Coates has been the name to trust for quality and reliability in water heating equipment since the 1940s and continues to lead the industry in quality and performance across their entire line of swimming pool heaters. Their pool heaters are available from 1.5kW to 57kW and most can be ordered in single or three phase models. For large commercial applications they also offer heaters up to 300kW.

Pool Heaters Troubleshooting

Heater Won't Turn On or Does Not Stay On 
Clean the filter and turn the thermostat up to try the heater again. A dirty filter can result in low pressure, and if the pressure leaving the filter is low, this will cause the pressure switch to turn the heater off. Check the shut-off valve on gas heaters to ensure that the valve is open and thus supplying fuel to the heater. If the unit is electric, make sure electrical connections are tight and that there is no corrosion at the terminals. If this doesn’t resolve the problem, check the transformer by attaching one voltmeter lead to a terminal on the transformer. Touch the other terminal with the other lead. A reading of between 20 and 28 volts means the transformer is fine. If it is lower than that, there may be a problem with the voltage supply or the transformer. Leave the lead from the voltmeter in contact with the ground or common terminal on the transformer, and check the circuitry connected to the heater as well. Begin by checking the safety fuse, then the high limit switch, and then the pressure switch. If the meter shows voltage, these parts are fine. If it does not, replace them. 

Low Flow or Inadequate Heating 
If your heater shuts off before warming the water to the desired temperature, it may be the result of a dirty filter or an improperly set timer. A dirty filter can prevent the heater from firing. Clean the filter and set the temperature switch to the ON position at a high enough setting that the heater turns on. Reset the timer to allow the heater to run for a longer period. Check the system's valves as well to make sure that they are turned to go through the heater. If this does not resolve the problem, make sure you are using the right size of heater for your pool. If it is too small, it will not heat properly. The pool manufacturer’s product literature will recommend the right-size heater for your pool. 

Noise 
Sometimes your heater may make unusual noises such as bangs, whines, or grinding. The first place to look is your system's hoses and filters. Debris can cause the heater to make knocking or whining noises during operation. Inspect the system for blockages and then back-flush the filter. A noisy heater can also indicate that it is operating after the pump shuts off, and this is related to a faulty pressure switch that needs to be replaced. Turn off the heater and contact a technician if you cannot find the source of the noise. 

1 
Reset the electrical circuit to the filter system and heater by tuning the breaker "Off" and "On." The breaker usually is inside a sub-panel in the pool's equipment enclosure or in the main electrical panel for the house. If necessary, turn on the filter system and cycle through each breaker to locate the one for the pool equipment, then turn off the filter system. 

2 
Press the "Mode" button on the digital heater control panel to put the system in "Standby." Press and hold the "Up" and "Down" buttons simultaneously and wait until the indicator light and digital display flash rapidly, indicating the controls are in the adjustment mode. 

3 
Note if the digital display shows an ignition error code, such as "bD" or "HF" that indicate a problem with the gas-valve relay in the heater. Contact a technician if the controls do not automatically reset the relay in 2 minutes, as indicated when the indicator light and display begin flashing again. Alternatively, if the display doesn't show an error, proceed with resetting the lockout. 

4 
Press the "Up" or "Down" button to set the desired maximum temperature lock setting by noting the temperature shown on the display. Press the "Mode" button and the indicator light and display will flash rapidly. Press the "Mode" button again to lock in the temperature setting. 

5 
Turn on the filter system. If the indicator light flashes slowly, the problem with the ignition lockout is corrected. Contact a technician if the light flashes rapidly or not at all.