Tekmar 3000 Leak Check: no "Feed Pressure"

[LALman]

I have a Tekmar 3000 Purge and Trap unit. When I use the hand controller and go into manual mode and select "B Feed Pressure" I don't get any pressure. I figure either a valve is not closing or not opening. But which one?

My work around at present is to step the unit into dry purge and block the vent (putting unit in Bake out also works). This works to get the pressure. Then I use reset to abort the run and go back into manual mode and select "C Leak Test". Then I hear a click (vent valve closing?) and I can unblock the vent and see if the unit looses more than a couple pounds of pressure over 5 minutes.

Has anyone had this problem with the "Feed Pressure" function not working? I have some new solonoids and can swap them in if needed. But I don't know which one. The vent valve seems to work and the unit operates in tandem with my Archon 4552 and 5903/6890 GC-MS without apparent problems. My service guy says over the phone that it could also be a corrupted bios making just that menu selection unavailable.

Is there a secret service menu that can be used to trigger the solonoids one at a time for testing?

Any thoughts?

[LALman]

I got a copy of the manual on line and searched for "pressure" until I found the place (~pg 63). Apparently, you must go into setup, select "gas flows" and turn "standby flow" to "ON". This will then enable "feed pressure" to work. This will also allow you to set trap pressure and sample flow.