INSTALLATION OF GRP PUMP CHAMBERS
Ready-built package pump stations are simple to install, and given a little
common sense, can be completed quickly and easily without previous experience.
The following guidelines are intended for installation of pump chambers with
fitted covers, suitable for pedestrian weight only. Where chambers will be
subjected to heavier weight loadings, it is necessary to construct a suitable
reinforced cover over the chamber.
Where there is a high water table or a possibility of the ground becoming
saturated, it will be necessary to encase the chamber in sufficient weight of
concrete to prevent floatation. It may also be necessary to fill the chamber
with water and/or dewater the site while the chamber is being installed.
For general installations where there are no structural or water table
considerations, proceed as follows:-
- Excavate site approx 100 mm deeper than the chamber
- Pour a concrete bed in the bottom of the excavation and install the pump chamber onto the bed. The sides of the chamber must be vertical and the manhole cover must be exactly at floor or ground level. Ensure that the discharge is pointing in the correct direction.
- Partially backfill with concrete.
- Connect the discharge pipe to the outlet connection.
- Position the incoming pipe(s) and cut a hole in the chamber with a hole saw or jig-saw. Fit the pipe(s) and seal around the pipe with silicone sealant.
- Install the cable ducting and connect to the cable inlet position on the chamber. Leave a draw cord in the cable duct.
- Backfill with concrete around the chamber approx 100mm thick.
- Reinstate the floor or ground around the chamber as required.
- Install pump(s) and level control floats, and pull cables through duct to power supply/panel position.
- Electrical installation should be carried out by a competent electrical engineer.
FLOAT SWITCHES
- For systems using float switches, they will need to be fitted after installation. It may be necessary to make final adjustments after the system has been put into use.
- For pumps with built-in floats, there is not usually any need to carry out any adjustments. The float is double acting and switches the pump on and off. Adjustment is usually possible by repositioning the float cable in it’s holding clamp.
- If an additional high level alarm float is being used, it should be set between the switch-on level and the incoming pipe.
- Most twin pump systems use 3 floats. The connection positions will be
clearly marked in the control panel. The following is a guide to where they
should be positioned in the chamber.
- Bottom float switches the pump(s) off. It should be set to activate when the level reaches around the mid point of the pump.
- Middle float starts the duty pump and should be set around 250mm below the incoming pipe.
- Top float starts the standby pump and activates the alarm. It should be set just below the incoming pipe.
- After the system has been put into use, check and re-adjust if necessary.
- For single pumps which have a separate alarm system, it is a good idea (where possible) to provide the pump and the alarm with power from separate circuits. This will enable the alarm to operate if the pump trips the circuit breaker.