Mindray SC T240: distorted results at high sample load
What happened
In this case, once the number of samples in one run exceeded a certain level, results came out faulty with no error codes; at low workload the analyzer measured normally. The stirrer was also reported to stall or stop intermittently.
What was checked
- Check the pressure in the water storage tank.
- Run the lamp test to rule out the photometer side.
- Watch how the internal water container fills while the analyzer is under load.
- Assess the output of the water treatment system and the expansion tank.
- Inspect the inlet water strainer — in this case it was prone to clogging.
- Inspect the stirrer lift assembly for axial play of the shaft in the copper bushing.
Cause
The engineers considered it probable that the analyzer could not refill its internal tank in time: the water treatment system and expansion tank output was marginal, and refilling did not fit into the short cycle between measurements (about nine seconds, as reported in the case). The stirrer stalled, air entered the dosing system and spoiled the reactions, so results went wrong without any error codes.
The cause is probable and was not fully confirmed.
What was done
Recommended: add a second storage tank to build up a water reserve, clean the inlet strainer, and check the stirrer lift shaft for play (possible bushing wear). In a similar case on a Dirui 400, installing a second storage tank reportedly helped.
Safety
Isolate the analyzer from the mains before opening panels around the water path, treat all work on the fluid lines as biohazard work because the system carries patient samples, and pass the electrical safety test before returning the analyzer to service.
Lesson: Silent result distortion that appears only at high workload points to the water supply before anything else — compare the water treatment output and reserve with the analyzer's measurement cycle instead of chasing optics or chemistry.
Covered in the course: Lab Analyser Service — Level 2: Fault-Finding →
Written from an anonymised case shared by service engineers. It is not a manufacturer instruction and grants no authorisation. Independent note; names are trademarks of their owners.