Knowledge centre
Draining a flat roof or cellar without overheating
2026-03-18
Set-up, hose choice, the top outlet and the mistakes that kill pumps fastest.
Start with the right spot
Put the pump at the lowest point, not in the middle. On a flat roof that is rarely where you expect: watch where the water collects first.
On gravel or rough membrane, place a flat slab under the pump so the suction side stays clear.
Hose and couplings
The top outlet has a 3-step adapter (1" – 3/4" – 1/2"). Work at the largest size you can: every reduction costs flow.
A 25 m flat roll-out discharge hose (article 6014734) is the classic pairing. Lay it without kinks and without needless height gain.
The supplied check valve stops the hose draining back into the pump when it stops.
Do not run dry longer than needed
The SIMER tolerates dry running longer than most pumps thanks to its water-cooled housing, but not indefinitely. Switch off once the floor is merely damp.
If thermal protection trips, let the pump cool instead of restarting immediately.
What not to do
No sludge, mortar or leaves: the SIMER is built for clean water with particles up to 2 mm.
Never lift or lower the pump by its cable. The cable is replaceable, but a torn one costs you a working day.
SIMER is a brand of Contimac GMT International — contimac.beEnabling craftsmanship since 1988