Pumps and Heaters
Circulation Pump:
Your pool has a circulation pump that is responsible for moving pool water throughout the circulation system, (this is not to be confused with auxiliary pumps such as cleaner booster pumps, jet pumps, waterfall pumps, etc.). Water is drawn in from the pools outlets into the front of the pump, through the hair/lint trap, through the pumping chamber and out the top of the pool pump on its way to the filter.. Above ground pools and in rare cases inground pools have flooded suction pumps. These pumps need to be located below the pool water level because they are not capable of “pulling” a prime on their own and depend on gravity to keep them primed. The only maintenance for a circulating pump is to clean out the hair/lint trap basket as necessary and to lubricate the hair/lint trap lid gasket or o-ring with a non-petroleum based lubricant about once a month, (we recommend teflon or silicone based lubricants).
Determining what size pump is right for your pool: 5 Steps
1) Determine the number of gallons of water in your pool. The formulas for calculating the gallons depend on the shape of your pool.
For a RECTANGULAR POOL:
Measure the length (ft), the width (ft) and the average depth. The average depth is determined by adding the depth at the shallow end to the depth at the deep end and dividing by two.
The formula for calculating the total gallons in a rectangular pool is: Gallons = Length x Width x Average Depth x 7.5.
For example: your pool is 30 ft long and 15 ft wide. The pool's shallow end is 4 ft and its deep end is 8 ft. So, the pool's average depth is 4 plus 8 = 12 divided by 2. This gives you 6 ft. The pool's capacity is 30 ft x 15 ft x 6 ft x 7.5 = 20,250 gallons.
For a ROUND SWIMMING POOL:
Measure the diameter of the pool (the widest line straight across the surface) and its average depth. The average depth is determined by adding the depth at the shallowest part to the depth at the deepest part and dividing by two.
The formula for calculating the total gallons in a round pool is: Gallons = Diameter x Diameter x Average Depth x 5.9.
For example (see picture): your pool is 25 ft in diameter, the pool's shallow end is 3 ft and its deep end is 7 ft. So the pool's average depth is 3 plus 7 = 10 divided by 2. This gives you 5 ft. The pool's capacity is 25 ft x 25 ft x 5 ft x 5.9 = 18,428 gallons.
For an OVAL SWIMMING POOL:
Measure the longest diameter, the shortest diameter and the average depth. The average depth is determined by adding the depth at the shallow end to the depth at the deep end and dividing by two.
The formula for calculating the total gallons in an oval pool is: Gallons = Longest diameter x Shortest diameter x Average depth x 6.7.
For example (see picture): Your pool's longest diameter is 25 ft, shortest diameter is 15 ft and the pool's average depth is (3 + 7) / 2 = 5 ft. The pool's capacity is 25 x 15 x 5 x 6.7 = 12,563 gallons.
For a KIDNEY-SHAPED SWIMMING POOL:
Measure the largest width, the smallest width and the average depth. The average depth is determined by adding the depth at the shallow end to the depth at the deep end and dividing by two.
The formula for calculating the total gallons in a kidney-shaped pool is: Gallons = (Longest width + Shortest width) x Length x Average depth x 3.38.
For example (see picture): Your pool's length is 25 ft, longest width is 15 ft, shortest width is 10 ft and the pool's average depth is (3 + 7) / 2 = 5 ft. The pool's capacity is (15 + 10) x 25 x 5 x 3.38 = 10,563 gallons.
2) Determine FLOW RATE (GPH), determine how many gallons per hour (GPH) you need to pump to clean all the water in your pool in eight hours. FLOW RATE = divide your calculated gallons by eight. For the RECTANGULAR swimming pool example the GPH required is 20,250 gallons / 8 hours or 2531 GPH.
3) Calculate gallons per minute (GPM). To convert from GPH to gallons per minute (GPM), divide your GPH by 60 minutes (eg) 2531 GPH / 60 = 42.2 GPM. Having calculated your required GPM, you next have to figure out the average Feet of Head for your pool pump. Feet of head is the total of pipe length + valves and turns + filter and heater drag. For example:
Pipe lengths and rise = 28.0
Valves and turns = 4.7
Cartridge filter 70 sq. ft. = 7.5
Heater = 7.5
Total feet of head = 47.7
4) Select Pool Pump: You now have the information required to select the size of your pool pump. Go to the description page of the style of pump you would like to purchase. Many pump manufacturers will provide a chart on this description page showing the HP required for your particular GPM and Foot of Head. For example, based on the data calculated above for a typical RECTANGULAR pool, we are looking for a pump that will handle 42GPM with a 47 Feet of Head. According to the typical chart for 50 Feet of Head (closest to 47'), we need a pump between 3/4 HP (31 GPM) and 1 HP (50 GPM). Since we always go for the higher GPM, we would select the 1 HP pump.
5) The size of your pool filter is directly related to the pool pump you have selected. If your pool filter is too small for the pump, there will be additional strain on the pump motor as it tries to push water through and encounters resistance at the filter. This will eventually burn out the pump motor and your filtration will also be compromised. We recommend selecting the filter so that it is oversized to be absolutely certain it can handle the flow coming from the pump. So, in this case, instead of getting a filter rated at exactly 42 GPM, you should select one that is a little higher – around 60 GPM would be fine.
There are a couple of other considerations that should be mentioned in your selection of a pool pump. The above calculations are based on a basic pool configuration with no extra water features like: fountains, spas, waterfalls, solar heating, and in-floor cleaning systems. These features generally require higher GPM rates which equate to a higher HP pump.
Heater:
The typical pool heater is fueled by either natural or propane gas. Electric is an option but is costly and better suited for portable hot tubs. The pool water passes through the heat exchanger which is located in the fire box above the flame bed, thereby collecting heat from combustion and transferring it into the pool water. Pool heaters are lit either by electronic ignition or a pilot light and are controlled by a thermostat. A pool heater thermostat operates similar to an oven; you set the thermostat to the desired temperature and the heater turns on all the way and continues running until the desired temperature is reached, and then turns off, (note: a pool heater will only operate when the pool circulating pump is turned on). There is no routine maintenance for a pool heater other than to be sure no combustible material is on top of or leaning against the heater. Refer to the owners manual or contact a reputable service company for operating instructions and other safety precautions. The pool water then goes back to the pool via the returns.
Returns:
Pool water returns are places in the pool where water comes back in from the circulation system. A typical pool has two or three returns depending on the pool size. The return is usually a 1 1/2″ threaded opening that may have a directional eyeball that screws into it, (directional eyeballs are used to “aim” the water thereby enhancing proper water circulation within the pool).
Chemical Feeders:
Your pool may have an automatic chlorinator/brominator attached to the circulation system. Pool water is directed through the feeder where sanitizer is eroded (slowly disintegrates) into the pool water and sent back to the pool. The feeder should have a metering valve that adjusts the rate sanitizer is added to the pool. The only maintenance is to lubricate any cover o-rings with a non-petroleum based lubricant and add chlorine/bromine tablets as necessary.
Mineral Purifiers:
Your pool may have a mineral purifier, (Nature 2, Vision, Frog, etc.), that is plumbed in line within the circulation plumbing. Inside the purifier vessel is the cartridge that contains the purifying minerals; the cartridge must be replaced every 4-6 months. There is no maintenance with these units as the minerals sort of maintain themselves, however, there is a start-up procedure for new cartridges that must be followed using the manufacturers directions.
Cleaner Booster Pumps:
You may have an automatic pool cleaner that uses a booster pump to power the cleaner, the most common brand is Polaris. The pump draws water from the pool circulation plumbing and pushes it back to the pool via the dedicated cleaner line to which the automatic cleaner is connected. There is virtually no maintenance with this pump however it must not be turned on unless the pool circulation pump is running; the booster pump is not self priming and depends on the circulation pump to prime it and keep it primed.
Ozonators:
Some pools have an ozonator which adds ozone to the pool water somewhere in the circulation plumbing. Ozone acts to destroy organic waste and break down chloramines and bromamines. Some ozonators have a metering valve to control the air flow or ozone production. Follow the manufacturers directions for setting the flow rate. The ozone generation cell will eventually burn out and require replacement.