Dometic RO400 - Comments

- 31 -
TROUBLESHOOTING
COMMENTS
1
The water ow is a function of temperature. A change of only
5 °C may change ow up to 20%.
2
Descaling will remove build-up of calcite and iron that blocks
the membrane. Descaling should be performed regularly to
avoid permanent damage to the membrane. Soft inlet water
will reduce the need for descaling.
3
A too low pump capacity usually due to faulty graphite
components in the pump.
These may have been worn out due to:
long service life, -
cavitation due to frequent low pressure operation, -
high particle load in the water, -
mechanical damage to the pump shaft. (e.g. transportation -
damage).
The pressure regulating valve controls the amount of water
recycled back to the inlet of the pump. If the pressure be-
comes too high, more water is fed back to the inlet to reduce
pressure. By manipulating the pressure regulating valve it is
possible to increase the system pressure.
4
If replacement of the pump does not help, it is possible that
the pressure regulating valve allows too much water to be fed
back to the inlet of the pump.
5
Remember that the water purier goes into ushing mode
after the water is turned off. The ushing may proceed for
several minutes depending on how long it has been producing
water.
6
The domestic models are equipped with a 15 minutes error
cut-out. This means that after 15 minutes of continuous
operation, the system will stop and alarm in order to protect
against leakages. The commercial models allow continuous
operation. To ensure a good water quality they perform auto-
matically an internal ushing after 15 minutes of continuous
operation. During this time, no pure water is produced.
7
The calibration of the water purier may have been done in
the wrong way, e.g. the calibration button was pressed at the
same time as the product was connected to power while the
faucet was closed. This recalibrates the outlet pressure sensor
instead.
8
The water quality measuring system includes a function to
ensure that lines etc. are not broken since this would errone-
ously indicate pure water. Therefore, if the system indicates
too pure water, it will alarm. This may happen if inlet water is
extremely pure and water temperature very low. Contact your
distributor for further information.
9
The motor capacitor provides a high enough starting power
to the motor. If the capacitor is broken, the motor will be fed
with electricity but will not have power enough to start.
10
All models are equipped with a leakage control sensor. It is a
oater connected to a microswitch. Therefore, it is important
that any spillage after service, lter change etc. is wiped off.
11
All models are equipped with inlet pressure sensor to protect
the pump from operation where a low pressure can cause
cavitation followed by damage to the pump.
12
Due to the high capacity of the RO400 models it may effect
the feed pressure if the net cannot supply sufcient amount of
water. It is therefore important to measure the dynamic feed
pressure (when the water purier is working) and not only the
static pressure. Preferably, the dynamic pressure should be
above 2 bar.
13
If the reject valve does not close properly, there will be a
continuously high ow in the drain hose > 2.5 l/minute when
water should be produced. (The reject valve remains in ush-
ing position).
14
If there is no water ow in either the pure water or the reject
hose, it could be because the inlet valve does not open. (If
water ows in the reject hose, the inlet valve open).
15
The inlet pressure sensor is recalibrated every time the prod-
uct is reconnected to power. If it is connected to fast after e.g.
a power failure, it is possible that the calibration is made at
a wrong off-set level. Therefore, wait for at least 60 seconds
after disconnection before the product is reconnected to allow
the inlet pressure to come down.
16
All models measure the conductivity of the pure water. This
value is compared to a preset value determined at installation
(the calibration procedure). If the inlet water quality or tem-
perature has changed a lot - the calibration is invalid.
In a hot climate or when piping is effected by the sun, the
temperature can temporarily rise. By ushing the product,
cold water is allowed into the system.
17
If the ushing does not work properly, salt will accumulate
in the membrane and result in continuously reduced water
quality.
18
A low pump pressure should also be connected to a low ow.
If a low ow is not a problem, the pump pressure should not
be the cause. If the water ow is also low (total ow of reject
and pure water < 5.5 l/min) the pump pressure should ap-
prox.15 bar.
If the pump pressure is too low it may take an extended period
of time before the sufcient purication level is reached. If it
takes more than 30 seconds, the water purier will stop au-
tomatically. If the product is restarted again, it will probably
reach the purication in the next attempt.
19
If the recirculation ow does not function properly the con-
ductivity will gradually increase in the permeate. The reason
is that absence of recirculation causes a build-up of salt along
the membrane that is not removed.
20
It is normal with some sound from the product. Since the
ushing starts automatic it may start in the night. If the prod-
uct is built-in this sound can be magnied.
21
Low inlet pressure leads to cavitation in the pump, followed
by a very distinct squeaking sound. Normally the low-pres-
sure protection will shut down the product before this takes
place. However during start-up there is a time were the low-
pressure is deactivated and also the inlet pressure sensor may
be broken