1. Is the system switch on?
2. Is the thermostat up to temperature?
3. Is the pump running with a clean filter less than or equal to 16 psi on pressure gauge?
4. Is the gas valve in the on position?
5. Is the pilot lit?
6. Is the gas supply valve open?
7. Are all plumbing and filter valves open?
8. If a bypass is installed, is it properly adjusted?
9. Contact a qualified technician if you still cannot find the problem.

This could be due to low gas pressure, inadequate air supply, or improper venting. Make sure gas is turned on; with propane, make sure the tank has fuel. Also check for water run-off from roof or sprinklers. Check to make sure the heater pilot tubing is intact and not clogged.

The thermostat may be set too low. If the heat loss is greater than the heater input - the heater may be too small, outside air temperature is too low, inadequate gas supply. You may want to install a solar cover to slow heat loss. All heaters have high limit switches to prevent overheating. A faulty high limit could shut off the heater, or the problem could be that the heater is truly overheating, perhaps from improper exhaust.

Inadequate water flow due to a dirty filter, closed valve, external bypass needs adjusting, reversed water connections, or pressure switch out of adjustment. It is also possible that your thermostat is out of calibration or needs replacing.

See previous two questions for additional information. Also check for water run off from above or sprinklers directed at heater. A high wind stack may be needed due to heater location.  Millivolt models have a thermocouple or pilot generator that may be faulty or weak. Loose or rusty connections of the thermocouple to the gas valve or loose coil connection, or short in these wires can shut off a pilot.

Review to the pool heater owner's manual. if you do not find your answer, turn the heater off and contact a qualified service company. Make sure that the gas valves are all in the on position, and if LP, check the gauge on the tank.

The pool heater heat exchanger may be leaking because of chemical or sanitizer damage. The damage may be from winter freeze - usually leaking upon spring start-up. There could be a gasket leaking, or a loose connection to the pressure switch.

This may be caused by condensation (occurring when heating very cold water); a missing or damaged bypass; or excessive water flow through the heater from an oversized pump. Check the heat exchanger for sooting, and make sure the internal bypass is working. Install an external pool heater bypass if necessary.

Either low gas pressure and/or inadequate air supply and venting, review the installation requirements in the pool heater Owner's Manual.  Both conditions may need to be evaluated by a qualified service technician. This is called sooting and could lead to other problems.

One, or a combination of the following: low gas pressure, downdrafting, air supply, and venting. The heater may need a high wind stack, if installed near a vertical wall or windy area. Make sure that the heater is installed with proper clearances all around the outside. Pool Heaters can catch adjacent structures on fire.

Sanitizers or chemical imbalance can deteriorate protective coatings on heater components and create rust. Rebalance chemicals and replace damaged components. Make sure any chemical feeders are installed after the heater, and place a check valve between the two to prevent backflow.

Low gas pressure can cause whistling in the burners. Check your Owner's Guide or contact your installer.

No. Hayward heaters cool down immediately after shut down.

All heaters should be installed on a non-combustible material, such as concrete or block. It must not have any structures above it, if installed outdoors, including tree branches within 4 feet. Consult owner's manuals for clearances around all four sides of your pool heater.

Yes, specific conditions apply. Please consult your owner's manual for complete details. They must be vented to the outside in a very specific manner, and have enough influent air to combust properly. Improperly installed pool heaters have the potential to cause fatalities from carbon monoxide emissions, or gas explosions.

Propane heaters use one gallon of fuel per hour for each 91,000 BTU's of heater input.

Example: A 250,000 BTU heater uses: 250,000/91,000 = 2.75 gallon per hour

Natural gas heaters use one therm (100,000) BTU per 100,000 BTU's heater size. Your gas is usually billed by therms.

• Purchase an energy efficient model.
• Use a pool blanket on your swimming pool when not in use.
• Keep the temperature at the lowest comfortable position.
• Remember to not turn up the heater to maximum, (it will not heat any faster) But set it at a known setting for your desired maximum temp.
• Turn heater off or to a low setting during periods of non use.
• Wind is one of the largest heat thieves. Fences or shrubbery can reduce the effect that wind will have on pool heat loss.

Other Tips to Economize on Pool Heating - from Teledyne Laars:

1 Keep a thermometer in your pool. It will pinpoint accurately the temperature most comfortable for you.

2 Keep your thermostat at the lowest comfortable setting. Each degree more heat than needed could add more to your monthly fuel cost and use up more energy than necessary.

3 Mark the "comfort setting" on the thermostat dial. This will prevent accidental or careless over-heating and waste of energy.

4 Lower thermostat to 70 degrees when pool is to be unused for three or four days. For longer periods, shut the heater off. You will save money on fuel consumption and help conserve energy.

5 Protect your pool from wind. Wind above 3 to 5 miles per hour can lower the pool temperature substantially. A hedge, cabana or decorative fence can be an effective windbreak.

6 Use a pool cover when pool is not in use. This can reduce heat loss by as much as 50%. If you are vacationing for a couple of weeks or shutting down for winter, turn the heater off completely, including any pilot light.

7 Drain heater completely prior to freezing weather. Freezing water inside the heat exchanger can result in costly repairs.

8 Get a maintenance checkup annually. It’s your best ounce of prevention. Call your Teledyne Laars dealer for a skilled technician to do the job. The cost is minimal and the service will keep your heater working efficiently for many years.