LI-8250 Multiplexer and 8250-01 Extension Manifold maintenance

The LI-8250 Multiplexer and 8250-01 Extension Manifold are designed to require little routine maintenance. Most of the components are modular and are intended to be easily replaced if needed.

Note: Before doing any maintenance or repairs to the components, first disconnect the instrument from the power source.

Replacing the air filters

The multiplexer and extension manifold include nine air filters. Eight of these filters are associated with the IN port on the chamber connection panel and there is one blue Balston filter between the valve manifold (inlet) and the system manifold or pump. These filters should be replaced if you are experiencing low (below 1.9 LPM) or no flow rate.

One Balston air filter (part number 300-01961) and eight valve manifold air inlet filters (part number 9981-123) are provided in the spares kit (part number 9982-072) and additional filters can be ordered from LI-COR.

Replacing the air inlet filter

Air filters are located inline with the tubing between each of the eight air inlets and the valve manifold.

Figure 7‑1. The air inlet filter is located inline with the tubing between each of the eight air inlets and the valve manifold.

The tubing is attached with barbed fittings found at the air inlet and the valve manifold. This provides a secure, long-term connection. A good way to remove the filter is to cut a small, wedge-shaped section out of the tubing behind the hose barb. Small, general-purpose diagonal, flush, or shear cutters work well. Position the cutters so that you will not scratch or damage the hose barb as you cut.

Caution: Using a knife to cut along the hose, across the hose barb is not recommended and should be avoided. Cutting across the hose barb may damage the sealing surface of the barb.

Figure 7‑2. Cut a small, wedge-shaped section out of the tubing behind the hose barb.

After cutting the wedge out of the tubing, pull the tubing firmly to the side (perpendicular to the fitting). The tubing will slide off with relative ease. Still, be careful to avoid injuring your knuckles when removing the tubing. Discard the old tubing and filter.

Figure 7‑3. Remove the tubing from the hose barb by pulling firmly to the side (perpendicular to the fitting).

Attach the tubing to the hose barb on the valve manifold. Pay careful attention to the orientation of the new filter. There is a raised arrow on the outside of the filter. This arrow should point toward the valve manifold so that the wider end is toward the valve manifold.

Figure 7‑4. Attach the tubing to the hose barb on the valve manifold with the wide end of the filter toward the valve manifold.

The tubing on the other end of the filter is longer than required. Route the tubing to the hose barb at the air inlet. Leave a little slack and trim the hose to length before sliding it over the hose barb.

Figure 7‑5. Route the tubing to the hose barb at the air inlet, trim the hose, and connect.

Replacing the Balston air filter

A blue Balston air filter is located between the valve manifold (inlet) and the system manifold (multiplexer) or pump (extension manifold).

Figure 7‑6. In the LI-8250 Multiplexer, the Balston air filter is located between the valve manifold and system manifold. Note the orientation of the filter and the direction of the flow.

To remove the air filter, press in on the orange collets of the quick-connect fittings on both sides of the filter. Pull the quick-connect fittings off and slide the filter out of the strap.

Figure 7‑7. Press in on the orange collets to remove the quick-connect fittings and slide the old filter out.

Slide the new filter into the strap. Note the direction of the flow from Figure 7‑6, and ensure the arrow on the filter is pointed with the direction of the flow. Then reconnect the quick-connect fittings to each side of the new air filter.

Figure 7‑8. Slide the new filter into the strap and reconnect the quick-connect fittings.