jason.oberling@LIGO.ORG - posted 16:19, Thursday 09 November 2017 - last comment - 17:50, Thursday 09 November 2017(39364)
PSL Enclosure Make-up Air Found OFF
During today's 1pm PST meeting it was noticed that the PSL enclosure temperature had increased to over 80 °F, and had been increasing for ~18 hours. After the meeting (~1:30pm PST) I went out and checked the status of the environmental controls and found the HEPA fans, AC, and make-up air all OFF. The proper setting for science mode (which the PSL was supposed to be in for the ongoing IO alignments, see alog here) is HEPA fans and AC OFF, make-up air ON at 20% fan speed. I restored the PSL environmental controls to the proper setting and the enclosure temperature should start slowly coming back down. Something happened yesterday evening to turn off the make-up air entirely, at this point we are not sure what.
When I went into the enclosure on Tuesday, I also noticed that the "default" speed of the ante-room and laser room HEPA fans was set at 20% (it should always be 100%). I changed it from 20% to 100%, waited a few seconds (~10), scrolled back through the menu to find that the speed was set back to 20% again. I had to repeat this two or three times to get the default value to stick. I had left the make up air at 20%, the science mode speed. By comparison with the HEPA fan speed settings, the make up air setting seemed well behaved. I left the air conditioning off, without toggling the circuit breaker.