Dometic RO400 - Page 25

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Symptom
Possible error
codes
Check/Action Remedy
Alarm, too low pres-
sure due to a high
pressure drop in the
lters.
Alarm, too low
pressure due to
too low feed pres-
sure.
12
Has lter I been replaced?•
Can a high particle load be •
expected?
Is the coarse lter clogged?•
Check valves for inlet water •
before the water purier is
opened.
Measure the dynamic feed •
pressure using the special
service tool.
Is the water temperature •
high, thus resulting in a very
high capacity of pure water
production?
Is there reason to believe •
that the feed pressure varies
a lot?
Are there other users at the •
net that occasionally might
draw large amounts of
water?
Are there other lters, •
valves etc. installed prior to
the water purier that can
reduce pressure?
If lter I has not been changed or if the parti-
cle load is high, change lter I and try again.
If lter I has been replaced but the problem re-
mains, remove lter II. If this solves the issue,
install a new lter II. (It can also be concluded
that the inlet pressure sensor is OK).
Clean the coarse lter.
Booster pump
If the water pressure is frequently low, a
booster pump is a solution. Make sure that
lters, installed prior to the water purier, do
not add to the pressure drop.
Reduced pure water ow
A very high pure water ow will increase the
requirements of high enough feed pressure.
Therefore, it is possible to reduce the pure
water ow by an external valve. (It should not
be restricted too much if a accumulator tank is
used since this will result in on/off operation.)
Reduced working pressure
Reduce the working pressure by manipulat-
ing the pressure regulating valve. A decreased
working pressure will reduce the water ow.
The drawback is that there is no “pressure”
buffer. If, for example, feed water temperature
is reduced or if the membrane is scaled, the
ow will immediately go down. Normally, this
would result in an increased working pressure
and maintained capacity.
Accumulation of water
If the problem is due to an almost complete
absence of water, consider (for a short period
of time) using an accumulator tank - pres-
surised with a check valve or open tank
combined with a pump - that can provide the
product with water.
External low pressure shut-down
Use an external inlet pressure sensor at the
inlet side combined with a valve on the pure
water side that cuts the pure water ow when
the feed pressure is too low.
Temporary disconnection
As a drastic measure consider temporarily dis-
connecting the water purier at periods when
the water pressure is low. This will reset the
low pressure alarm. Note that if this is made to
frequently, the pump may be damaged.
TROUBLESHOOTING
c)
d)