Following are two possible reasons why enzymes may not be drawn from the reservoir.
1. The silicone tubes may be worn or flattened from use. To inspect the tubing, refer to TDF Service Procedure TS005 Tube Replacement (Pinch Valves) and reference the steps starting at step 11, related to performing a "Valve Test." The silicone tubes should be clear and fully opening. If any of the silicone tubes are excessively flattened or stuck in a pinched or closed position on their own (without the pistons pushing against them), then the tubes need to be replaced. A spare set of 3 1/4" silicone tubing that was originally sent with the TDF instrument. A set of 21 replacement tubes (3 1/4") can be ordered as TDF71 Pinch Valve Tubing Set by contacting ANKOM Technology at 1-315-986-8090 or order through the Product Catalog on this website.
It is recommended that all the pinch valve tubing be replaced at the same time to keep them on the same maintenance schedule (annually). This would include the IDF, SDF, and Waste pinch valves.
2. It is also possible that there is a blockage within the enzyme lines. Visually inspect the tubing from the enzyme reservoirs to the enzyme pinch valve to the manifold. If any crystals or dried enzymes are found, follow service procedure TS037 Enzyme Line Flush Procedure linked to below.
NOTE: It is recommended that when running methods AOAC2009.01, 2011.25 or 2017.16 that enzyme lines be flushed after every assay using this service procedure. If necessary, replace the enzyme supply tubing – see service procedure TS004 Tubing Replacement (enzymes).
To order an additional TDF67 Enzyme Tubing Replacement Kit contact ANKOM Technology at 1-315-986-8090 or order through the Product Catalog on this website.