We used to...but now we don't (finally!)
Here was our rationale:
1. Our bays are heated.
2. If we're on scene, and we DON'T need the pump, we simply put it into gear and let it churn for as long as we're outside.
3. We HAVE had problems (when we used to drain the pump) with the DRAIN freezing open, and then we couldn't get it closed again to prime the pump!!
4. Simple physics. It's harder for a pump full of water to totally freeze up than it is for an empty pump with a little residual water to freeze.
We don't drain our pumps(anymore), but we do drain the lines(discharges and intakes).
It is dept policy to keep pumps drained during the winter months. I have never heard of a pump freezing, but have seen piping freeze on numerous occasions. it would be nice to do as some of you and drain only the outlets, but due to insufficent maitenence our pumps leak, so the outlets would only fill again eventually anyhow, besides some water in an outlet is worse then a full one anyhow as it can freeze, preventing gates from opening or closing
yes we drain our pumps because our pumper goes on runs that arent directly fire related (accidents, mutual aid with tanker and man power) so we drain discharges and intakes and pumps. in older trucks we put antifreeze in the pumps just to be safe we also put antifreeze on the threads so they dont freeze together.