for the link.

Powder coating sounds like a good option.  I'm partial to the industrial look myself, but Ferrari red or yellow would look sharp on the counter...  :)  

Have you checked out Eastwood for home kits?  I've considered this but would need to buy a used oven to dedicate to the process.  Still may go this route in the future.

Click Here (www.eastwoodco.com)

Regards,

Jim
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mikkelhaas
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mikkelhaas
Joined: 2 Jul 2004
Posts: 126
Location: Grand Rapids, MI
Expertise: I love coffee

Espresso: La Spaziale S1 Vivaldi II
Grinder: Mazzer Mini
Drip: Technivorm, Aeropress
Roaster: homemade drum roaster
Posted Sun Oct 8, 2006, 6:30am
Subject: Re: Bunn ES-1A rebuild
 

Robert,
I have a ES-2A sitting in my basement and you're welcome to use it for spare parts.  It's 220v, so not everything will be swappable, but maybe a few things will be.  If you need something, let me know and I'll see if I can find it for you.  

Mike
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Tex
Senior Member
Tex
Joined: 27 Apr 2006
Posts: 840
Location: Texas - That's God's country to everyone else!
Expertise: Professional

Espresso: Bunn ES-1A (PID'd), Gaggia...
Grinder: Rancilio MD50
Vac Pot: Way too many vintage Silex...
Drip: Melitta Clarity
Roaster: TurboCrazy &...
Posted Mon Oct 9, 2006, 6:08am
Subject: Re: Bunn ES-1A rebuild
 

Tell you what Jim, I'll buy the gun & powder if you'll do the spraying & cooking. I'll ship my machines to you sanded & prepped, you shoot 'em & send them back in their prepaid packaging. How's that sound? I just don't have a place to put an oven or I'd do it my self.

Tex

 
Tex
--
http://www.tinyurl.com/mb4uj - My coffee pages.

http://www.tinyurl.com/2tnv87 - My 'Guidelines For Newbies' page.

http://www.tinyurl.com/2cr3e2 - I sell things for friends & neighbors here. Can I list something for you?

http://www.tinyurl.com/235dfr - BUG is Bunn User's Group (espresso)
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Tex
Senior Member
Tex
Joined: 27 Apr 2006
Posts: 840
Location: Texas - That's God's country to everyone else!
Expertise: Professional

Espresso: Bunn ES-1A (PID'd), Gaggia...
Grinder: Rancilio MD50
Vac Pot: Way too many vintage Silex...
Drip: Melitta Clarity
Roaster: TurboCrazy &...
Posted Wed Oct 18, 2006, 5:44pm
Subject: Re: Bunn ES-1A rebuild
 

It's past time for an update.

No new pictures as everything still looks the same. All of my efforts are being directed toward rebuilding the working parts & looking into ways of improving on the original. First though, can someone explain to me why so many people are down on the Spanish espresso machines, such as Bunn, Futurmat, Mairali, Italcrem, Visacrem, & Gaggia? I've poked into Nuova Simonelli, La Pavoni, and other commercial machines and none look any different inside. The electronics look like the same Chinese fabrications & the quality of the forgings & castings looks identical. I'm assuming that negative comments about these machines are based on misinformation rather than facts.

OK, so what have I done so far? I rinsed out the boiler with a garden hose to get rid of as much loose mineral particles as I could.  I've received some parts from www.cafeparts.com, the silicone heating element gasket being the most important. After I reinstalled the element (with a healthy dose of LocTite RTV) I cranked up the power & gave it a first test. Almost as soon as I turned it on I was beaming, smiling ear to ear. No leaks, no shorts, and the pump worked. Boy did I get lucky.

After it came up to operating temperature I gave the programs a try & while they're not set for my needs all four of them functioned. I went through the different functions of the other levers & gauges. Both the hot water & steam valves didn't shut off properly & the anti-siphon valve remained open. I put a blank filter basket in a portafilter & tested the 3-way solenoid, which is OK - but the group gasket had to be replaced. No big deal, I have extras on hand.

So, I had work to do on the machine but it seemed to be all very minor & easily dealt with. First I pulled the anti-siphon valve & after disassembling it, it went into a hot bath of citric acid solution. When it was spic & span I reassembled it & put it back int the boiler. Next I pulled the hot water & steam valves for a look see. The internals were a bit grungy but I've seen much worse that didn't leak. After reassembling them I hooked them up for a bench pressure test, which they promptly failed. Now what? I pulled them again for another look see & they looked too good to be the problem, but just in case I replaced all of the o-rings before reassembling & retesting them. Guess what? Same results; they wouldn't shut completely off.

Getting bit hot under the collar I remembered the all too often uttered, agonizingly appropriate, saying of an old ROTC advisor from my Aggie years, "When all else fails Cadet, read the blinkin' directions." I had just gotten a packet of information from Bunn that contained everything you'd ever want to know about the ES-1A. After thumbing through the stack I found the blow up of the valves. Hah! I had been doing what I always do - put everything back the way I took it off. But guess what? The previous technician put the compression spring on the wrong end of the valve plunger, resulting in too little pressure on the valve seat to hold it closed. After putting it back together according to the drawings the bench pressure test went off just fine!

So, with all of the initial problems resolved I cranked up the machine & tried a few shots. No leaks & everything seemed to be working correctly. I couldn't get adjustments on the pump & pstat to register on the pressure gauge, so I'll be ordering a new one this week. Other than that I've just been pulling shot after shot trying to pin point any flaws needing fixing before I button it back up. After I install the new pressure gauge I'll be better able to evaluate the health of the pump & pstat. If they're OK I may stop there, reassemble everything, & install it in my kitchen. I still plan to powder coat it but that can wait. As can the idea I'm toying with of installing a PID. The PID would make the boiler temperature a lot more stable than the pstat is capable of. But there are some technical issues I have to work out such as where to put the thermocouple (dead center in the middle of the boiler would be optimum, but how to accomplish this?).

That's where things stand tonight. Maybe next week I'll have it buttoned up & pulling shots in my kitchen. If so I'll post a link to some pictures for those who'd like to see them.

Ciao!
Robert (Don't you just love good Bunns?) Harmon
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jimoncaffeine
Senior Member


Joined: 5 Oct 2005
Posts: 34
Location: Woodinville, WA
Expertise: I love coffee

Espresso: La Marzocco GS 1 group, La...
Grinder: Mazzer SJs, Rossi RR45s,...
Roaster: PID'ed Poppery 1, Behmor
Posted Wed Oct 18, 2006, 8:41pm
Subject: Re: Bunn ES-1A rebuild
 

Robert,

Congratulations on the progress!  Not ready to evict a vehicle from my garage to start a powder coating business...  Yet... ;)

Sounds like you are golden if you've gotten as far as you have.  I recently put a pid on my new (to me) la san marco machine.  I used a surface mount tc attached to the boiler via a large hose clamp that is used to locate the boiler to the machine.  While I am sure a tc directly in the water would be better it seems to work surprisingly well as is.   If I were to put one in the water, on my machine the most logical place to do it would be to t-off the boiler safety valve, turn it on its side and get a custom length tc with a swage lock on the end.  Currently, total cost of the ebay pid and ssr was $35 and the surface mount thermocouple was about $15.  It was pretty easy to setup as well.  The boiler stays at exactly the temp I set it.  I hooked it up in parallel with the pstat so that I could have the redundancy and that if the steam pressure dropped too far before the (external) boiler temp was reduced it would activate the element.  I have the pstat set to about .9 bar and current boiler temp is at 234 degrees.  The only time the pstat activates the element is when I steam or when the autofill circuit is activated.

Can't comment on the Spanish Machines since I've never worked on one or used one.

I'd wish you luck, but then you've already got that! :)

Keep us posted.

Jim
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