Page 44
ENGLISH
Jandy
®
Pro Series, JXi
™
Gas-Fired Pool & Spa Heater
|
Installation & Operation Manual
Section 12. Water Chemistry
Proper Water Balance is the key to the enjoyment of your
pool or spa experience and to the long life of your heater.
The pH of your pool or spa’s water is one of the factors
that has the most impact on indicating how properly
balanced the water is. The other factors are: temperature,
total alkalinity, calcium hardness and total dissolved
solids. Cold water is typically more acidic (corrosive),
while hot water that is not properly balanced could lead
to a scale forming (basic) condition. While the heater is
in operation, if the PH is allowed to rise above 7.8 and
the calcium hardness and total alkalinity are not properly
maintained; calcium in the water could lose solubility,
coating the copper tubes inside the heat exchanger.
This will restrict the flow of water resulting in reduced
efficiency and possible damage to the heater.
If the pH is allowed to drop below 7.2, and the alkalinity
is not properly maintained, the water will become more
acidic. Acidic water has a tendency to dissolve metal
components in the pool plumbing with the copper heat
exchanger in the heater being a prime target.
PH, Total Alkalinity (TA), temperature, Calcium Hardness
and Total Dissolved Solids (TDS) play a role in whether
the water is either corrosive or scale forming. These
factors are combined in the Langelier Saturation Index,
which is a method for determining whether or not water is
properly balanced. See Table 7 below.
Table 7. Water Saturation Index
Saturation Index = pH + AF + CF + TF -12.1
A-Factor=(AF), C-Factor=(CF), T-Factor=(TF)
Total Alkalinity Calcium Hardness
Temperature
A-Factor
C-Factor
T-Factor
PPM
Factor
Value PPM
Factor
Value
°F
Factor
Value
5
= 0.7
5
= 0.9
32
= 0.0
25
= 1.4
25
= 1.0
37
= 0.1
50
= 1.7
50
= 1.3
46
= 0.2
75
= 1.9
75
= 1.5
53
= 0.3
100
= 2.0
100
= 1.6
60
= 0.4
150
= 2.2
150
= 1.8
66
= 0.5
200
= 2.3
200
= 1.9
76
= 0.6
300
= 2.5
300
= 2.1
84
= 0.7
400
= 2.6
400
= 2.2
94
= 0.8
800
= 2.9
800
= 2.5
105 = 0.9
1000 = 3.0
1000 = 2.6
128 = 1.0
A saturation index of 0 is perfectly balanced
A negative saturation index has corrosive tendencies
A positive saturation index has scaling tendencies
A saturation index of +0.3 or -0.3 should be used for visible,
cosmetic pool surfaces.
NOTE
Acceptable “saturation Index” is b0.5 and
-0.5. When dealing with a cosmetic surface the
index should be maintained b0.3 and -0.3.
A positive value is more acceptable than a negative
value.
The practice of putting tablet-based sanitizers in the
skimmer basket can produce heavily chlorinated water
with very low pH in contact with metal parts of the heater
that can cause serious damage. Practices like this should
be discontinued and the use of floating sanitizer dispensers
and check valves as backflow preventers with inline
erosion-style feeders should be encouraged.
If acidic conditions are present, there could be signs of
metal in the pool water that could cause staining on the
floor of your pool. This might manifest itself in the form
of brown stains on the finish of your pool bottom or pool
water discoloration. Your local pool dealer can test for
metals in your water or can provide you with a test kit.
Every effort should be made to maintain the water balance
of your pool or spa in the proper range. Ignoring this very
important component of your pool’s water chemistry can
make the water less enjoyable to bathe in and result in
permanent damage to your heater and/or complete failure
of individual components.
Zodiac Pool Systems does not warrant heat exchangers
damaged by corrosive water issues or from the build-up
of calcium in the heater’s heat exchanger. Any questions
regarding proper water balance can be directed to our
product support line at Zodiac or to your local pool dealer.
NOTE: The Thermal Regulator Valve (TRV) is an indicator of
how well the water chemistry is being maintained.
The TRV Should be inspected before each
pool season to ensure it is clean and operating
properly. If you see signs of calcium buildup or
corrosion the TRV should be replaced and your
water balanced.
