Viron Pool and Spa Heater Page 5
CHEMICAL BALANCE
It is imperative that correct chemical balance be maintained in your pool and spa water, otherwise
corrosion of your heater may occur. Corrosion of the heat exchanger voids warranty. Your
local pool shop specialist or spa retailer can advise correct chemical balance. Your water should
be checked and maintained regularly by a pool water professional. As a guide the following
parameters may be used.
pH 7.6 to 7.8
Total Alkalinity 80 to 120 ppm
Calcium Hardness 150 to 250 ppm
Salinity 4000ppm max. Excessive salt can damage your heater.
You should test your water chemical balance at least on a weekly basis.
Excessive sanitiser can damage your heater. Chlorine should not exceed 3 ppm and bromine
should not exceed 5 ppm. Salt chlorinators, especially when used on spa pools or indoor or
covered pools, can easily produce excessive chlorine levels which will damage the heater
internals.
CORROSION PREVENTION IN HEATERS
All pool and spa heaters use copper or copper nickel to make their heat exchangers as it is the
most efficient material in transferring heat from the combustion chamber into the water. The
typical life expectancy of a well maintained pool/spa heater is between 5 and 12 years.
The addition of sanitisers (Chlorine, Bromine etc) and other water balancing and conditioning
chemicals can increase the rate of wear and tear on the heat exchanger and associated parts in your
heater.
There are three most common reasons for heat exchanger corrosion which can be avoided with a
little care and attention.
1. Excessive Sanitiser. This means too much Chlorine or Bromine in the water. Be careful, if
the level of Chlorine or Bromine is excessively high your test kit (and the pool shops) may not
read accurately or indeed may show a nil reading. Any time a salt chlorinator is operating for
extended periods, (when heating the swimming pool from cold), particularly if the weather is
overcast or the pool enclosed or covered, the Chlorine level may exceed normal levels. When
heating a Spa Pool, turn the chlorinator down or off for the duration of the heating period.
2. Out of balance water. The water balance is a combination of pH, total alkalinity, Calcium
hardness and temperature. Balanced water will help prevent corrosion of your heater. Balanced
water should be between 7.2 - 7.8 pH.
3. The addition of acid to lower pH. Acid must always be added in small quantities and spread
over the pool surface evenly, not added in to the skimmer. Do not add a litre at a time, add a
cupful each day to lower your pH.
If you have a salt chlorinated INDOOR pool or COVERED pool be very careful of the level of
Chlorine being produced. If you use a salt chlorinated spa be very careful of the level of Chlorine
as the Chlorinator is usually sized for the pool and therefore should be switched off when heating