|Pumps and sumps.
||[Feb. 13th, 2013|08:59 pm]
Got around to testing the cellar pump today. Wow! It's fast, 20 liters in the blink of an eye. However, I sort of assumed there would be a non return valve in the pump because otherwise, if you're using a float switch, once the level falls the pump switches off and the water in the delivery pipe runs back, raising the level again then the pump starts again, stops again, starts again... and so on. I can imagine the whole kit shaking to bits with 11 liters (I measured it) chugging up and down the pipe, conceivably for hours. So the answer would be fit a valve. Not so simple, just try buying one! Eventually I found one at an on-line chandlers after using a bit of lateral thinking along the lines of "where else would one use a valve like this". I took the opportunity to calculate the capacity of the sump (35 liters) to check there would be enough capacity in the system. There was a "d'oh" moment when I realised I hadn't allowed for the displacement of the pump, but who hasn't done that when calculating sump capacity?
All this and I hope I never need the pump. Seems a shame really, maybe I should flood the cellar every so often just to feel smug about having the foresight to install the system. On second thoughts, I should finish installing the system before feeling too smug. Just waiting for a diamond core drill bit to arrive so I can route the pipe out through the garage, back in the house via the bathroom and out into the drain.