Does Lachat have a procedure for back flushing six port injection valves?
Valve back flushing.
The following steps can be followed to try and back flush the QC8500 valve assembly (Product # 85079) and remove a clog.
- Verify pump tubes for the autosampler are clamped down and the pump is running. This is typically a green pump tube (goes to sampler probe) and a purple pump tube (goes to wash bath). If both lines are pumping, the water from the sample line can be used to flush. This also assumes the autosampler probe is down in the wash bath, or other water source, so that it will be pulling water.
- To back-flush the valve, to clean it out, first remove the sample loop which goes from port 1 to port 4.
- Use the sample line for back flushing. It may help to put some paper towels next to the open port to absorb the water that should flow freely.
- With the sample loop removed disconnect the tubing from port 5.
- Disconnect the sample line from port 6 and then plug it into port 5. Water should come out of port six.
- The max speed option on the pump can be used to give it a good flush.
- Manually toggle the valve.
- While flushing, go to the timing tab within the run properties window. There will be boxes in the upper right hand corner. These allow one to toggle the valve back and forth. If working with the valve on channel 1, click on the box labeled 1. If working with the valve on channel 2, click on the box labeled 2, etc. When the box shows a green pathway the valve is in the inject position and the water will come out of port six. When the box shows a red pathway the valve is in the load position and the water will come out of port four.
- By switching the valve back and forth, it may free up something that needs to be flushed out.
- Repeat this for port 3 and port 1.
- Hook up the line from port six to port 3 and/or port 1 and do the same flushing.
- When finished, hook the lines back up to normal again, which is sample loop between port 1 and 4, sample into 6, waste out 5, carrier into 2, and port 3 is out to the manifold.