Anyone adjust the pstat on their machine in the wintertime when the water temp drops?

Why would you? Given that the gas law (PV=nRT) is still relevant even at lower temps - having the same pressure will result in the same temp.

All winter would mean is that the pressure switch will switch more often as the boiler cools quicker...

AssafL wrote:Why would you? Given that the gas law (PV=nRT) is still relevant even at lower temps - having the same pressure will result in the same temp.

On my Londinium (where water heats the group via a thermosyphon) I make a small adjustment to the pstat as the ambient temp changes (in summer and winter). As the ambient temp affects the heat of the group, and thus the overall shot temps. Generally about .05bar swing between summer/winter.

Right now my L1 is sitting around the 0.9 - 1.15 bar range.
I have my friends Rocket E61 HX sitting at about the same.

Always assumed that wouldn't be necessary on an HX machine. Learned something new.

Its more: detached group vs saturated group
For a detached group, it doesn't matter if it's connected to a HX/DB, or Pstat/PID.

Detached groups temperatures (where heated by thermosyphon or direct-connect/dipper) are tuned based off an assumed ambient temp. If your ambient temp wanders to much (such as summer winter) you may wish to account for it.

For instance, my house in winter is around 20-22˙C, and summer is 24-27˙C; thus I slightly adjust my temp.

Thanks for the replies guys. My La Spaziale New EK (commercial machine), has its own unique HX setup. As far as I know, the cold water doesn't pre-heat like on other HX machines by running through boiler water for some time...it is heated in a chamber which is only heated by boiler steam. As I sit here and look at a diagram and read your posts, I am not sure I understand why anyone would adjust the pstat on this machine. It seems that the only way to affect brew water temp is by altering flush times.

But, then again, I am just a caffeine addict, not a physicist.

nickw wrote:Its more: detached group vs saturated group
For a detached group, it doesn't matter if it's connected to a HX/DB, or Pstat/PID.

Detached groups temperatures (where heated by thermosyphon or direct-connect/dipper) are tuned based off an assumed ambient temp. If your ambient temp wanders to much (such as summer winter) you may wish to account for it.

For instance, my house in winter is around 20-22˙C, and summer is 24-27˙C; thus I slightly adjust my temp.

My assumption was based on the theory that thermosyphons increase the flow rate the higher the temp difference between the boiler and the syphon mass - the group. Hence the colder the group - the more the syphon will flow. Which is probably true, but also means the end temperature will be slightly lower or the needed flow to maintain temp will cease and the group temp will drop. (I guess the saturated group keeps our brains lazy..)

So it would be wise for detached group owners to invest in a Scace device to maintain the offset temperature as ambient conditions change? or is the difference minute in household conditions?

nickw wrote:For instance, my house in winter is around 20-22˙C, and summer is 24-27˙C; thus I slightly adjust my temp.

Same here, I bump my idle coffee boiler temperature up one half-degree to a full degree (Fahrenheit) to compensate for keeping the café much cooler than during the summer season.

AssafL wrote:So it would be wise for detached group owners to invest in a Scace device to maintain the offset temperature as ambient conditions change? or is the difference minute in household conditions?

Depends on how much the room temp varies with the seasons. I've Scace tested my Speedster in Winter & Summer & found no need to change the offset. The flush/no flush routine I use to select a brew water temp for the Bosco is based on Scace testing with a room temp in the 72°-75°F range. No central AC in our old house so on hot summer days it's either no flush, no Bosco or break out the Scace & tweak the P'stat for July/August.

I thought speedster is a saturated group - it would'nt change that much...