It is a Watts model 263 3-way small pressure regulator. ¼ to ½ inch. Here is a link to Watts product spec page
http://www.wattsreg.com/pdf/ES-26A-263A.pdf

The pressure has settled in on the gauge. I am running it at 25psi and it supplies ample flow to the machine.

I had the wife pick it up at the local plumbing supply store, I believe it was around $60.

Cannonfodder:

Thanks for the information and the link--Watts' web site design would have made that a long search for me!

Fred

I've been noticing that the pressure gauge on my Chris' Coffee pressure reducer has been reporting abour 80 psi. So, I bought a test gauge at Home Depot and confirmed that the input pressure to my house was 130 psi. My brew pressure was not affected thanks, I guess to the internals of my S1. My shot pressure measured at 8.5 bar. Still heedful of various cautions I have been reading about, I had a new reducer installed. My house pressure is now 65 psi. The pressure on my Chris' Coffee reducer is alas still 65-70 psi. The poor thing must be fried. The reduction has not affected my shots which continue at 8.5 bar. I'm not sure that I want to bother with reducing it further, since nothing is leaking. What do you think?

Bob

I thought I'd add the url of a site that sells pressure reducers that seem tailor made for this application. What do you think of these babies? http://www.plastomatic.com/pressure-regulators.html Especially this one which seems to go the extra step to ensure water purity. http://www.plastomatic.com/pru.html