in the shop today

New patient - an old Olympia Cremina needs TLC

This Astra Gourmet has a halting water flow.

Still trouble shooting the hydraulics.

Update - Interesting, this is a Pour Over machine so it does not have line pressure from the water source. The water is pumped into the system - eventually to the group to make espresso & when water is not being pumped a check valve (one way valve) prevents water from being pushed by pressure (heated water) back towards the pump. The one way valve has failed allowing the HX water to be drawn back into the pump & tank. This results in a dry HX - and when the barista tries to pull a shot - they get air instead of water for a shot or 2. Solution - replace check valve.

astoria - back from the dead - just in time for halloween

New tech, John just gave this Astoria a minor rehab.

looks good to go!

HX rotary pump, HX vibe pump, double boiler rotary

This week brought 3 machines for repair in the shop that demonstrate 3 distinct choices for home espresso machines.

The Double boiler was an older Marzocco GS3. This came in with a bad group solenoid and needing adjustment to the expansion valve. Otherwise it is in good shape. The 2 boilers provide steam from the large rear boiler and dedicated espresso from the front boiler. The front boiler is thermostatically controlled at the front mounted led pad. Brew temp is very consistent and predictable.

Heat Exchanger (HX) machines use a different approach to heating. They heat one large boiler for steam and run the espresso supply water through the very hot water in a tube. The conductive energy heats the espresso water. The result is that you do get copious steam on demand and lower temp water for espresso making. The water temp in the HX for espresso is not as predictable as in the double boiler. With an E61 group the water is siphoned & circulated back into the HX system which does provide some temp stability. The HX can be fairly easily mastered so that the operator can produce consistent & great shots. The other choice is Vibe or Rotary pump. The Rotary pump is quiet and extremely reliable. It produces excellent pressure stability. Most Rotary units require plumb-in water. The vibe pumps work well, though they are noisy and have a generally shorter life (though they can last a decade or longer).

These HX units are both Quick Mill units. The Vetrano (LEFT) is a Rotary plumb-in model that had some scale problems throughout the hydraulics. The Andreja Premium (RIGHT) is a Vibe pump model with pour over water tank. This one had a little leak.

Marzocco GB5 PM & steam boiler refill issue

Marzocco GB5

I had recently reminded this small cafe that the GB5 was due for a PM and we had planned on making an appointment... Then the steam boiler was shutting down and the LED read 'Steam Boiler Empty." The GB5 has 2 level sensors - one to alert the unit to refill the steam boiler when it is depleted from steam or hot water use & a second sensor to shut off the heater if the boiler is not refilling. If the second sensor is activated, the LED reads "Empty" though the boiler is still far from empty. If the system works as designed it will avert a much more expensive Heating Element Replacement.

As part of a Preventative Maintenance Service we always remove the sensors and inspect, clean or replace appropriately. In this case the sensors were badly fouled with thick, dark, very hard crust so replacement was the best option. Otherwise the PM was typical and we recommend more frequent change out of water filters.

Seeking new Technician

Great Infusions is seeking a self-motivated, highly organized individual to support our service department. You will be responsible for for the installation and service of commercial coffee and espresso equipment, preventive maintenance and emergency on-site technical support. Qualified candidates should have electrical/mechanical DMM mastery and trouble shooting experience. Well organized & tight record keeping a must. Clean DMV & reliable transportation a must.


Email your resume to info(at)greatinfusions.com

office pn. 831-458-3568

Brewtus by Expobar

This is the interior of an Expobar Brewtus. The Brewtus is a double boiler espresso machine. The rear boiler - on the left - is steam and the front boiler is for coffee. The steam boiler is controlled by pressure stat and the front boiler is thermostatically controlled with LED control. As with past Expobar units, this had a few components that are less reliable than most other makes. The Ceme brand vibe pump seems to have a poor record - replace them pretty often. The pressure stat on this unit was bad and it is a cheaper part than other makes. This machine had virtually no scale - so the part died prematurely. This unit also had a worn E61 gasket housing that prevented backflushing and pressure release after shot making. The maker leaves the plastic laser tape lining the stainless inside of the box - why? It had burnt/curled in areas and was loosening in others - funky.

Olympia Cremina

I serviced a Cremina with a bad pressure stat. The micro-switch was fine but the proprietary membrane/housing was sticking, causing overheating.

Instead of importing the new (expensive) part from Switzerland, I replaced the brass housing with a copper tube and a MATER p-stat. The $40 part worked well... When set to disengage just shy of 1 bar it would re-engage at .08 bar.

Picture shows the new installed MATER and at bottom the original Cremina stat.