Expansion valve leaking water

[Throz]

So, how much water does YOUR machine put out over a day?

I have a new S1V2, and it has been leaking anywhere from 10 to 20oz of water in 24 hours (well, technically half that in 12 hours). I've talked to Chris Coffee, and they seem to be seeing the same thing.

The confusing thing to me is that my friend also has a S1, the V1, but has had the board upgraded to a V2, and his puts out basically zero water. It drips during the heating cycle, but evaporates quick enough that he has no accumulation.

It seems mine drips ~10 drops every heat cycle, which is about every 2.5 minutes (From start to start). The basic math works to be about right (0.05ml per drop of water, ~24 heat cycles per hour = (0.05 * 10) * 24 = 12ml -> ~0.4 oz.

I've cleaned my expansion valve, and even installed a new one.

So what kind of water are you guys losing?

Thanks!

[chas]

That could be about right. The bottom line is that the tighter you make the expansion valve the less it will drip. However, it's supposed to be set to just barely start opening around 12.5 bar to ensure you don't overpressure the group boiler. My recommendation is to check that it is adjusted to 12.5 bar. If it still drips, get over it.

[Throz]

Yes, I've checked that the valve is set at 12.5 bar (numerous times).

If it leaks a lot, that's fine, i guess? Even talking with Chris Coffee, I guess the range that their machines leaks is wide as well.

Too bad the drain kit isn't powered with a pump. I'd install that, but don't want to drill holes in my counter top.

[Louis]

The confusing thing to me is that my friend also has a S1, the V1, but has had the board upgraded to a V2, and his puts out basically zero water. It drips during the heating cycle, but evaporates quick enough that he has no accumulation.

Just some theory:

Water drips when the coffee boiler gets hotter, as water expands. This happens in a significant way when the machine is turned on but also during normal boiler cycling.

If the new board comes with a more precise digital thermometer, could it be possible that it drips less during the heating cycles? i.e. a 2°C deadband of a ±1°C thermometer could let more water out? (pulling fresh water in as it cools, pushing hot water out as is heats)

In my case (newest board), it lets only a few drips out on each heat cycle. I flush my group water in a small plastic bowl I keep at hand so the only water ending in the drip tray comes from the expansion valve and from steam nozzle purges. The machine is on 2x 3-4 hours per day. I empty my drip tray once a week.