It appears that I should change the seat of the expansion valve on my Andreja. Would someone be kind enough to provide me with some guidelines about how I should proceed? I will be honest: I am not even sure I know where the expansion valve is.

Thanks!

Steve -

You want to change the expansion valve seat because the valve is screeeeeching !!!!!

OK - see the Chris' Coffee FAQ re removing Andreja's casing - http://www.chriscoffee.com/faq
Unplug machine and let her cool down, then remove casing.
You should have on hand a replacement o-ring for the pressure adjusting nut and a small quantity of Dow-Corning 111 Lube - available here (and maybe elsewhere) - http://espressocare.com/Qstore/Qs...ME=Dow+Corning+111

Detach the silicone hose which is a force fit on the adjusting screw outlet.

Unscrew adjusting nut - typically the pressure adjusting nut is screwed ABOUT half-way in so have a paper cup to catch the water that escapes when the plug "escapes" from the housing. Out will come the nut, spring, & valve.

Insert your little finger into the valve housing to feel for any scale buildup. If any is present, the valve body should be removed and soaked in white vinegar for about 30-45 minutes and rinsed/cleaned with a toothbrush.

Remove the old o-ring and lubricate both the groove for the o-ring and the new o-ring itself with about a matchhead's worth of lubricant. Use another matchhead's worth on the first inch or so of the valve body where the o-ring will rest.

Assemble the now "good as new" expansion valve, screwing in the adjusting nut ABOUT halfway. Apply some thread sealant to the male threads if you removed the expansion valve body. Be a little cautious when screwing the valve body back in - just snug is good.

Run Andreja (cold is fine) with a blind filter basket and adjust the valve till the brew gage reads 9.0 bar.

Hi,

Thanks for the thorough explanation. When you talk of o-ring, you have this in mind, right?


The reason why I want to change the seat is that I was told by the people at Chris that it might reduce the quantity of water that ends up in the drip tray when I pull a shot. There is no screeching at the moment.

Thanks again for the info.

Steve

The part you showed a pic of is the "rubber" insert (probably viton) for the expansion valve. It is NOT the o-ring.

Water from the expansion valve goes to the drip tray only for Vetrano and plumbed-in Andreja's. Is your's plumbed in or do you take water from a reservoir?

Wrong part...damn!

My andreja is plumbed in.

Like it's discussed in another thread (ristretto-shots-dramatically-cool-off-hx-t4492.html), I wonder whether I could gain more temperature stability if I could cut down on the hot water going in the drip tray.

Using your adapter, I have noticed that the water temperature decreases rapidly intra-shot (from 98 c to 94c) for a 25 seconds shot.

I will try to get hold of that o-ring then. Where does the rubber insert go, by the way?

Thanks for answering my newbie questions!

There exists a multitude of variables here - not the least of which is the POSSIBLY chilly temperature of your incoming water supply. The QM machines can typically take a production cycle of a touch over two minutes for temperature stability and REPEATIBILITY purposes.

If the adaptor shows a drop from 98 to 94 C, that is right in line with what I read with dear Anita. Keep in mind that brew water still has a couple of inches to travel and good things happen in those inches.

I would not change anything on your Andreja but I would order an o-ring and some lubricant to have on hand. If you order these parts, I would also add in some seals (a pair) for the brew lever and a spare grouphead gasket. The shipping for the o-ring probably exceeds the cost of the part. The rubber insert goes inside a brass valve housing which comes out when the adjusting nut is removed. You would remove, if you insist , the old rubber insert (from the back side) with a, say, 1/8" pin punch or ball point pen.