Hello All,

I've got a GB5 that from 2007. It's only had two years use out of it. The past few days my steam boiler pressure is only resting around 1 and it's been dropping to below .5 from time to time. It'll go back up gradually but I feel that something is a bit off.

Has anyone else experienced this and is there any idea as to what is causing it?

Any thoughts would be helpful.



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Are you pulling a lot of water off of the hot water spout?

we are not. we don't use the spout much at all. i called la marzocco and they are sending out a new pressure switch to see if that is the issue. i hope it is. i'll post back on here if it fixes it.


Pressure switch would be my first thought too... and is the cheapest and easiest of the likely possibilities.

Other candidates farther down on my list are the contactor (giant relay) or a heating element issue. If you'd dropped a coil on your heater you'd be under-powered, which would cause delays in responding... which would show up as an inability to maintain pressure under periods of high use. Contactor failure looks alot like pressure switch failure - delays in  turning on the element.

Other, less likely possibilities include a substantial steam leak, a malfunctioning pressure gage, or a scale obstruction somewhere.

Have you had any kind of electrical power issues in your building lately? Any other equipment start acting funny at the same time? I replaced a contactor at a customer a couple of months ago... turns out that a squirrel had decided to explore the area where the transformers were in the building. The resulting power surge smoked a couple of refrigerators and melted this contactor - resulting in no heat.

Hope that helps. Good luck, and let us know what happens.

well, here's hoping it's just the pressure switch! We've had a blender go out and had a voltage issue on our front reach in fridge. those could all add up to a bit of trouble. it's worth checking into.

thanks for the tip.

I would bet on the P-stat as well.

I believe the GB/5 had Solid State Relays.  They fail less often the mechanical contactors. And it general are more tolerant of power surges.   And the heating element is a single coil. The wattage should be printed on the info plate on the side of the machine or underneath the front (can't remember ATM).  If not, the element is stamped on the end, it's kinda  small.  You should ohm out the element while you're in there.  Also check the line to the pressure switch.  Make sure it's not plugged.     

How's your water?  

Oh, had I've had a squirrel incident as well.  Took out one leg of a three phase panel.  Though, only one espresso machine and the RTU's where tied to that leg, so it seemed like a machine issue.  Machine would sit there, display on, but as soon as you tried to run it, it would reboot.  Figured it out just as the HVAC tech showed up.  Made for an expensive call.  

the GB-5 has a p-stat and a separate contractor. you can adjust the p-stat, it is a round unit in the back left corner. with the power completely off at the breaker, you can check the contactor to see if the contacts are fried. if your not electrical savy, call a tech as its 220! the GB 5 has 2 seperate probes that control the water level and no sight glass so its a little harder to tell if it is over filling the steam boiler. that is a slight possibility, as well as the element going bad. I would suspect the p-stat and/or the contactor first.

BTW, I change my contactor out for a SSR as I used mine at home and the  contactor relay is very loud as it clanks on.


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