I have an Astoria CKE automatic, about 9 years old (which I received used a couple years ago), using a traditional heat exchange system. From a cold start, it performs normally. By engaging the pump with the button pad, water pours from the group head at what seems to be a normal rate. At this stage it is not yet heated up. By the time everything is up to temperature, however, engaging the pump spits out a small amount of water, then blows only steam, and eventually the volumetric doser will time out.

At first I thought I simply had to bleed out the group head by loosening the nut that covers the jet. But here too it lets out only steam, except when cold when it appears to saturate. The hot water spout (which pulls from its own heat exchange) also produces only steam.

The machine use to push out only water from the group head, but at a significantly slower rate than expected. After a de-scale, it seemed to be moving significantly more water, only with varying flow rates for a while, until settling on this abnormal behavior. I have used two separate vibe pumps, both of which tested fine.

Any ideas would be appreciated.

Phil Proteau

It seems to me that you have leakage in the hx circuit which is allowing the steam to form. When I look at the hydraulics of your machine, available here: http://www.archive.org/details/AstoriaCkManual, it could very well be the hx circuit's expansion valve (item 24 on page 31 of 50).

Do a little touching on the pump discharge piping with the machine unplugged (but fully warmed up) and you may easily locate the source of the leak. Or, even easier, that expansion valve probably relieves back to the drip tray and you should see evidence of a continuous leak.

Hope this helps.

Thanks for your time looking at this.

The model I have is shown on pg 33 and does not have the #24 expansion valve, but only the pump expansion valve. The #14 teflon tube brings the expansion water back to the intake instead of draining into the pan. My machine is not plumbed, and sits on the workbench at the moment, and has no leaking anywhere. The only thing going into the drain pan is the drip from the 3 way.

I bled the group head again as well as the pump expansion valve while the pump was engaged. I still get the steam. I noticed that the best water flow is not while everything is cold, but semi-warm, when the water in the heat exchange and the steam boiler is hot but not above boiling yet. Fully bled with some water expansion, the group sends copious amounts of water out. Once it has reached full temp, it is back to blowing steam.

I am beginning to think that the water is not able to get into the heat exchange properly. There is a filter and flow restrictor in-line at the intake before the pump, and I wonder if it is clogged. If the water is not filling fast enough, then the heat exchange water can gain a little head room and vaporize faster than it can fill up. I will try undoing and cleaning out all the intake compnents.

Thanks,
Phil

. . . the group sends copious amounts of water out.

What is the flowrate during the "just warm" condition - maybe 8 ounces in 30 seconds?
Did you touch all of the pump discharge piping, looking for a hot spot? If the check valve (item 4) is leaking, that would likely produce this same symptom.

What does your boiler pressure read after a hour or two at idle?

when the machine is hot:
continue to run the machine even it only comes out in steam, until you see water come out.
wait for few minutes, run it again, steam or water?
check the pump whether it's hot.

As for the boiler pressure, it hovers between 1 bar and 1.4 which is where I have it set. It has a wide swing, but it holds true to this.


If I let it run continuously, it will blow steam continuously, never going back to water. Both pumps I have used check out fine.

I think that the check valve/non-return valve is the most likely suspect. The fact that it bleeds right back to the intake hose, (for the pump expansion valve return) makes it impossible to see if it is flowing back against the check valve. If I remove the expansion tube that would be carrying this water in order to test the check valve, I would need a proper cap to seal off the input back into the intake hose (a cap which I don't have). Come to think of it, if I let it fill up while it is cold and then mark the water level in the reservoir, it will register if a significant amount of water flows back from the heat exchange after heating up. I'll perform this test and check back here after with a progress report.

The check valve and its connecting pipe (item 5) would be pretty hot.

It could be a clogged flow meter, very restricted water flow through this puppy.
Remove it and check for restrictions. Sometimes the fittings at either end of the hx get
limed up too.

It is also possible your HX pipe has a crack so steam is leaking into the pipe.

Something like this:
http://gi92.photobucket.com/groups/l39/ ... otto12.jpg


That would explain the constant flow of steam.