Watermaid WM40 Owner's Handbook Manual - page 12
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(ii) SCALE FORMATION
If the pool surface is fibreglass, fibreglassed concrete, painted concrete, vinyl-lined, epoxy coated or
some similar inert surface, then scale can originate only from the water supply or chemicals which have
been added to the water and is therefore usually insignificant. If the pool surface is marblesheen,
pebbled, quartzon or tiled, then scale can originate from either the water supply, chemicals added to
the water or minerals that leach out of the walls.
It has been observed for many years, that salt chlorination Cells used in sea water conditions rarely foul
up with hard crystalline deposits. The soft mushy deposit in these cells can always be cleaned with a
strong jet of water or the use of a dilute acid solution.
By contrast, Cells used in marblesheen, pebbled, quartzon or tiled pools that have had calcium
hypochlorite (for hardness) or copius amounts of acid added, continually foul up and form deposits
that are hard, crystalline and difficult to clean. This can then stop the Cell from working within a few
days.
Scale is usually calcium carbonate, but can also include traces of other compounds. Sea water usually
contains roughly 1700 ppm calcium and 400 ppm magnesium, whereas many swimming pools normally
contain up to 400 ppm calcium but no magnesium. It has been noted that after the addition of
magnesium, to a level of about 20 ppm, Cells begin to mimic the sea water experience and the effect
can last some 6 to 9 months.
It is recommended that 25 Kg (55 lb) per year of magnesium chloride be added to the pool. All
25 Kg (55 lb) may be added to the pool at the one time. Magnesium chloride can replace all other
chemicals for any ‘hardness’ requirement.
It is also recommended that the calcium level in the water be not more than 120 ppm. A
calcium level above 200 ppm is considered excessive.
The use of chemicals containing calcium is NOT recommended for use with the
WATERMAID® WM40 chlorinators. These chemicals include calcium chloride ("calcium hardness")
and calcium hypochlorite ("granular/powdered chlorine").
Heavy scale build-up on the Cell electrodes can inhibit chlorine production, restrict water flow and
damage Cell beyond repair (voiding warranty). To rectify, the Cell will need to be cleaned manually and
the calcium level in the water reduced. To reduce the calcium level in the water, it may be necessary to
empty some of the water from the pool and top it up with tap water or collected rain water. The salt
will then need to be topped up to the appropriate level.
As each pool situation is different, the amount of build-up that is generated will also differ. It is
important for pool owners to maintain water balance(refer to section 10).
(iii) MANUALLY CLEANING THE CELL
1. Turn OFF the power to the chlorinator and pump. There is no need to disconnect the Cell from the
Power Supply when cleaning.
2a) For QT and XT series Cells, unscrew the white barrel nut at the top anti-clockwise and the
bottom clockwise to remove the Cell from the pipe work. Aim a strong jet of water into the Cell. If all
scale is removed successfully proceed to step 5, otherwise proceed to step 3.
b) For EZ300 Cells: If the mesh electrode is clean, then separate the electrodes by pulling the brass
plug out of its socket, unscrewing the barrel nut anti-clockwise and lifting the centre electrode out. Aim
a strong jet of water at the centre electrode to dislodge most of the scale, then use a rag to wipe the
electrode clean. Only the centreelectrode (being solid titanium) may be scraped clean. If all scale is
removed successfully, proceed to step 5.
If both the mesh and centre electrodes contain scale, leave the Cell electrodes intact and remove the
entire Cell by unscrewing the T-Piece Barrel Nut (refer to Parts View, page 8). Do NOT attempt to
clean the mesh electrode by abrasion. Proceed to step 3.
If the barrel nut is difficult to unscrew, the use of rubber gloves will give a better grip or pour some hot
(not boiling) water over it. A small amount of vaseline over the thread for next time may make removal
easier.
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4. AUTO CELL CLEANING
The WATERMAID® Power Supply is programmed to perform the following cycle:
1. Produce chlorine for 1 hour and 5 minutes, once water is flowing through the Cell.
2. Auto Cell Clean for 5 minutes (indicated by a blue flashing light).
3. A quick check for error conditions (indicated by a red flashing light).
4. Produce chlorine for 55 minutes and then repeat steps 2 - 4, until the WATERMAID® is turned off.
5. THE TIME CLOCK
1) Set the current time by turning the clock face in a clockwise direction so that current time aligns with
the arrowhead (top right of time clock).
2) Set the desired times for the chlorinator to switch on and off (refer to section 8 "Running Times") by
aligning the pins as follows:
For On settings, slide the pins away from the centre of the time clock.
For Off settings, slide the pins towards the centre of the time clock.
3) Now position the switch to the middle setting " " (for time clock settings).
N.B. If the time clock on the WATERMAID® Power Supply is different to the one pictured above and has
just two settings, only the "I" and "clock" settings will be applicable.
6. THE WATERMAID® CELL
(i) CHLORINE PRODUCTION
Each WATERMAID® Cell is capable of chlorinating a pool up to 120,000 litres (approx. 27,000 gal). The
recommended chlorine level is between 1 and 3 ppm for a pool, or between 3 and 5 ppm for a
spa. Chlorine production can be tested by taking a sample of water directly from the outlet flow. This
reading should be greater than elsewhere in the pool by approximately 0.5 ppm.
The expected life of a WATERMAID® Cell is 5-8 years. As the Cell wears out, less and less chlorine will
be produced.
Only a genuine WATERMAID® replacement Cell should be fitted, to ensure compatibility with the
WATERMAID® Power Supply model WM40.
*One revolution equals a 24-hour cycle.
*The time is in 24 hour time (e.g. 18=6pm).
*Each pin equates to a 15 minute interval.
It is recommended that a time clock be used to
control the pump, filter and WATERMAID®
chlorinator, and this may be internal or external
to the WATERMAID® Power Supply. For an
internal time clock, the 3 settings are as follows:
"I" setting = chlorinator will be ON permanently.
" " setting (position in the middle) - chlorinator
will operate according to the time clock's
programmed settings.
"O" setting - chlorinator is on standby.
TO SET THE TIME CLOCK
Turn OFF the power to both the WATERMAID®
chlorinator and pump so that both do not start
and stop erratically whilst the time clock is being
adjusted.
"I" Setting
"O" Setting
Arrowhead
" " or Clock
Setting
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