6400- 88 Expanded Temperature Control Kit
Installation Instructions
LI-6400 Portable
Photosynthesis System
General Information
The nominal temperature control range of the LI-6400 sensor head block is ±6 °C from the ambient air temperature when the sensor head is exposed to full sun. The range of temperature control can be further increased
if the heat dissipation from the thermoelectric (peltier) coolers is assisted by water jackets inserted between the
coolers and the finned heatsinks.
The 6400-88 Expanded Temperature Control Kit contains two water jackets through which water is circulated
to aid in heat dispersion from the peltier coolers. With the kit installed, and no water flowing through the water
jackets, the LI-6400 has the same temperature response as the normal chamber block (±6 °C from ambient).
With water circulating through the water jackets, the chamber block temperature of the LI-6400 sensor head
can be reduced to less than 9 °C. With a temperature controlled water bath, the block temperature can be
reduced even further. IMPORTANT: Take care not to lower the block temperature below the dewpoint, as
water can condense and damage the gas analyzers in the LI-6400 sensor head.
The Expanded Temperature Control Kit leaves the peltier coolers as the primary control mechanism for the
LI-6400 sensor head. There are no programming changes required to use the kit. The water jackets’ sole
function is to remove heat dissipated by the peltier coolers more efficiently than the fans alone, providing a
wider temperature control range without changing the normal operation of the LI-6400. Once installed, the
water jackets can be left on the sensor head permanently; there is no need to remove the water jackets once they
are installed.
The kit contains two nickel plated water jackets with attached hose barbs, as well as screws and thermal pads.
One water jacket is fitted to each of the peltier cooling blocks on opposite sides of the LI-6400 sensor head.
Figure 1. The water jacket kit consists of two
water jackets; the water jackets can be connected
in series, as shown at left.
Water Jackets
Assembly Instructions
Tools required:
Phillips head screwdriver
5/64” hex key (included)
Time required: about 30-45 minutes
Assembly Instructions (cont.)
Notch
1.
Remove the 4 screws from the fan
shroud on either cooling block
assembly (Figure 2). Note that there
are washers on the underside of the
screws, behind the fan.
2.
Remove the 2 hex screws from the
finned heatsink with the 5/64” hex key
included (Figure 4). The 2 screws
removed here are not re-used, and can
be discarded.
3.
Thermal pad
Figure 2. Remove the 4 screws from
the fan shroud.
Figure 6. Place a thermal pad between
the through holes, nearest the notched
edge of the water jacket.
Figure 3. Remove the fan shroud and
fan.
Figure 7. Use the included 1/2" hex
screws to attch the water jacket and
heatsink.
Figure 4. Remove the 2 hex screws
from the finned heatsink.
Figure 8. Re-attach the fan and fan
shroud.
Note that one side of the water jacket
is notched to allow passage of the
wiring connections. Place a thermal
pad on the notched side of the water
jacket as shown in Figure 6. The
thermal pads do not have any adhesive; they will, however, “stick” to the
water jacket when pressed firmly into
place, or by moistening slightly.
IMPORTANT: Before starting Step 4,
please note that the white ceramic
peltier cooling block is fragile –
overtightening or tightening the
screws unevenly can crack the
ceramic. Tighten the screws evenly
(1/8 of a turn at a time), until just
snug. Do not overtighten!
4.
Remove
Place the finned heat sink on top of the
water jacket (the side opposite the
notch), and use 2 of the included 1/2”
hex screws to attach over the peltier
cooler (Figure 7). Note that the finned
heat sink is notched also, to allow
passage of the wiring connections.
5.
Re-install the fan, fan shroud, and
washers onto the heatsink in the same
order as removed in Step 1.
6.
Repeat the above installation on the
opposite side of the LI-6400 sensor
head.
Using the Water Jacket Kit
Peltier
Figure 5. Remove the heatsink. Note
that the white ceramic peltier cooler is
very fragile.
Figure 9. Use a 6" length of tubing to
connect the water jackets in series.
Use 1/8” I.D. Bev-a-line tubing or similar (not supplied) to connect the two water jackets to a water source. The simplest method of
use is to connect the two water jackets in series; use a short (about 6”) length of tubing to connect the two water jackets, as shown in
Figure 9. Connect one of the remaining connectors to the water supply (tap, or water bath), and the other connector to a drain, or to
the return side of the water bath. The water jackets do not require a very high flow rate of water to be effective. Note, too, that there
is no directionality to the hose barbs; either barb can be connected to the supply.
® LI-COR, Inc. • 4421 Superior Street • P.O. Box 4425 • Lincoln, NE 68504. U.S.A.
Toll Free: 1-800-447-3576 (U.S. & Canada) • Phone: 402-467-3576 • FAX: 402-467-2819
[email protected] • [email protected] • www.licor.com
PPS242_12/06