(Jordan V., Gerardo M.)
We have noticed that the dew point at the dryer towers has been increasing since opening to HAM7 and or related to power glitch last Saturday, we are still looking into it.
We have had a constant dew point at the dryer towers of -72 oC, and now we are at -57 oC, because of those numbers we ran a short test, once work was finished for the day in-chamber, we stopped the purge air to the LVEA to see what the effect was on the drying tower's dew point, it changed but very slow, we started at -57 oC and after 20 minutes we ended up at -59 oC, and we noted that the right tower may be in trouble since the dew point did not improved while this tower "works", the dew point instead went up by the one degree, erasing the improvement of the left tower. We will look more into it.
To complete the test we took a dew point measurement at the point of use in the LVEA, and we got a -40.7oC, getting close to a bad dew point, and remember this is while no in-chamber work is going on, so please mind those C3 soft covers on chamber doors, thank you.
Today I power cycled the dryer towers for the purge air system, I did this to shut it off in a controlled manner instead of a power glitch/outage, like the ones from last Saturday, see entry here, and then restarted the unit back up, the dew point at the dryer towers improved by 4 degrees.
Also, I took a couple of dew point measurements at different places:
- Point of use, near the purge port near HAM4 yielded a dew point of -42.0 oC
- Near the dryer towers in the mechanical room, the dew point was taken before the big pressure regulator at the TMDS supply port, first with the left tower measured -42.1 oC, and a second reading with the right tower drying measured -42.7 oC.
In conclusion, despite the great demand of purge air, the dew point still is good, but please don't waste it, if you can please keep those C3 door covers closed. Thank you!
