good morning YouTube we're looking at the back side of my Breville barista express coffee machine
this is where the tank sits and I've already got that loosened up here so I've had to open this
machine up again I'm thinking I have a problem with low pressure out of the pump and I also
have a problem up above here on the hot water and steam valve on the side there so before I get into
the repairs I've been looking around inside here both inside the machine and then I've also looked
at the part diagrams on the replacement parts web site the diagrams themselves aren't that useful
from what I found but the parts descriptions and photos are actually somewhat informative but I
think I've figured out how the water flows through this machine in the various modes and I figured I
would take a look at that this is the hose that comes out of that valve that's on the tank there
so the water comes in here I believe that's a check valve at the bottom there and then this
round device here with the three wires plugged in a flow meter so I believe this probably has
power ground and a signal your typical three wire sensor and this device here measures how
much water is flowing in from the tank and then out to the bottom of the pump that's right here
and I imagine what they use that for is number one for the one cup or two cup brewing cycle so
when you program in the size of a one cup shot it knows how much water to send through there
and then I think they probably also use this for the clean me light there's likely a little
vein inside of this that spins as the water flows through and it probably puts out some pulses that
go out over this wire and then into the processor board that's behind here so they probably use that
for the clean me light as well so many pulses of the meter turned the clean me light on this hose
goes out here's your pump the inlet of the pump is down there on the bottom then the pump comes
up here this is the output of the pump and then right here this is what they call their safety
valve or overpressure valve so it's kind of like a tea fitting it's open up this way so the water
normally just flows up and out but if the pressure exceeds probably around 15 bar it will come out
this way and then dump into this tank over here or what they call the diffuser so before when I first
looked at that I thought this was on the inlet side but this is actually where they dump excess
water and aim and pressure and you can see this this thing is sort of shaped like a car muffler
inside there's all these baffles and I guess you get some of the coffee residue that gets down in
there as well if the pressure is exceeded that goes right in here so this hose on the far end
comes out of the solenoid block and dumps in there and then this Center hose comes off of the manual
hot water and steam valve and that's the overflow or the the exhaust port on this valve they call
this the diffuser so this basically dissipates the high pressure and then right underneath here my
finger is just on the little rubber pipe that comes out of the bottom of this diffuser into
your drip tray that's where your excess hot water and steam comes out of the diffusers and so every
time you finish a brewing cycle or especially if you run the hot water or steam and you turn this
from hot water back to standby you'll hear a big woosh and that's the water and steam coming into
this diffuser and then you'll see steam coming up out of the grilles on your drip tray so that's
how that works so that's the overpressure side of things so like I say here's the normal flow
comes up out of the pump up through this hose and it comes in to the top of what's called the
thermal coil so inside of this thermal coil is coiled up tubing if we look on the top here it
says 120 volt 1600 watts so this is 1600 watt one point six kilowatt heater and of course if you're
outside the US you'll have a 240 volt heater and you'll have 240 volt solenoids and a 240
volt pump so the pump only pumps cold water so it comes in cold goes up here into the coil probably
makes a number of loops and then it comes out over here so this hose here comes out of the
bottom of the thermal coil and into this elbow that goes into the solenoid block here so this
is what they call the 2/3 way and I guess what that means is that there's three ports you've
got one port on that side you've got a port on that side and then you've got a port on top
so there's three ports and then it's a two-way valve so if this solenoid is off the hot water
comes out of the coil and comes up through here and that goes over to your hot water steam valve
here this right here is your hot water outlet in fact if I put my finger down there just underneath
that's where the hot water comes out and that's right below this tube and then the steam wand
comes out right down below here's this tube is the diffuser or the dump lines so on this valve when
you switch from hot water or steam back to standby it dumps all the pressure out of this tube right
here and then I guess the way this valve works it's a mechanical valve so there's no solenoid
involved but you can see there's a little limit switch there and there's one down there yeah a
couple of wires up there off the top that run down there and they probably go back into the control
board here those switches tell you there is steam if that switch is closed and then when it's steam
mode it tells the thermal coil to heat up a little bit hotter to superheat the water and then in the
water comes out here and then flashes to steam in your steam wand and then when you release it the
pressure gets released down into the diffuser and then out into the drip tray and likewise if you're
in hot water mode this bottom switch closes right there and then it's water up through this one and
out your hot water so anyway that is the hot water steam side now if this solenoid is turned on this
upper port blocks but the lower port passes water through and then it comes out of this line and
this line I thought went into the thermal coil but it actually goes into the group head down here so
this is where your espresso water gets pumped and it goes in here and then down through the
filter basket and into your cup and then about the only other thing you've got up here here's your
pressure gage so there's a hose that comes off of the top of the group head and then over and down
to the gage what's the back of the gage that that hose plugs into to brew your espresso you turn on
the pump you turn this solenoid on the water comes up here heats the water it comes out here it goes
through the base of this valve it comes up here and and runs down into your culture basket and
comes out the bottom and then when the brewing cycle stops this solenoid turns on and lets any
excess pressure go out here and drain down into the diffuser again so this is critter drain valve
and then this one is switching between hot water steam and espresso yeah so now it finally makes
sense why if this valve was buzzing which is why I replaced it it wasn't able to fully turn
on so it left both sides open so this side here was open to the group head but it hadn't closed
this hose so the flow was splitting between this hose and this hose and what happens is if your
hot water and steam valve is in the standby position this incoming hose feeds directly
into the exhaust hose so what it was doing was bleeding awful some or all of the pressure out
of the pump was getting sucked through here and then down through there because this valve here
wasn't fully closing off the top pork so that's why this valve is really critical because as I
showed you in the previous video this valve has a some metallic slug inside when it's down it plugs
the bottom port within when it's up on the top it plugs this top port which stops water from going
up here but if this valve is buzzing or it can't quite move fully then it's trying to send water
here which needs a lot of pressure or send water here that just comes straight down the drain so
actually in my case this valve was probably okay but it was this valve that was causing problem but
yeah anyway I think that's how this works but I want to actually see for sure if that makes sense
that picked up a couple of these hundred 20 volt indicator lights and I'll hook these indicator
lights up in parallel with the solenoid so if the solenoid turns on the indicator light turns
on and I'm gonna put these in the cover towards the back and I'm just gonna leave them in there
and then I'll be able to see if this light turns on that solenoid is on and if that light is on
this solenoid is on and I'll be able to see how those solenoids work and having some blinking
lights on there's good things so anyway that's one of my future projects so stay tuned to one of the
next videos and I'll show you putting these in and we'll see if my hypothesis on how these solenoids
work is correct the next project I have is I think might pump or the safety valve might be defective
because I've been noticing my pump output or the pressure output on the gauge has been falling and
it's almost non-existent now so either the pump is bad and the pump is actually rebuildable but
I figure I would just change the pump out so I picked up a new pump and a new safety valve so
I want to just put that in right away and then I'll take this one out and we'll try testing
the pump and I'll see if I can figure out some way to test the valve and then you might have noticed
that hose that's another project because I saw some signs of water dripping you can see there's
a lot of white calcium or limescale built up here and like down here there's some and so there was
signs of water leaking out of this manual valve I literally just touched this hose and it was
loose and that was inside of there that was the original hose barb that used to be part of that
casting right there and it was stuck inside of the end of the hose so I got that out of there
you can see how corroded it is I don't it was a defect in the casting because the outer wall is
just paper-thin and there's like nothing inside of there but anyway I need to fix that because that's
just a direct water leak if there's any pressure in this line it goes up here and right out there
and this drips down inside the machine we've got to repair that we've got to replace the pump and
then when I'm putting it back together I'll put some blinking lights in there got a couple of
projects lined up so anyway I hope you enjoyed that look inside of one of these machines do
you have any other questions post up in the comment section below you like content like
this subscribe to the channel link in the lower right corner and as always thanks for watching