# DB buzzing solenoid



## ajohn (Sep 23, 2017)

I've been getting signs of this so thought take it apart and have a look. It's pretty easy to do. It would be a good idea to have a magnetic PH2 screwdriver around. I also replaced the cable clip on the exhaust outlet - big pipe on the top - with an 8mm fuel line pipe clip. Nothing fancy just the single wire type.

Unplug - important as it has a clock in it the solenoids are live even when the machine is off. Always worth checking on anything that doesn't have an on off switch.

Cut the clip off and ease the exhaust pipe away from the fitting

Look carefully at the earth lead spade connector. The is a little bit that "sticks out" of the receptacle just past the end of the blade on the solenoid. That needs to be pressed down to take the connector off. It's more like a short bump. The mains connectors are insulate but if gripped with electrical pliers over these bumps they can be eased off. No chance without.

Slacken the nut on top of the solenoid off a little if needed to ease screw driver access to the fixing screws and remove them.

Remove it. I marked the base with a marker pen on the side adjacent to the markings on the solenoid coil - just in case but other things mean it can only go on one way.

Look under the base. There are 2 plastic discs with low diameter tubes in them. Remove them. I used tweezers on the tubes. Might not be a good idea to press them too far in playing about but the can be levered out with a pin etc if not enough to grasp.

Remove the nut on top of the solenoid completely. When this is replaced don't do it up too tight. There is a washer under the coil and the nut has a flange which fits into the coil. Lift off the coil.

I then held the square base in a small vice. Other things could be used. Then undo the nut directly over the base. There is a plastic ring between the valve stem and the base. This needs to be done up firmly when it's refitted.

Lift off the valve stem. A plunger and spring will be left in the base.

Have a good look around for grot etc, I may have found a tiny trace at the ends of the solenoid plunger. So little hard to be sure.

That's about it other than getting it all back together so reassemble the lot.

Take the plastic discs and tubes. Put the tubes in place and press them in to their flanged ends.

Then put these back into the machine - tubes go into the tiny holes.

Then put the valve back in place feeling the discs into the 2 depressions.

Then refit the screws and exhaust pipe. Tighten the screws cylinder head style diagonally a bit on each side until they are firmly down.

I think mine was rather loose as it tilted as soon as I undid 2 of the screws. There was also a bit of discolouration around one of the holes in the casting in the machine. Could be that they shouldn't be clamped firmly down on the base but that would need checking with feeler gauges - dubious, @DavecUK  may tell you this is an odd way of sealing them. Usually there would be O rings in the depression in the base. I suspect that the tubes are for metering and lo the 3 way exhaust action seems to be better now but just based on one shot. This may be down to pressing the tubes in until the flange on them was against the plastic discs.

No buzz now. There is during infusion, probably down to the pump.

The other reason could be the coil. It is probably possible to buy those separately without too much of a problem. All of the bits in solenoids are available for some makes.

John

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## ajohn (Sep 23, 2017)

Looks like the 2 little tubes may save me trying to add a restriction to the 3 way when it dumps water at the end of a shot as this is what they would appear to be for.

Refitting them has done nothing about pucks sticking to the shower screen out of a certain range of fill weights but I can now see where I am working by looking at the top of the puck as it's nice and flat and smooth. Before I was getting odd flakes being lifted off and signs of the surface being a little broken up. The smoothness says nice things about Niche now it's more run in.

 Problems though. I now know that the puck was hitting the shower screen when it expands. So dropped the dose by 1/2g tuned for my usual ratio and don't like the taste as much as I did. Other than the rim, down to the shower screen I'm using it didn't hit the screen. If I retuned as it tastes a bit over extracted it'll probably be weak so guess I'll find my previous dose was correct and the overfill isn't sufficient to weaken the drink. I had to drop the dose by 1/2g when I switched to Niche from a Mini. It gave a remarkable increase in taste. Same drop on the Mini didn't.

John

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## urbanbumpkin (Jan 30, 2013)

ajohn said:


> I've been getting signs of this so thought take it apart and have a look. It's pretty easy to do. It would be a good idea to have a magnetic PH2 screwdriver around. I also replaced the cable clip on the exhaust outlet - big pipe on the top - with an 8mm fuel line pipe clip. Nothing fancy just the single wire type.
> Unplug - important as it has a clock in it the solenoids are live even when the machine is off. Always worth checking on anything that doesn't have an on off switch.
> Cut the clip off and ease the exhaust pipe away from the fitting
> Look carefully at the earth lead spade connector. The is a little bit that "sticks out" of the receptacle just past the end of the blade on the solenoid. That needs to be pressed down to take the connector off. It's more like a short bump. The mains connectors are insulate but if gripped with electrical pliers over these bumps they can be eased off. No chance without.
> ...


Did you take any photos?

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## ajohn (Sep 23, 2017)

Sorry no need as it's so simple. One other way is to forget removing the spade connectors from the solenoid as that is awkward . Just undo the nut on top of the coil and it can be lifted off and then the rest removed and dismantled as mentioned. When replacing the nut on top of the coil that keeps it in place don't do it up too tight. It's more a case of nipping it up rather than serious tightening.

It's very likely that any solenoid in any machine can be handled the same way. Some cheopo's use a clip to secure the coil rather than a nut.

Similar solenoids to the ones Sage use are used in many machines. Until I actually fit one the only difference looks to be that Sage have a hose barb at the top where as most solenoids that are easily available use a flared tube and nut arrangement. These also use a brass base where as Sage use a stainless one - those seem to cost an arm and a leg for the other types of connection - if they can be found.

I'd guess the answer really to buzzing solenoids is more frequent back flushing. I vaguely remember a certain gent mentioning weekly. I have been a bit lax on that.

John

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## urbanbumpkin (Jan 30, 2013)

Apologies if it not obvious. Which one is the coil?









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## ajohn (Sep 23, 2017)

This is a photo of a similar part. The Sage one has a hose tail instead of a flared pipe union on the top. On Sage a plastic tube is just pushed onto the hose tail. It's the outlet for the 3 way action.









John

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## ajohn (Sep 23, 2017)

I'm pretty sure I have found where the fine sludge came from. But also it was due a descale and I noticed that the brew boiler wasn't draining reliably. The solenoid buzz interfered with the last descale. So

Initially I stuck to when the machine told me to back flush and when to descale set by the test strip.

I decided to back flush more often even though the shower screen I use seems to limit what goes back into the machine. Just seemed to be a good idea.

I noticed that after descaling that there was still loud bubbling noises so did 2 on the trot also because I wondered if the brew boiler had really drained on the first one. That cured the bubbling noises and steam was available earlier. More less at the same time brew was ready rather than a bit after.

I can't be sure I have always fully drained the brew boiler so in future will empty the drip tray after draining the steam boiler. Or try doing it the other way round as it's easy to see that steam has drained.

When their engineers say descale once a month they may be correct. I've seen mention of every 2 months on a USA site.

The sludge I cleaned out of the solenoid was very fine and pale in colour and very little of it. It could just be wiped off. Everything in the machine including the solenoid gets pretty hot so any standing water in it will evaporate. I'm going to do a daily clean water back flush with an empty pressurised basket to see if that helps. It took over 12 months to get like this and a lot of shots and heating cycles - something getting up to 1700 of them.

B'ham gets very soft water but as a man on here once mentioned they sometimes add water from other sources but anytime i have tested it it's always been low.

Need to take some photo's before dealing with a draining a problem brew boiler.

John

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## DavecUK (Aug 6, 2013)

If it's buzzing even after solenoid disassembly and cleaning, then you need to replace the solenoid as the shading coil is probably not working/damaged. Often though the fault is because the plunger doesn't seat close enough to the shading coil (dirt damage etc..) and then the spring pressure causes it to chatter as the collapsing AC field only induces a relatively small force in the shading coil. The base of the plunger not seating properly makes this a little too far away to "grab" sometimes at field collapse.


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## ajohn (Sep 23, 2017)

I'ts not buzzing any more but may be able to replace it with a Parker. F1 time so off for a while.

John

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## ajohn (Sep 23, 2017)

If the brew boiler doesn't drain after their suggested *longer* push of the 1 cup button a few things are needed - bonnet stay for the lid.  This one is about 35cm long. Follow the manual to descale. A brief push of the one cup moves to the next stage - boiler fill, heating and a 20min descale.









Place in a mess. Just had some plastering done were the machine goes. It would be wise to have some BS 007 sized silicone O rings about.









The brew boiler is central. The 2 front connections to it are level probes, larger dia and 009 O rings. They seem to use one for negative and the other for positive and sense current flow between them rather than the actual boiler forming one side. Remove one of the rear 2 two clips, left is probably favourite and pull out the pipe. The boiler should then drain. If not something is blocked. The O ring will probably stay in. Rather then simply pushing the pipe back in as I did damaging it prise it out with say a cocktail stick. Best fit new ring really. Fit the ring and push the pipe back in fairly firmly and refit the clip. The rings just slide on. I then moved the pipe up and down gently to make sure it was seated well but probably a waste of time. Looks like they use diameter to seal. A bit of water on the ring might be a good idea. Then tap the one cup button to fill the tank etc.

Still not entirely sure why it wouldn't drain. Shouldn't be sludge in the 3 way solenoid now but may be down to airlocks in the 3 way drain pipe to the drip tray.









Something else where water sits that will evaporate.  I may have rooted it against the ptfe pipe when I cleaned the solenoid so have now switched it to the other side. Not sure if the entire pipe can be pulled out. Sage may have fixed the end in the drip tray some how. There is a lot of attention to detail in them in all sorts of areas - like the stainless spring to make sure the pipe doesn't kink. I'm going to try a straw brush to clean that but just unclipping the pipe from the solenoid may have allowed the boiler to drain  wouldn't surprise me actually as I didn't check for water in it. I removed the tie wrap Sage use at the solenoid end and replaced with one of the clips from this kit. Might need other sizes elsewhere

https://www.amazon.co.uk/gp/product/B07G2YRL9J/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

This video shows how they used to have to be descaled. Interesting that the triac board is in the same place leaving space to add a grinder later. No need to remove the back panel but the prop is a good idea to prevent straining cables. Some parts of the machine are live when it's plugged into power so be careful with the solenoid and probably the heaters. The red item in the shot above is one side of a heater.






I'm not bothered about items being live providing I know where they are. It's pretty obvious which ones may be in this machine. The solenoid connections are insulated so no problems with those - obviously turn off at the socket if that is going to be removed.

I find the inside amazing, especially the wiring. Chinese labour must be incredibly cheap. I'd suspect they might update at some point and start using other methods as some of the wiring could be done a hell of a lot quicker. The button wiring reminds me of car dashboard wiring nightmares.

John

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## ajohn (Sep 23, 2017)

Another BES900 video. The part he is replacing has gone. Looks like it's solid metal now attached from below.






Their machines do change over time.  Only when they need to.

The 3 way drain pipe I menioned is securely attached at the far end. Dedicated fitting to take 2 drain pipes held in place with screws. Pipes fastened onto it with cable ties. Long reach screwdriver could reach - a magnetic bit would be a very good idea. Their screws often aren't very magnetic.

John

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