TC 34 Submerged Pump

What flow and head is this rated for, and at what NPSH?

The listing does not provide flow rate, head, or NPSH specifications for this unit. TC34 pumps are typically rated for flow ranges between 100-300 GPM and heads around 150-400 feet depending on impeller configuration and operating speed, but you'll need to ask the seller for the actual performance curve and NPSH requirements for this specific configuration. The VFD allows operation across a range of frequencies, so rated performance at the motor's 102 Hz maximum should be confirmed along with the curve at typical operating points.

What seals, materials and drive does it have?

This is a seal-less submerged design where both pump and motor operate fully immersed in the cryogenic liquid, eliminating dynamic seals at the shaft. The unit has a 3-phase, 460V motor with Class F insulation rated for 55 amps at 102 Hz and a 1.00 service factor, driven by a VFD for variable speed control. Wetted material specifications (impeller, diffuser, shaft) are not listed; ask the seller to confirm whether construction is 304SS, 316SS, or another alloy, as this determines chemical compatibility and affects thermal conductivity in cryogenic service.

What should I inspect on a used pump before buying?

Request motor insulation resistance (megger) test results to verify the windings haven't degraded from moisture or thermal cycling, and check for any signs of liquid ingress into the motor housing. Inspect the impeller and diffuser for erosion, cavitation pitting, or cryogenic embrittlement cracks, and verify the shaft runs true without excessive radial play in the bearings. Ask for a recent performance test showing actual flow and head against the original curve, and if the unit includes the vacuum-jacketed sump, confirm vacuum integrity with a pressure rise test to ensure the low heat-leak design is still effective.