The input temp to the heat exchanger from the 15 K line dropped down to 18 K; Adesh suggests, and I agree, that we should up the fan speed. We set it to 20 Hz (by entering 67 in the GUI input window; there is a factor of 3 needed).
This brings the input temp at heat exchanger back up to 19.2 K.
Then, I get a call from Matt Wright of Cryo; they saw the increase on the temperature of the cold return to ESR, and wanted to check what caused it. I explain the fan speed change, and he explains that the opening up of the 15K supply valve was "automagically" opened up by a controls based on the temperature (which one, I'm not sure).
Matt assures me he has a plan for the 4 K issue, and tells us that he will be the cryocontact today (his extension is 7722, and his pager is 327-5506), not Robert Norton, who is home recovering from his cold.
We decide to wait until Silviu arrives (he is expected in in 20-30 minutes) to re-start the 4 K flow (discretion is the better part of valour).