Troubleshooting
6400-01 CO2 Mixer Problems
20-28
Using the LI-6400
20
The Bad Valve Saga
If your LI-6400 has serial number 437 or above, then this discussion does not
apply to you.
In 1997, we discovered that a number of mixers were failing in the field. The
typical failure mode was inability to control CO
2
at the specified targets after
prolonged usage. (Example: ask for 300, get 1000). The problem was traced
to an internal valve whose seat was failing when exposed to pure CO
2
. The
valveÕs manufacturer had changed the design from one that worked to one
that didnÕt. LI-COR issued two Service Bulletins (#2 and #3) about the prob-
lem
4
, and notified affected users. A field replacement kit was offered (part
number 6400-909), and by the end of 1997, about half of the potentially af-
fected units had been replaced.
Determining if You Have a Faulty Valve
You do not have a faulty valve, if at least one of the following statements is
true:
¥
Your instrument does not have the 6400-01 CO
2
mixer option.
¥
Your instrumentÕs serial number is 437 or above
A good valve will have already been installed.
¥
A Ò6400-909 InstalledÓ sticker is on the bottom
Normally, this little sticker would be on the bottom plate next to a leg. In the
case of field installations, itÕs up to the user to place this sticker, so thereÕs no
guarantee that it will be there.
¥
White tape on the solenoid
The original design (which does not have the problem) had white tape on the
winding of the valve in question (see Figure 20-5), instead of yellow.
¥
The mixer serial number is CCA-
nnn
rather than CC-
nnn
.
See Figure 20-5 for the location.
¥
A red dot is painted on the brass end of the bottom valve (Figure 20-5).
Valves in the 6400-909 kits have a red dot on them.
4.
The information in Service Bulletin #3 is contained in this discussion.
Summary of Contents for LI-6400
Page 1: ...Using the LI 6400 Portable Photosynthesis System ...
Page 15: ...Part I The Basics ...
Page 16: ......
Page 174: ...Making Measurements Answers to Questions 4 56 Using the LI 6400 4 ...
Page 175: ...Part II Useful Details ...
Page 176: ......
Page 200: ...Standard Tools Power ON Hooks 5 24 Using the LI 6400 5 ...
Page 214: ...Real Time Data Real Time Graphics 6 14 Using the LI 6400 6 ...
Page 234: ...Environmental Control Light Control 7 20 Using the LI 6400 7 ...
Page 244: ...Light Sensor Considerations Gallium Arsenide Phosphide GaAsP Sensor 8 10 Using the LI 6400 8 ...
Page 288: ...Data Logging Making Your Own AutoPrograms 9 44 Using the LI 6400 9 ...
Page 289: ...Part III Working With Files ...
Page 290: ......
Page 312: ...The LPL File System Troubleshooting 10 22 Using the LI 6400 10 ...
Page 340: ...Downloading Files Using a Data Capture Program 11 28 Using the LI 6400 11 ...
Page 375: ...Part IV Configuration Issues ...
Page 376: ......
Page 420: ...Defining User Variables Old Style vs New Style 15 18 Using the LI 6400 15 ...
Page 454: ...Using an Energy Balance Further Reading 17 12 Using the LI 6400 17 ...
Page 455: ...Part V Maintenance Troubleshooting ...
Page 456: ......
Page 572: ...Troubleshooting Useful Information 20 46 Using the LI 6400 20 ...
Page 593: ...Part VI Programming ...
Page 594: ......
Page 622: ...Programming with LPL Compiler Directives 22 28 Using the LI 6400 22 ...
Page 846: ...Index I 16 Using the LI 6400 ...