SOB circulating pump problem
(experts Matt McCulloch and Jerry Va'vra)

Note: a recipe to restart the SOB degasing pump is available here.

The SOB water level is low because the circulating pump is off.
There should be a red alarm in the ALH channel 'SOB circulating pump' and, after a few tens of minutes, a yellow alarm on the SOB water level (without circulating pump the water level goes down slowly).


This problem is not critical as the SOB water will go down very slowly: unless the alarm level is high (red flag in the ALH), there is no need to page immediately the DIRC water experts and the problem should not interfere with data taking. Therefore, our response should depend on when the problem occurs.


Go to the DIRC water plant. First, check the following points :

  1. The power button is in ON position, the "power" light (green) and "run" light (orange) are on
  2. The "low water" light is off
  3. The PUMP 2 is selected (WARNING: this setting can change with time, check the green sticker location)
  4. The two outlet flowmeters (not shown on the picture) are about 1.5 each and the water level in the tank must be between the 2 green marks
  5. Go directly to the circulating pump : it is noisy or you can feel vibration when you touch it.

:Picture of the panel of the circulating pump:

Here is the procedure to restart the circulating pump (from Bob Reif). When the circulating pump is not running, the panel is likely to show the following configuration:

To restart it, try the following steps:
  1. Put the power buttton on ON position (the power light must be ON)
  2. Check which PUMP (1 or 2) is selected. Switch this button into the OFF position
  3. Put the RESET/OPERATE button into RESET position. It will automaticaly go back to the OPERATE position
  4. Select again the PUMP which was previously set.
  5. The circulating pump should be running now. If not, further investigations should be let to DIRC water experts and/or SLAC technicians.
Web Page by Guillaume Therin
Last modified: Wed May 3 19:49:24 PDT 2006 Nicolas Arnaud