Customer issue: Why do the pump and respective brew pressure gauge oscillate during an espresso extraction on traditional espresso machines (not super automatics)? This is typically for vibration pump espresso machines, not rotary ones.
The usual suspect is the grind fineness not being consistent or coffee beans that are too fresh (not degassed, but to rule out the espresso machine, the following should be performed:
- On a machine that is capable of backflushing (not all espresso machines are capable and skip this step if not), insert a blind basket in the portafilter or a blind insert into the 2-cup basket, and insert the portafilter into the grouphead. Engage the pump for 30-40 seconds, If there is no oscillation, then it is the grinder, beans, or grind fineness that is the issue. If it continues, proceed to Step 2.
- If there is no water softener in the tank, proceed to Step 3. If the pump oscillates like in Step 1, remove any water softener. Perform Step 1 again. If it doesn’t oscillate, then the water softener is clogged and usually needs replacement. If it continues, proceed to Step 3.
- Remove the water from the tank, fill it with a descaling solution, and run 8-12 ounces of solution through the grouphead without the portafilter. Perform a backflush routine (without backflush detergent as there is a descaling solution in the boiler and grouphead). Allow to sit for 4-8 hours. Remove the solution and rinse the tank. Then fill the tank with plain water. Run 8-12 ounces of water through the grouphead. Perform Step 1. If there is no oscillation, then you cleared the pathway causing the oscillation. If it still oscillates, proceed to Step 4.
- When using the blind filter or insert, check the power light to see if it dims. If it does dim, then the power supply may be an issue. If there is no dimming, then proceed to step 5.
- The pump at this point will need replacement. Please use the parts diagrams to find the correct part, and search by part number on our website for availability, pricing, and ordering.