Hi, I'm hoping someone can tell me if what I'm experiencing is normal. I've been backflushing more frequently on my 2mo old Expobar Lever. I see a very strong backflow into the drip tray after the first backflush.

What is strange is that subsequent backflushes seem to have less powerful releases into the driptray. Even if I count for a few more seconds after pressure builds up. In fact, it seems the longer I wait to release, the less dramatic the release is. I'd expect the opposite. Sometimes I hear my OPV whining, but not so frequently as I used to. Any suggestions?

Thanks!

First back-flush is probably flash boiling and subsequent flushes are not at the boiling point.

My reasoning would be that during the first backflush, the blanking basket and the pathway up to the valve is filled with air. When you let the water in and begin building up pressure this air is compressed, when you open the valve this air expands and forces the water out as fast as possible. During the next flush the blanking basket is already filled with water, hence there is less air overall in the group, and the less air that gets compressed the less is there to expand and force the water out. Make sense?

That makes sense. But I used to see pretty even amounts each time, now it seems to diminish. Nickle's response makes sense somewhat to, since my first flush is the strongest, but I'm not sure how water temperature figures in.

One other thing I've noticed is on some shots, my thermometer sometimes shows the temperature constantly decreasing. Usually, it holds at 204-205, but these shots start at 205+ and sink down to 197 or so. Almost as if I were flushing the group instead of making a shot.