The temp of my Vetrano brew head is well below the expected idling temp. It is only at around 134 F after being on for 2 hours. I had taken off the mushroom because the temp was low at 194 F. Now it won't get higher. The mushroom itself had no significant deposits. Did some back flushes to perhaps purge any air in the system.

Yesterday the machine likely had a fill solenoid failure and leaked from the top of the boiler. I checked the solenoid valve and it was clean. Restarted the machine with the above results. Incidently, I replaced the fill solenoid earlier this year. The e61 thermometer is new this year and just checked it as well. It is within 1 F in an ice bath and boiling water.

Ideas?

Just trying to bump this thread to see if I can get any ideas before calling service at Chris Coffee on Monday. I pulled the mushroom again to make sure that there werre no obvious problems. I did notice some scale at the thermosyphon return tube inlet, but seemingly not enough to prevent circulation.



One thing to add to my initial post is that the boiler gets up to pressure, 1.2 bar, in several minutes as usual.

Dave

Is there a typo in your first post? Do you mean 194 in both cases?

Do you know what your inlet water pressure is? A very reasonable value is around 35 psi (~2.50 bar).

Disable the boiler's heating element and syphon a few cups of water out of the boiler using the steam valve connection at the boiler. Turn the machine back on and measure the level of water in the boiler using a wooden dowel "dipstick" through that steam valve tubing connection. A reasonable number is about 4.50" as measured from the bottom of the boiler.

If the machine still only gets to ~194 after all of this, flow a few ounces of water from the group? Does the temperature now start to climb? This would indicate a leaking brew valve.

The OPV on Vetrano is a thermal expansion valve . . . is there a constant drip from this valve when the machine is warmed up? If so, it is time to replace the internal seal in the OPV.

Not a typo. The machine is group head is now 107 F and goes up to 140-150 tops when flushing. Inlet water pressure is 2 bar.

The opv seat has been replaced when there was a flooding drip 1-2 years ago. No drip at all now. Come to think of it, I have not seen a single drip. I am getting flow from the drain side of the three way group with the pre infusion position of the lever and also after shutting off the brew lever without a portafilter in.

Before I disassemble anything, how would the water level affect the group head temp?

I would think that a brew head temp that low indicate something obvious, just not to me

Before I disassemble anything, how would the water level affect the group head temp?

The overall Heat Transfer Coefficient (U) for a Steam-Copper-Water "system" is 205 Btu/ft2-hr-F or 1160 W/m2-K whereas the overall Heat Transfer Coefficient (U) for a Water-Copper-Water "system" is 60 to 80 Btu/ft2-hr-F or 340-455 W/m2-K. So, as water levels rise, a lesser area of the heat exchanger is available to the steam side and a lesser amount of heat is transferred . . . hence lower grouphead temps.

I am getting flow from the drain side of the three way group with the pre infusion position of the lever and also after shutting off the brew lever without a portafilter in.

The only time you can get any preinfusion is with the lever slightly elevated from the neutral position but without engaging the pump switch. There should be NO FLOW from the drain side of the group with the lever in the neutral position.

When you lift the lever to engage the pump and flow water from the grouphead, you are (obviously) filling the cam pocket area of the group. When you move the lever to the exhaust position, you should get only a few dribbles from the exhaust port . . . certainly I do with Anita.

Disconnect the pump electrically and lift the lever into the brew position. If there is a delay in getting water from the grouphead, this indicates that the brew valve is leaking and hence the thermosyphon stall.

I disconnected the pump brew switch at the lever. When in the brew position, flow is through the group as expected. When only moved into the halfway preinfusion position, quite a bit of water flows from the drain side of group at first, then transitions to the group head.

So......a leaky brew valve?

Dave

If lifting the brew lever to the "mid position" to open brew valve causes water comes out of the "exhaust" of the group then that is a problem that indicates that a rebuild of the group is in order. On my website, see: How-To 19 - Overhauling and Lubricating the E-61 Group

Thanks Randy and Eric.

I will order the kit and hopefully have this resolved by this time next week.

Dave

So......a leaky brew valve?

At the very minimum.

I agree with what Randy G. said EXCEPT that moving the lever to the neutral position should do NOTHING. Granted, if you lift the lever a little more, you will slightly open the brew valve and MAYBE start the pump but surely you can imagine the tolerances and adjustments involved in this.

Well, as Brenda Lee sang:

I'm sorry, so sorry
That I was such a fool
I didn't know
Scale could be so cruel.

I took the top bolt off the mushroom to inspect the chamber again. Some scale in the Gicleur afterall, wouldn't pass a pin (Did not look closely enough the first time). On the advice of a service tech, I put a tsp of citric acid in the chamber with a backflush disk in the portafilter. Added water to the top of the chamber and man o man did it bubble. Watched in fascination for a minute or two and replaced the mushroom. Let it sit for about 30 minutes and repeated after flushing. Let that sit for about another 30 minutes. Opened a checked and no scale in the chamber at all. Brew head got up to 200 F. I am now descaling the machine with Citric Acid 5% through the water line. Hopefully will have espresso in the morning...

I ordered the replacement valves anyway and figure that it is a small price to pay for a 4 year old machine. Hopefully I can get the brew head idling temps back to about 210 F with all of this.