21
DRISTEEM RO 200 SYSTEM WATER TREATMENT SYSTEMS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
MAINTENANCE
Maintenance continued
WHEN TO CLEAN OR REPLACE MEMBRANES
In normal operation, the membrane in reverse osmosis elements can become
fouled by mineral scale, biological matter, and grime. These deposits build
up during operation until it causes loss in water output or loss of salt rejection,
or both. Elements should be cleaned or replaced whenever the water output
rate drops by 10 percent from its initial fl ow rate (the fl ow rate established
during the fi rst 24 to 48 hours of operation) or when TDS in the product water
(permeate) rises above 50. This is indicated through a message on the Vapor-
logic controller (above 75 will alarm).
It should be noted that the water output rate will drop if feed water temperature
decreases (about 1.5% per °F). This is normal and does not indicate membrane
fouling. A malfunction in the pretreatment, pressure control or pump can cause
a drop in feed water delivery pressure, feed water fl ow, product water output,
or an increase in salt passage. If such adjustments are needed, the element
may not require cleaning.
REPLACING MEMBRANES
TOOLS
• Rubber mallet
• Flat blade screwdriver
• Open end wrench,
⅞
inch
• Safety glasses
PROCEDURE
1. Turn OFF the RO system.
2. Relieve pressure on the membrane by opening the supply valve.
3. Remove all lines from the top of the pressure vessel(s). Make sure the
fittings are marked so the fittings go back to the correct locations after
replacing.
Note: Membranes on RO system are removed and inserted from the top.
4. Remove end plugs by pulling carefully. See Figure 21-2.
FIGURE 21-1: PRE-FILTER
1. Sediment filter:
Removes sediments and particles down
to 5 micron size.
2. Carbon filter:
Primarily to remove chlorine; also
removes organics and sediments down
to 10 microns.
FIGURE 21-2: DRISTEEM REVERSE
OSMOSIS MEMBRANES
1
2
2
