I'm going to answer my own question here. I did a search on this and found an article on coffeegeek.com that seems to describe my problem pretty accurately.
http://coffeegeek.com/forums/espresso/machines/528423 It does seem like my vacuum breaker valve is misbehaving. The good news is that this is a relatively inexpensive part, $12-$20. One of the comments in this thread is: "Another sign that it is the vacuum valve (the valve that seals the boiler once the machine reaches temp), is that the BII will occasionally burp the pump very briefly throughout the day to replenish water from the very slow steam leak." This is exactly what is happening to my Brewtus so it looks like I'm in the market for a vacuum breaker valve. On Tuesday, May 28, 2013 9:23:53 AM UTC-5, winnipegger65 wrote: > > I have my brew temperature set to 96 Celsius. I am finding that when I > pull even one shot (less than 30 seconds), the temperature can already fall > to 95C. It never used to do this. I first wondered if this was related to > the PID settings but now I have my doubts. > > I don't know if this is related but I also noticed that the pressure > release on the steam boiler hisses a bit so obviously some pressure is > escaping. This does eventually stop but wondering if these two things are > related. > > -- You received this message because you are subscribed to the Google Groups "Brewtus" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/brewtus?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
