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Pool Heater Checklist

Your pool heater is the most expensive piece of equipment on the pad - make sure your heater is protected against early failure by following this pool heater checklist! If you are looking to replace your heater then be sure to read the pool heater reviews by Swimming Pool Steve.


Pool Heater Water Chemistry

The most important factor that will determine how long a pool heater will last is how well you balance the chemicals in your pool. Chronic imbalance of water chemistry values can ruin in a heater in a single pool season if they are bad enough so great care should be taken to learn about how to balance your pool water. If you think that you might need to brush up on your pool water chemistry then you should read the Pool Chemistry Crash Course.

Chlorine levels that are too high will corrode the internals of a gas heater, calcium that forms on metal components will deteriorate them rapidly, and pH that is too low or too high will destroy them faster than any other way. You can see now how your heater is subject to advanced decay from multiple water chemistry variables - imagine if all of these values are not within balance just how fast your heater can become damaged. Heaters that have been destroyed from chemical damage will have obvious signs on chemical damage inside and most manufacturers will not honor heater warranties for products that show chemistry related damage.


A pH level of 7.0 is 10 times more acidic than a pH of 8.0
A pH level of 6.0 is 100 times more acidic than a pH of 8.0
A pH level of 5.0 is 1000 times more acidic than a pH of 8.0


Understanding that the 0-14 pH scale is logarithmic it is easy to see how having your pH out of balance creates a drastically more corrosive environment for the heater. Compound this over the life of the heater and pH imbalance is easily responsible for most pool heater failures.


Pool Heater Bonding

The most likely way that your heater is not installed correctly would be the absence of a bonding wire connected to the casing of the heater. This bonding wire is in place to protect against galvanic corrosion, which is a major cause for early pool heater failure. While some pool companies do bond pool heaters, most existing swimming pool heaters are not bonded at all which will absolutely reduce the service life that you will get from it.

For more information on bonding for pool heaters you can read about it on the pool heater reviews page. If you want to make sure that your heater is protected as much as possible then you can look at your heater to see if there is a bare copper wire connected to the casing of the heater somewhere. In the USA it is common to use #8 copper wire and #6 is commonly used in Canada for bonding purposes. The bonding wire should be part of the bonding loop, which is a heavy gage copper wire that is connected to every metal component both in and around your swimming pool. This bonding wire is then grounded to the main ground panel of your house effectively tying all metal components of the pool to the same electrical potential. This video highlights a pool that is missing the bonding wire from the heater and shows where the bonding lug is located so that you can go and inspect yours.

If you do not bond your heater then the salt water combined with differential metals within the heater will act as a self contained primary battery. Small electrical currents will travel in between differing metals which will cause an advanced rate of decay in the weaker metal as it becomes the anode in a galvanic couple. By bonding the heater you are forcing the electrical potential of the metals to be at the same potential which prevents the ability for current to flow between the metals. If there is no potential difference (voltage) between the metals then there can be no current transfer.





Pool Heaters & Salt Water Chlorine

If you have a salt water pool then you absolutely, positively must have a check valve in between your heater and your salt cell. This is an extremely common problem in the pool industry currently and if you have a pool heater and a salt water chlorinator then there is a very good chance that you are missing something crucially important - a check valve.

A salt water chlorine generation cell must be installed downstream from a pool heater. This is due to the chlorine being generated in the cell being both very corrosive as well as very concentrated. If you were to allow concentrated chlorine into the pool heater this would obviously be undesirable - and this is in fact exactly what is happening if you do not have a check valve on your system. A check valve is a one way valve that when installed between the salt cell and the heater will prevent concentrated chlorine from traveling backwards through the pipe and pooling inside the heater. This is most commonly a problem for the periods of time that you turn the pump off. The chlorine still generates for a few seconds after the pump ceases and this concentrated cloud will float directly into your heater unless you prevent it. This video highlights a pool that has a check valve in between the heater and the salt cell.


Pool Heater Failure

Whether from chemical damage or from galvanic corrosion, one way or another corrosion is likely to be the death of your heater one day - you should take every step you can to prevent this from happening. A sacrificial anode is something that you can install that will drastically reduce the potential for damage to your heater from galvanic corrosion. Every swimming pool should have a sacrificial anode installed to reduce the risk of damage to metal components within the pool. If you have a gas heater it is even more important - if you have a gas heater as well as salt water you would be absolutely crazy to not have a sacrificial anode installed. The only real question is how did nobody ever explain this before?

Galvanic corrosion is confusing and not many pool technicians are knowledgeable about it, what it does, or how to prevent it from damaging your pool. As a result most pool owners are never made aware of sacrificial anodes or how incredibly important they are. Since you have salt in your pool (chlorine is made from salt) as well as dissimilar metals in your pool, then effectively you have a galvanic couple between differing metal components. By adding a sacrificial anode to the system a new metal is introduced that is weaker (less noble) than the other metals. This new introduced anode will take the brunt of the damage from galvanic corrosion and all you need to do is simply replace the zinc rod every 3 years on average. That is a much better option that replacing your heater once every three years!




A pool sacrificial anode like this will last 3 years on average before needing replacement. You simply replace the zinc insert with a replacement anode.

If you have a heater that has failed be sure to read the pool heater reviews by Swimming Pool Steve to see all brands, makes and models of pool heater compared side by side. Follow the tips on this page to make sure it last as long as possible for you!





Tips For Installing Swimming Pool Heaters

Before you attempt to install any swimming pool equipment you should take a look at the video series from Swimming Pool Steve that reviews installations of pool equipment for deficiencies. Additionally there are sections on pipe materials, plumbing fittings, glue, primer, unions and valves commonly used for installing pool and spa equipment. If you would like to learn more about how to install a pool heater correctly as part of a pool system read the Installation Tips from Steve.