Instructions to recover from a Chiller problem
Check the following four points explained in detail below:
- Check that the DIRC chiller itself is running fine without any failure
- In case the DIRC chiller is currently replaced by the BCS, check
that the BCS is working fine.
- Check that the SIAM has the correct settings.
- Check that the Front End Electronics is switched on.
- Check that the 'DIRC chiller drain valve' is closed.
Check the DIRC chiller
Go to the DIRC chiller at the south wall in the main hall.
(Please note that it might look different as Brandon might not always
Go to the main panel and check:
- Is the chiller switched on? If not press the main switch first,
then the on/off button.
- Is the chiller on but showing a blinking error message on the
LCD display (e.g. compresor pressure failure)? If so, switch the
chiller off with the main button. Then, go to the back of the
chiller and press the reset button for about 2 seconds.
Then switch the chiller on again.
- If the chiller does not start, it may be because the
temperature on the display is higher than
24 degrees Celsius. See the 'Resetting the Temperature Limit'
section below for the procedure to be followed.
- Level fault. Open the Refill opening. Unscrew the small top lid.
Check that the water level is close to the top of the lid. If not,
refill with normal, clean water.
- Flow fault. This error might appear if the pipes are empty as the
return flow from the detector is measured. If it persists, make
sure there is no leak in the pipe of the magnetic shielding.
- Low/high temperature. The chiller will cool or warm up the water
automatically. You should see the temperature on the chiller
display get closer to the temperature set.
As of October 2007 a thermocouple has been inserted in to the
water reservoir. The temperature variable is read through
epics in the following panel:
BaBarMain-->CEN--> (variable name : ??? some channel number
showing up on the pannel)
It can also be found in Ambient : drc-->Chiller-->waterTemperature.
Other problems might be that the chilled water supply into the chiller
is down. To check this, look at the pressure and temperature reading on
the big chiller water pipe on the wall. If there is a problem, inform
the run coordinator and the other subsystems (DCH, EMC) as they use the
same supply and will get into trouble too.
Check the BCS
This is handled in the BCS documentation of the Care and Feeding Manual.
Check the SIAM
Go to the electronics hut, rack 7 and search the DRC-MON IOC.
Two SIAMs (#0 and #1) are responsible for the DIRC chiller, they are shown on
the picture below.
On SIAM#0: channel 0 monitors the Chiller On/Off, before January 9,
2008 this channel was connected to a relay on the chiller power
line. There used to be lots of glitches in this line, so a new flow
sensor was in stalled outside the chiller. This sensor consists of
two pressure sensors; one the outgoing water pipe and one on the
return water pipe. The pressure difference closes a set of dry
contacts which gives the chiller OK signal. Channel 1 is also a flow
sensor but it only fires if there is a flow fault while chiller is ON.
In the normal configuration, the SIAMs should look as shown in the
picture (it is normal for the HV siam (#2) to be tripped during data
taking. For further details see
here). For chiller-related problems, forget about the HV siam (#2
on this picture) and focus on the SIAMs #0 and #1. For all channels only the green OK light should be on,
but for the BCS channel. There the yellow INH(ibit) light should
be on and in addition the green OK and/or the red TR(i)P light.
In BCS mode, in the BCS channel only the green OK light should be on,
the two upper channels should have the yellow INH(ibit) light should
In case the situation is different, do the following:
- INH(ibit) status is different
- Search for two thin objets, such as a pen. Press the inhibit
button at the lower part of the SIAM and at the same time press
the r(e)s(e)t button of the channel you want to toggle the inhibit.
- Red and green light is on
- Reset the trip by either using the EPICS SIAM panel or by pressing
the r(e)s(e)t button of the channel you want to reset with the
- Only red light is on
- The channel is still in alarm mode. Fix the problem at the chiller
Check the Front End Electronics
At this point, there should be no more Beta alarm and no more chiller
alarm in the alarm panel.
To switch on the Front End Electronics, go to EPICS, open the DIRC panel,
open the Wiener panel and press the Global On button.
If no crate switches on, there might be a problem with the relay. Call
the DIRC expert (and maybe Ray Rodriguez or Sam Zalog).
Resetting the Temperature Limit
Go to the chiller and look at the buttons on the main panel.
Do the following steps:
- Get into the setup loop by pressing and holding the ENTER button and while
holding it pressing the NEXT button. The display will show SETUP?.
- Press the YES button. The display will show LOW TEMP?.
- Press the NO button. The display will show HIGH TEMP?.
- Press the YES button. The display will show HIGH 17.0C.
- Press the YES button to change the temperature setting. Set it to a value
at least 7C lower than the current water temperature. Leave some room
for warmer water coming in from the pipes.
- Press the ENTER button and then the NEXT button. The display will show
- Press the NO button until the display shows SAVE?.
- Press the YES button. This will bring you back into the operators loop.
- Switch the chiller off at the main switch.
- Press the reset button at the back of the chiller. Hold it for about 2 to 3
- Switch the chillers main switch on.
- Press the ON/OFF button. The chiller should start running and cooling
- Observe the current temperature in the main panel. At the beginning it
might rise a little as warmer water might come in from the pipe. After
some time the water should get colder.
- When the temperature is consistently below 22C, use steps 1 to 8 in
order to set the temperature limit back to 17C. Use the NO button instead
of the YES button to lower the value in step 5. There is no need to
switch the chiller off during or after the changes.
DIRC chiller drain valve
This problem already occured at least twice in the last year so it's worth checking this valve before paging HVAC people and/or switching to the BCS. The point is that this valve is so tiny that moving it is very easy -- and one is likely not to notice this action whose effect is immediate!
View of the main valve panel: the DIRC chiller drain valve is at the bottom right. In case you're lost in the IR2 hall, the valve panel is between the DIRC chiller and the E.H.
When using the DIRC chiller, this valve has to be completely closed (i.e. in horizontal position, check the back side of the valve to be sure): opening it by few degrees is enough to slowly drain the chiller water!
- The chiller maintenance is made by the HVAC people. In case of emergency they can be paged -- see the C&F manual for details. If the request is not urgent, they should be contacted using the CEF request web form. To reach it, go to the SLAC main page, open the 'For Staff' menu and click on 'CEF Requests'. Then log on the form using your windows password and 'slac\your login' as login.
Troubleshooting: unfortunately, this works only on Windows machine!
- A recent version of the chiller manual is available here.
Web Page created by Thomas Hadig
Last modified: Sun Feb 12 10:21:52 PST 2006