Hi Guys, I need some help, it might be a pretty basic question. I own a silvia V3 with a Fuji pid. I have it set the temperature 216F. When I pull a shot the temperature drops significantly to 183 till it starts going up again. Is this normal? I did the automatic tuning for the pid.
Thanks for your help!

Yes, it is normal for the display to drop during the shot although I have no idea how much is normal for your machine. The display is showing the temp measured at the probe which is influenced by the cold water entering the boiler as you remove hot water at the grouphead.

that sounds about normal. My silvia is set at 106c and drops to 85c by the end of the shot. Nothing to be worried about. As mitch said, that's just the probe picking up the cold water entering the boiler from the reservoir. That's not the actual temp of the water at the group.

As mitch said, that's just the probe picking up the cold water entering the boiler from the reservoir. That's not the actual temp of the water at the group.

Boy, this begs some significant questions. Among them:

What do the readings the OP gets imply about the "actual temp of the water at the group?"

What does the intrashot temperature curve at the group look like?

How long (or how much flow) does it take before a reading of a large temperature drop resulting from "picking up the cold water entering the boiler" registers at the group?

BDL

It bothers me that I can't fully explain why, but the intrashot profile slightly rises on a Silvia (Scace and grouphead measurements), even while the temp at the top of the boiler is dropping. Once water starts moving through the system the link between boiler temp and shot temp is broken.

Ristretto shot profiles rise more than lungo shots. But AFAICT they all rise a little.

Jim

bandoleir wrote:I own a silvia V3 with a Fuji pid. I have it set the temperature 216F. When I pull a shot the temperature drops significantly to 183 till it starts going up again. Is this normal?

My set point is a bit higher (218 I think at the moment) but 183 sounds a bit low off the top of my head -- though I can't recall what mine dips to. Are you sure you're starting with a full boiler?

takeshi wrote:My set point is a bit higher (218 I think at the moment) but 183 sounds a bit low off the top of my head -- though I can't recall what mine dips to. Are you sure you're starting with a full boiler?

FWIW, the magnitude of the temperature drop seems to be most closely related to flow rate.

Jim

Pids do not fully stabilize the temperature during brew. This is due to the limitations of the small heater. In order to compensate for the drop you can do a preheat coil mod to the Silvia boiler by wrapping the boiler in coils of 1/4 inch copper pipe. I did this to y gaggia and i have it set to 99.9 and the lowest temp it will drop is to 98.3. This mod definitely improves efficiency. It's harder to drop the temperature of a large piece of mass.

boar_d_laze wrote:Boy, this begs some significant questions. Among them:

What do the readings the OP gets imply about the "actual temp of the water at the group?"

What does the intrashot temperature curve at the group look like?

How long (or how much flow) does it take before a reading of a large temperature drop resulting from "picking up the cold water entering the boiler" registers at the group?

BDL

I can tell you based on my own measurements that the PID readout is only useful for setting brew temps and knowing when the machine is ready after changing the desired brew temp. Otherwise, I ignore the readout, certainly while I'm brewing.

If this really concerns you one of the answers would be to get something along the lines of an Elektra T1, which has a 5.5 liter boiler and a high wattage heating element. As a side benefit it'll keep the area where you have it nice and toasty on those cold winter days but come summer, it's an altogether different story.



Now that's what I call a real boiler