Recently drained and prepped my Maxi to loan out, but plans changed. After about a month of it sitting, unplugged and dry, I plugged it back in, filled the boiler and reservoir, and turned it on. Pump engages, a little steam spits out of the grouphead and that's it. I turn off the pump after about 5 seconds, wait 5 more seconds, then turn the pump back on. Repeat this cycle 3-4 times, figuring that the HX just needs to fill up, but after 4x, I'm seeing the same behavior.

The heating element engages, the boiler heats up, comes to temperature then clicks off just as it should. Steaming is fine. That eliminates anything directly related to the boiler.

After doing some digging around, most of the other posts regarding this type of issue point at a blockage of some type, so my game plan is to follow the flow of water from the reservoir, checking at each connection point for possible blockages or kinks. This has happened a couple of times now, and IIRC each time it was due to the machine being emptied in preparation for transport. Oddly enough, it usually resolved itself after being filled and left alone for a day or so. I'll be investigating more this weekend, but would appreciate any preliminary thoughts or opinions on what to check.

Sherman, I've seen very similar behavior with both of my Oly pump machines. Is the pump noise far louder than normal? It was for me, and like you, I experienced this after the machine had been stored for a while, or the reservoir had been removed for a while. Though I didn't follow any set routine, it seemed that each time, cycling the brew-switch on for a couple seconds, then off, waiting maybe 10-20 seconds, then doing the same again did it. I kind of think I was priming the pump.

Hmm, wonder if there's an bubble, or air-gap, that needs to be cleared...

*le sigh*

And just like that, we're in business. To the best of my knowledge (and RAS' reports), the Olympia pump machines need to "rest". I don't have a wonderful unified theory that explains it, but maybe it _is_ an air bubble or some other such interference that goes away after a period of time.

RAS - thanks for the confirmation. During my next service interval, I'm going to dig a little deeper into the plumbing and see if I can discern a reason for this behavior. At least it's consistent.

Both of mine are Fluid-o-Tech. I believe that's what Sherman is dealing with as well. Good news is that they have an almost-ideal pressure profile where the fact that they don't have an OPV is less of an issue.

The bubble-trap sounds intriguing - thanks Jim. I'll look into it.

Yep. Fluid-o-Tech here too. I just ran the reservoir dry on accident, and noticed the exact same behavior again. RAS - I'll be curious to see what you dig up before I embark on a bubble trap. For now, I just have to remember to refill my reservoir at the end of each session.

Jim - could you provide a link to this "bubble trap" or, is this what you are referring to -
http://www.chriscoffee.com/products/home/isomacparts/airreleasevalve ?

Yes, they are identical except for material. Installed directly into the discharge snout with a -010 o-ring. They will work with the FOT pump but may not physically fit into the machine's hydraulic layout.

Thanks for the links. I'm looking at the part and trying to understand how this all fits together. From what I can tell, this would attach to the pump intake:

(reservoir)
    |
(valve) --> return to reservoir/tray
    |
(pump)
    |
(HX circuit)


Which means that I'd have to add a hose and return to the reservoir, or drill/tap/tee into the tray. Maybe I could tee at the 3-way valve, so I don't have to drill another hole?