Discharge door leaks grout or does not close
Symptom
Grout drips from the closed door during mixing, the door does not close fully, or the closed door slowly drops.
Likely causes
- Worn, torn or hardened door seal.
- Hardened concrete on the door edge stops it closing fully and cuts the seal.
- Low hydraulic closing pressure, internal cylinder leak or leaking check valve.
- Position switch dirty or bent, so the door is not driven fully closed.
Most likely and cheapest to check first.
Checks
- Clean the door edge and seal surface, then watch one batch.
- Read the closed pressure on the gauge and compare with the value on its label.
- With the pump off, watch whether the closed door slowly drops.
- Check the position switch arm or proximity sensor for concrete and damage.
Fix
- Clean the door edges, seal and switches every shift.
- Replace the door seal when it is torn, hardened, or when cleaning no longer stops the leak.
- Reseal the cylinder or replace the check valve if the door drops.
- Fit a cover over the switch so concrete cannot hit its arm.
Stop the equipment if
A heavy leak, or a door that will not hold closed under a full batch.
Parts you may need
A door that leaks costs every batch
A door that does not fully close leaks cement paste and water during mixing. The batch loses fines, the concrete is out of specification, and the leak hardens on everything below the mixer.
Most door faults come from four things: a worn door seal, hardened concrete on the door and its edges, the hydraulic (or air) system, and the position switches.
DANGERRelease hydraulic pressure and pin the door before working on it. A door under pressure or gravity can close on a hand.
FIELD TIPTest the manual emergency pump once a month with an empty mixer. A hand pump that has never been used is often stuck the day you need it.
FIELD TIPJog the door open and closed before production every day and confirm both position signals. Wash the door and its edges every shift so set concrete cannot jam it.
⚠ Every check inside a machine starts with full lockout. Safety disclaimer