DIRC Water Chiller

Purpose: Cooling of DIRC front-end electronics

Location: Accessible part of the wall. South-side of IR2.

Operation: There are two water circuits: first, the cooling supply (two pipes at the lower back of the chiller) and main cooling circuit (two pipes on the right side (view from the front) of the chiller) and second, the main cooling pipes lead to heat exchangers mounted on the magnetic shield (backward door of the detector) near the DIRC front-end electronics crates.

Warnings and Interlock: Chiller warnings will cause the power supply of all 12 DIRC front-end crates to turn off after a one minute delay. The interlock is set by a SIAM card, located at Rack 07 in the electronics house. In case of an alarm: please double check that the electronics are really shut off: press the Drc button on the main detector control panel. Click on FEE Status which opens the DIRC CONTROL panel. Both, the DCC-DFB and the FEE CRATE lines should show red dots. If you find that the chiller problem maybe real but the dots are green (crates ON), please click successively all the 12 FEE PS buttons and shut the crates OFF.

Recovery: Once the problem causing the interlock is corrected, the system maybe restarted:

  1. Turn the chiller on and make sure it works properly
  2. Go into the electronics house and reset the flashing SIAM alarms (port 0 or/and port 1)
  3. Switch on the crates using the DIRC CONTROL panel of the detector control

Contact: In case of problems, call

Rene Candelario: x3189, pager: (650) 377-7464 responsible for our chiller
Marvin Jones: x3189, pager: (650) 570-8811 head of HVAC
Kingston Chan: x3894, pager: (650) 849-9422 contact in case none of above can help


To be checked:

  • Temperature of cooling water:

LED display, press LAST button until TEMP appears

    Nominal Temperature: 15 ± 1 ° C

  • Flow of cooling water circuit:

LED display, press LAST button until FLOW appears

    Nominal Flow: 4.8 ± 0.7 gallons/minute

  • Operating system pressure:

A pressure gauge is located at the right side of the water chiller

    Nominal Pressure: 50 ± 15 psi

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