Hi, should the pump gauge on the pro 700 read 0 when the pump is not running?

I thought my did when I first got the machine but then after a week I noticed it was reading 3-3.5 bar and brew pressure had gone up (past the green zone).

I suspected too high input water pressure and adjusted my pressure regulator to minimum (I have no meter at present to independently check) which brought it down nearer to 0.

My question is, does this gauge show input water pressure?

Should it read 0?

What do other people's meter read?

The other change I noticed is that the pump now sound more cracklely when running. Could this be due to under or over pressure?

Many thanks
Jeremy

When plumbed it will not read zero. It will be based on what your upstream water regulator setpoint is. That's basically your pre-infusion pressure now.

I think you should turn the pressure back up again.

The "crackling" noise may be a result of insufficient water flow and/or cavitation caused by having the output pressure very restricted. Those things can cause pump damage very quickly.

Pressure regulators normally specify what is the maximum allowable delta between input and output pressures to avoid this. Some also specify a minimum length of downstream pipework before any subsequent water draw-off or appliance.

Your machine's instructions should specify what the minimum and maximum allowable input pressures should be. As bikeminded said this creates the pre-infusion pressure in machines with the e61 group.

My question is, does this gauge show input water pressure?

Yes . . . with the machine turned OFF, lift the brew lever and the gauge will show your input water pressure to the pump. Profitec specifies ABOUT 1.5 bar or whatever is in their manual.

Profitec says input pressure should be 0.5-2.0 bar.

Thanks for all your replies.

I have turned up the pressure so that the pump gauge matches the recommended input pressure, approx 1.5 bar with the brew lever closed. This drops a little when I lift the brew lever into pre-infuse position however I would expect this as the water now flowing.

This has also improved the sound of the pump.

Under load the pump now reads 10 bar on a backflush and about 9.5 bar on coffee brew.

Is this a little high, should consider reducing the pump pressure by adjusting the screw on the pump?

Many thanks
Jeremy

Hicks wrote:
Under load the pump now reads 10 bar on a backflush and about 9.5 bar on coffee brew.

Is this a little high, should consider reducing the pump pressure by adjusting the screw on the pump?

Sure, play with it. It's simple to change (at least until I plumbed and drained my machine and can't pull it out anymore). Mine arrived around 8 bar and I dialed it up a bit.