For some reason my reply to you was broken in half by something.
I will try again.
Maybe I misunderstood your earlier email where you said, "...water is pumped through the system and out through the hull..." The pressure valve is designed to increase pressure to the outside of the membranes by restricting the outflow...thus increasing pressure. It is actually very simple.
I would not run the water maker until you find the source of the problem which could be:
- Source of saltwater is restricted by a closed valve, clogged prefilter(s), clogged line, supply pump (sometimes referred to as low pressure pump), not working or clogged.
- Failure of the HP pump, which could be failed ceramic pistons, cracked head, or loose head (I had this "loose head" thing happen to me...bolts loosened and no pressure...tightened them up and all was good).
- Failure of the connection between the motor and the HP pump
- Dump valve stuck open (if you have this...I think newer systems do).
- Pressure adjustment valve not working correctly...i.e. not actually closing to increase pressure.
Some of your other questions:
Yes, a carbon filter will remove chlorine. I have seen many water maker installations with a carbon filter in-line with the flush line. I do not know why this is not standard on the Dessalator systems. The Dessalator Manual says: "Please note that the drinking water produced by your reverse osmosis system is essentially sterile, however, your fresh water storage should be treated periodically with chlorine or iodine to ensure it remains consumable. Pay attention not to allow chlorine into the desalination system, as this could damage the device."
I am not sure how Dessalator assumes that we "not to allow chlorine into the desalination system without a carbon filter to block the chlorine.
Regarding fresh water being a problem for membranes, I disagree and don't think so...the manual states:
The membranes should be permanently immersed in liquid, either sea water before treatment, fresh water provisionally stored or sterilizing liquid, if the desalinator is not used for extended periods of time (Sterilizer is effective for six months and must be replaced after this period of time).
I believe the two biggest enemies of the Dessalator system are:
- Dried membranes
- Sterilizing or Cleaning chemicals (same chemical, but Dessalator uses both terms)
- Overdosing Sterilizing or Cleaning chemical. I think that if you absolutely have to do this, use 50% of the quantity of chemical and do not leave the chemical in the membrane tubes, but rather flush with tank water for 15 minutes. The chemical is caustic!
Flushing regularly and after each use, or a minimum of once a week---for 6 minutes, with tank water, and using a carbon filter to block any chlorine is the best thing you can do.
All that said, I am no expert. My knowledge has been gained through years of sometimes costly experience.