Spa and Pool Heating Problems
The heater burner above tray is obviously corroded beyond repair!
1)THE MOST common - the filter is dirty. Heaters have a pressure switch inside which assures an adequate flow of water is going through heater. If the filter is dirty, this will prevent adequate flow thus preventing heater from firing. Also, along the same lines, a pump or skimmer basket full of debris or a clogged pump impeller or clogged plumbing line will also prevent adequate flow. 2)Related to the problem above - the water level is too low, so the skimmer sucks air. Sometimes the water level is just high enough to start flow going and turn on heater, but as pump catches prime, a vortex or swirl of water creates a funnel of air into skimmer which impedes flow and shuts off heater. As pump tries to prime again, the heater will fire then shut off again, cycling on and off-also,if your skimmer has a weir flap it may get stuck in the up or closed postion and cut off water flow. 3)Corrosion - if you have a lazy or ignorant pool service tech he or she may backwash your D.E. filter into the equipment area until the D.E.(the white powder inside filter) builds up until its touching the bottom of the heater box and possibly even going inside. This acts as a wick to keep moisture on the metal box of heater and will not only corrode the heater box, but the whole burner tray as well.Newer heaters such as the Sta-Rite Max-E-Therm heater have a composite shell which will not rust. A less expensive solution is to have the backwash valve plumbed away from the equipment area. Or, if your service tech has liability insurance or at least a bond, have HIM pay for your new heater - if he has no insurance I guess a good beating might give you some satisfaction! 4)Spiders - spiders crawl into the burner orifices and make webs inside that block the flow of gas....this causes four main problems: A) If you have a pilot, and the blocked orifice happens to be on the burner where pilot is attached, the pilot may not catch until the gas from another burner reaches it - causing a little explosion which blows out pilot and shuts off heater. B) If all orifices are blocked, heater may not fire at all. C) If the orifices are partially blocked, heater may fire but the slow flow will not burn completely - leading to longer heating times and/or a strong gas smell. D) Perhaps the spiderweb is in the pilot assembly itself and pilot will not light. On many heaters, its not too hard to clean orifices with a piece of 12 gauge copper wire bent into a loop or hook without even dismantling heater. 5)Sometimes,in a pool/spa combination,if you are trying to heat the spa the valves may be in the wrong position or they have leaking gaskets allowing cold water from pool to enter spa which will increase the time it takes to heat.
Awww....isn't he cute?
6)Rats! They cause heater problems in two main ways: A)Rats love to chew on heater wiring! I don't believe they eat it, but they seem to like chewing the insulation off the wires, sometimes chewing straight through. Spraying DEET (commonly known as "OFF" bug spray) on the wires will prevent this - rats hate the taste! B)Rats also like to make a nest on the top of the burners or on top of the heat exchanger.This causes flames to roll out the bottom and cut off the fusible link assembly (a safety device to prevent fires). Or heat may not be able to escape out the vent and the heaters' high limit may trip.(another safety device)On newer designed heaters it is harder for rats to get inside heater.
The photo below shows the amount of force that can be built up with a combination of pump pressure and heat. On this particular job, the pool equipment was below the pool level, so I closed the valves on the inlet and outlet plumbing to pool equipment to work on pump. When I went to test the pump and heater, I opened the inlet valve just as the customer came out to talk to me. After being distracted, I forgot to open return valve. When I turned pump and heater on, the heater began to smoke, so I immediately shut it off - however, I noticed the pressure valve on filter was continuing to rise, so I shut off pump too. I then realized I had forgotten to open return valve, and as I walked over to open it, the pipe blew up in my face! Luckily, I blocked my eyes with my arm but my arm, belly, and some of my face got steam burns. Its incredible how much pressure can build up in such a short time! The heater only ran about 2-3 seconds before I shut it off,and the pump 4-5 seconds. The old heaters used to come with a pressure relief valve - its probably a good idea to install one on your heater!
(I added the eyebrows to pipe-it looked like a face)
The part above is an ignitor assembly. Newer style heaters use this instead of pilot to ignite main burners. The two wires go to the ignition control module. When the ignition control modules gets "ok" readings from its various safety devices, the control sends power to the ignitor and then opens up gas valve. In this case, the ignitor was not heating up and glowing red like it should, so the control sensed no flame and shut the gas valve off. The new ignitor is obviously on the bottom. It is made from a ceramic/metal composite that is VERY reliable (no pilot orifices to ever get clogged) but also VERY fragile (a slight bump can shatter it like glass) Return from pool heating problems to previous page
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