Operation and Repair Bulletins
The following documents are sections of our complete service bulletin set. These are available on our website Spectrawatermakers.com
MB-2 MEMBRANE CARE
Membrane life is affected by a large number of factors and is somewhat unpredictable. A |
|
big commercial plant running 24/7 will get 10 to 12 years out of a set of membranes. But |
|
they do all kinds of fancy chemical injections and never shut the thing off. Most cruisers are |
|
lucky to get five or six years out of one. You hear of the eight or ten year old membrane now |
|
and then. The biggest killers of membranes are lack of use, chlorine damage, and improper |
|
storage. |
|
Don’t let membranes sit around with sea water or stale fresh water in them. Biological |
|
growth will occur in the membrane. Here at the factory we frequently get back membranes |
|
for inspection that reek of hydrogen sulfide (rotten eggs). This odor is produce by anaerobic |
|
bacteria that live in an unused membrane, feeding on whatever animal or vegetable matter is |
|
trapped in it from the plankton that gets through the system. Membranes badly fouled in |
|
this way can seldom be saved. These bacteria are always present but are inhibited by the |
|
oxygen in sea water while the unit is in frequent use, by scheduled fresh water flushes, or by |
|
pickling. Keeping the prefilters clean is also important in preventing |
|
prefilters are allowed to become a breeding ground for bacteria (get smelly), the contamina- |
|
tion will spread throughout the system. When we cut open a failed membrane we also find |
|
mildew, another form of bio fouling, probably due to long term storage with no biocide or |
|
stale biocide. |
|
After many hours of water making mineral deposits will form and must be dissolved away |
|
with an acid cleaner. Alkaline cleaners are used for |
|
cially the alkaline, are not good for the membrane. Every time you clean the membrane it |
|
shortens its life. Clean only when necessary, and avoid cleaning as a “diagnostic tool”. |
|
Chlorine will destroy a membrane in minutes. It attacks the material that the membrane is |
|
made from. Always use product water or water filtered slowly through a charcoal filter for |
|
flushing and chemical treatments. |
|
Oil simply plugs up the matrix of the membrane and clogs it up. We have brought back oil |
|
fouled membranes with Joy soap (See |
|
For storage we recommend using propylene glycol potable water system antifreeze if avail- |
|
able. It can safely be left in the system for one year and will keep things from freezing in |
|
cold conditions. It is hard to find in warm climates, and takes up a lot of room on a small |
|
boat, so our |
|
Given good care a membrane will eventually just start to slowly fade away. The feed pres- |
|
sure may rise and/or the ppm go up. Hardly ever will they just fail overnight. |
|
8/13/04 | 44 |
|