ZWL Direct-Coupled Self-Priming Sewage PumpCold-Weather & Freeze Protection for a ZWL Pump
A self-priming pump holds liquid inside — which can freeze in winter. Here’s how to protect a ZWL pump in cold weather so it primes when you need it.

The DN65–DN100 ZWL self-priming pumps are the workhorses of the range — flow to 100 m³/h, head to 80 m. Models, ratings and typical uses.
| Flow Rate | 8–800m³/h |
|---|---|
| Head | 10–80m |
| Power | 1.5–75kW |
| Inlet / Outlet Diameter | DN25–DN300 |
| Material | Cast Iron,SS304,SS316L |
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If there’s a “sweet spot” in the ZWL range, it’s the middle. The DN65 to DN100 ZWL direct-coupled self-priming sewage pumps cover the flows and heads most real jobs land on — which is why these are the models we quote most often.
This band spans a wide spread of duty points on 4–45 kW motors:
So within one port size you can pick low-head/high-flow or high-head/lower-flow — handy for matching a specific site.
These are the go-to pumps for municipal sewage stations, factory effluent, farm and aquaculture duty, and general industrial drainage. They pass solids up to about 60% of the port diameter (roughly 48–60 mm) and long fibre, self-prime with no foot valve, and come in cast iron or stainless steel to match the medium.
ZWL Direct-Coupled Self-Priming Sewage PumpA self-priming pump holds liquid inside — which can freeze in winter. Here’s how to protect a ZWL pump in cold weather so it primes when you need it.
ZWL Direct-Coupled Self-Priming Sewage PumpWhen one pump isn’t enough or downtime isn’t an option, ZWL pumps run in parallel or duty/standby. Here’s how to set that up sensibly.
ZWL Direct-Coupled Self-Priming Sewage PumpWhich ZWL pump parts wear, and which spares to keep on the shelf? A practical guide to impeller, mechanical seal, sealing ring and bearings.