Pool Heaters
In this article we will explore several aspects of pool heaters.
1. The type of pool heaters that are most common and which is best for your home.
2. Facts about warranties that you need to know
3. The basic operation of heat pump pool heaters.
Type of pool heaters
The 2 most common pool heaters are gas type (Natural or LP) heater or heat pump.
Gas heaters will heat a pool or spa much faster and will operate at any outside temperature. This type makes sense if you desire heated water on demand but is more expensive to use on a day to day basis.
Heat Pumps are the most energy efficient and the least expensive to operate if you need hot water on a continuous basis. They do not heat the water quickly and will not operate if the temperature falls below the 45-55F degree range.
Warranties
One of the most important items to check when you purchase a new pool heater is the warranty. Not all warranties are the same. Special attention should be given to the warranty coverage on the compressor, coil, and the heat exchanger. Another important aspect of the warranty is items that might void the warranty. Some manufactures void the warranty if ownership changes. Some manufactures do not honor the warranty on the heat exchanger if they determine that the damage was caused by a chemical imbalance in the pool.
How do they work?
A heat pump is just an air conditioner working in reverse. Heat pumps use the heat out of the air to heat the pool water. The refrigeration cycle is just reversed. There is heat content in air all the way down to -460f or -273C. Through the process of refrigeration the heat can be removed from the outside air and be transferred through the heat exchanger to the water. It should be noted however that when the outside temperature drops below 50f, the heat pump looses too much efficiency to heat the pool. Most manufactures size for a 2-6F input per filtration cycle. For weekend use, it is actually more economical for a user to maintain the water temperature at or near the desired temperature and then boost the temperature 12-24 hours before he expects to use the pool.
Heat pumps are designed to be almost maintenance free, but just as you have your air conditioner checked out yearly; you should also have your pool heater, gas type or heat pump type checked once per year by a qualified air conditioning contractor.
While most people in the industry think of heaters in terms of electric or gas fired varieties, a growing number of pool owners are opting for energy efficiency and money savings offered by a heat pump.
To begin with, a heat pump is just a refrigerator working in reverse. Instead of taking the heat out of the available air, heat pumps use the heat from the air to heat the pool or spa water.Both heat pumps and refrigerators use an extremely cold, liquid chemical called Freon, which at normal air pressure boils at something like -47 degrees Fahrenheit. Actually, in the pressurized system of a heat pump, the Freon boils at around -41F.
In the case of a heat pump used in a swimming pool application, the heat laden gas freon is pumped into the compressor, where a pressure of about 225 PSIG is applied. At that pressure the temperature the Freon rises to around 125F. The hot gas is then pushed through a water heat exchanger, where its heat is transferred to the water. Then the gas is depressurized. It loses temperature, returns to being a liquid and is ready to go through the whole process again.
Heat pump swimming pool heaters are not meant to heat pools quickly. Most manufactures size for 2-6F input per filtration cycle. For weekend pool use, it is actually more economical for a pool owner to maintain the water temp. At or near the desired temp. and then boost the temperature 12-24 hours before he expects to use the pool.
During cooler weather, water temperature can drop 5-8f overnight. Even if the heat pump is shut down for only a few days during these cool spells, at start up, it will take a day or two for the heat pump to bring the desired temperature. If the pool will not be in use for a month or more, the heat pump should be shut off or down a few degrees.
A heat pump pool heater is designed to maintain a constant water temperature. It is not intended to raise the water temperature quickly.
Heat pump pool heaters are designed to provide comfortable pool temperatures (80F or higher)when outside temperature is 50F or higher. Because they are not designed to heat a pool quickly, if a period of sustained cold weather is followed by a day or two of warm weather, chances are that the pool heater will not be able to heat the pool fast enough to take full advantage of the short warm period.
Heat pumps are designed to be relatively maintenance free, however just as you have yearly maintenance performed on your air conditioning system, regular inspection and maintenance of your heat pump pool heater will promote the highest operating efficiencies. Likewise, a properly maintained heater will protect your investment, and will potentially extend the useful life of your heat pump.
