www.klatchroasting.com: USBC champion, voted 2009 'best micro-roaster'

How to adjust an old Penn pressurestat?

Postby itsallaroundyou on Thu Jul 23, 2009 12:33 am

Does anyone know how to adjust (in a predictable way) the old style Penn pressure stats? I've been fighting with one in a gaggia orione for about 3 hours, and the adjustments and their results is just not intuitive to me. i'm planning on replacing it with a Sirai p-stat, but since this one is here now, i'd like to get it working.

Image

there are 3 adjustment screws: one in the back left adjusts the overall tension of the switch, the front corner controls the cut in setting, and the last one adjusts the cut out setting.


the numbers on the p-stat gauge do not correspond to what the boiler pressure gauge reads. i don't think i'm understanding how the cut in and cut out are related. i thought that i'd set the cut out to the max pressure i'd want, then set the cut in to kick on at the lowest pressure i'd want. the problem if i get one set to where i want it, i can't get the other set as well. maybe i need to buy a Heisenberg compensator? any advice would be greatly appreciated...
"If it wasn't for venetian blinds it'd be curtains for us all"
User avatar
itsallaroundyou
 
Posts: 129
Joined: Dec 11, 2008
Location: santa barbara, california

Postby Paul on Thu Jul 23, 2009 2:51 am

hello mike,

sorry, I cannot offer advice regarding your penn. May I humbly suggest that it would be wise to replace it with a nice, shiny (and adjustable!) sirai pstat. I suggest replacement purely for safety reasons. I also fit modern safety valves to vintage machines.

best of luck!
cheers
Paul

LMWDP #084
Paul
 
Posts: 509
Joined: Jul 10, 2006
Location: Christchurch, New Zealand

Postby zubinpatrick on Thu Jul 23, 2009 4:34 am

Can't tell you much except that pressure stats like this can be a PITA to set. Also for starters the cut in spring is too compressed. I would back everything off a little, and find the balance. My experience is more with compressor pressure stats but the idea is the same, but like I said a PITA. Feels good when you're done though.
zubinpatrick
 
Posts: 209
Joined: Jan 16, 2008
Location: montreal

Postby itsallaroundyou on Thu Jul 23, 2009 10:32 am

paul---i've already got an over pressure valve waiting to replace the big lead "safety valve" :)

zubinpatrick wrote:pressure stats like this can be a PITA to set


glad i'm not the only one who's had a problem with them. i'm really starting to think that something is really wrong with it, and its not just operator error. but, for financial reasons, i have to wait till after my trip to NZ to do my parts ordering, i will probably tinker with it more and see what kind of progress i can make.
"If it wasn't for venetian blinds it'd be curtains for us all"
User avatar
itsallaroundyou
 
Posts: 129
Joined: Dec 11, 2008
Location: santa barbara, california